Chapter 10

Wastewater management

Within the scope of this book, wastewater is considered to mean sullage, i.e. waste water that does not contain excreta or toilet wastes, except those arising from soiled bodies and clothing (Cairncross and Feachem, 1983). Therefore for the purposes of this Chapter, the term wastewater does not include sewage or rainwater.

10.1 Associated risks

Although wastewater may not pose such obvious health risks as excreta or medical waste, there are several indirect risks which should be considered. It is necessary to provide appropriate wastewater management systems in order to:

•

minimise breeding grounds for water-related insect vectors (e.g. mosquitoes);

•

prevent erosion of shelters and facilities;

•

prevent wastewater entering pit latrines or solid waste pits;

•

prevent pollution of surface or ground water sources; and

•

allow safe access to shelters and facilities.

Inappropriate systems, as well as lack of intervention, can increase some of these risks rather than reduce them. Systems involving standing water may inadvertently increase mosquito populations and infiltration systems may lead to the pollution of groundwater sources.

Although the quality of the wastewater may not pose a direct risk to humans (assuming it is not ingested), where wastewater intercepts excreta or refuse disposal sites the risk of disease transmission can increase greatly. Wastewater which spreads toilet wastes or refuse will also spread the likelihood of direct human contact with disease-causing pathogens. This is especially the case where children play or people bathe in the watercourse into which the wastewater is disposed of.

Wastewater can also pose considerable environmental risks, especially where it carries significant components of oil or detergent-based products, and where final disposal sites become stagnant. For this reason it is sometimes necessary to treat wastewater prior to disposal in the environment (see 10.4).

10.2 Sources and types of wastewater

The most common sources of wastewater are:

•

water taps;

•

kitchens/feeding centres;

•

laundries;

•

bathing areas; and

•

clinics.

In most refugee camps, water is carried to dwellings. Where this is the case, volumes of domestic wastewater are generally low and well dispersed, and hence do not pose any serious health hazard. It is still important, however, that people are aware of where and where not to dispose of their domestic wastewater.

Where waterpoints are used for water collection only, the volumes of wastewater produced are likely to be low, resulting from the rinsing of collection vessels and spillage only. The rate of wastewater generation will increase greatly where waterpoints are also used for laundry purposes. For this reason, it is recommended that specified laundry areas are provided with disposal systems able to cope with the quantity of wastewater produced.

In general, wastewater has high turbidity and high values of total suspended solids (TSS); it may also contain oils, detergents and food substances. Total and faecal coliforms may sometimes be present, especially where water has been used for laundry purposes.

10.3 Selection criteria

In determining appropriate interventions for wastewater management there are several important factors to consider:

•

Ground conditions

•

Groundwater level

•

Topography

•

Location and type of water sources

•

Quantity and quality of wastewater generated

•

Climatic conditions

•

Socio-cultural considerations

10.3.1 Ground conditions

One of the key factors in determining an appropriate technology choice for wastewater disposal is the condition of the ground or soil. Infiltration techniques are often adopted but may not always be appropriate. In some instances, ineffective soakpits may pose higher health risks (e.g. as potential mosquito breeding sites) than no intervention at all.

A soakpit or infiltration trench will only be effective if wastewater is able to percolate into the soil. Section 4.3.2 gives guideline infiltration rates for different types of soil and how to identify these soils. Where there is any doubt concerning whether infiltration will work, it is good practice to determine the approximate permeability of the ground by conducting a simple infiltration test.

10.3.2 Groundwater level

The groundwater level will also influence whether infiltration can be used, and seasonal variations in this must be considered. Where the water table is close to the ground surface, infiltration is likely to be severely limited. Soak pits or infiltration trenches that intercept the water table will fill rapidly and are unlikely to cope with large volumes of wastewater. In addition, the risk of groundwater pollution will increase with the height of the groundwater level.

10.3.3 Location and type of water sources

In all cases, it should be a priority to prevent contamination of clean drinking-water sources with wastewater. It is therefore important that the locations of all existing, or potential, water supply sources are taken into account when selecting and designing wastewater management systems. Conversely, drainage possibilities should be considered when selecting and design.ing water distribution points.

Where wastewater is discharged into surface waters, it is important that this is downstream of any water supply intakes. This will prevent increased water treatment requirements. It is also important to consider downstream water use and what the effects of effluent discharge will have on this.

Where groundwater is used as a water source, several factors should be considered if wastewater is disposed of by infiltration. Although the ground will act as a filter and remove impurities as the wastewater travels to the aquifer, the following safety measures should be taken:

•

Soakpits or infiltration trenches should be at least 30m horizontal distance from any groundwater source (e.g. well, borehole).

•

Disposal sites should be downhill of groundwater sources where possible.

•

The base of any soakpit should be at least 1.5m above the water table.

•

Where wastewater contains a high oil component, water should be treated prior to disposal.

10.3.4 Topography

The topography of the affected site will be a key factor in determining whether surface drainage techniques can be adopted. It is rare to find a site that is completely flat, although where this is the case, or nearly so, surface drainage becomes almost impossible. In general, a minimum gradient of 1 in 200 is recommended for the transport of wastewater in earth drainage ditches (Davis and Lambert, 1995). Where drainage channels have to circumnavi.gate natural obstacles, such as mounds or hillocks, this may increase labour time and costs considerably.

10.3.5 Quantity and quality of wastewater generated

The volume of wastewater generated will also influence the technology choice made. Where there are only small quantities of wastewater, infiltration may be appropriate even in low-permeability soils, or these may be removed rapidly through evaporation. Where larger volumes are involved, disposal systems must be selected and sized accordingly. Existing systems may become inappropriate if water use increases greatly, and will need upgrading or replacing. Guideline wastewater generation rates for public institutions are as follows:

•

Field hospital: 55 litres/person/day

•

Cholera treatment centre: 100 litres/person/day

•

Feeding centre: 25 litres/person/day

•

Out-patients clinic: 100 litres/day (total)

Whilst the quality of wastewater is not of major importance in most cases, with low numbers of pathogens, this should also be considered. Wastewater from water collection points is unlikely to require treatment, whilst that from kitchens or hospitals probably will.

10.3.6 Climatic conditions

Climatic conditions will also affect intervention selection. In hot, dry climates evaporation or irrigation use of wastewater may be viable. In wetter climates the volume of rainfall must be considered, and may even be used in removing wastewater.

In colder climates the possibility of drainage pipes or systems freezing should not be overlooked.

10.3.7 Socio-cultural considerations

Although wastewater management in general is a less sensitive issue than excreta disposal or hygiene promotion, socio-cultural aspects should also be considered. Where surface drain.age channels pass through residential areas this may create temptation for people to use wastewater for domestic purposes, and it may be difficult to deter them from doing so.

Cultural practice and tradition, in terms of water use, may also influence the volume of water used and wastewater generated. This may also affect when wastewater is produced, for example if large numbers of people bathe or do laundry at a particular time of day.

10.4 Technology choice

The immediate action options for wastewater management are generally the same as those for longer term intervention. It may be appropriate, however, to implement a simple option in the emergency phase and develop this further at a later date. Whenever possible, wastewater should be disposed of close to the point of origin. The simplest method, where possible, is to divert wastewater to local watercourses. The most common method in emergency situations is probably infiltration. The technology choices included here are:

•

Soakaways or soakpits

•

Diversion to natural drainage

•

Diversion to man-made drainage

•

Infiltration trenches

•

Bucket basins

•

Evaporation pans

•

Evapotranspiration beds

•

Irrigation use

10.4.1 Soakpits

A soakpit, or soakaway, is simply an excavation in the ground which facilitates the percola.tion of wastewater into the surrounding soil. As well as wastewater from the sources outlined above, a soakpit can also be used to dispose of the effluent from a septic tank or aquaprivy. By spreading the effluent over a sufficiently large soil area the water is treated and absorbed efficiently. Depending on the wastewater quality, a film of organic slime may develop on the walls of the soakpit and just inside the soil (Figure 10.1). As the wastewater passes through the slime it traps suspended particles and the organisms which live in the slime feed off the waste products in the effluent. If the flow is too high, the slime layer will grow until it completely blocks the soil, preventing any further flow of wastewater.

The treatment process is much more efficient if the soil is kept well oxygenated. This requires the soil to be alternately saturated with effluent and dried to allow the entry of air. In well-designed systems this happens naturally because of the daily variations in flow. The process is far less efficient in constantly saturated conditions such as below the water table.

Whether a soakpit will function or not depends primarily on the permeability of the soil. Soil pores may become clogged with time and this can reduce the infiltration capacity of a particular soakpit. Seasonal variations in the water table can also affect the performance greatly, and a soakpit which works perfectly in the dry season may overflow at other times of year.

Soakpits are commonly between 2 and 5m deep and 1 to 2.5m in diameter. Wastewater entering the pit may soak into the surrounding soil through the sides and base of the pit. If the water has a high solids content, however, the base of the pit will quickly become blocked with silt and sludge. Where this occurs infiltration will only take place through the pit walls, therefore the base area is ignored when designing soakpits.

Most pits in emergency situations are not lined but filled with large stones, blocks, bricks, etc. (Figure 10.2). This fill is to support the pit walls and the cover. It does not play any part in the treatment of wastewater and its volume should be deducted when calculating pit volumes.

Advantages: Soakpits are easy and relatively quick to construct; and can be used on flat sites.

Constraints: They are only appropriate in permeable ground conditions; and can only cope with a limited volume of wastewater.

Alternatively, the pit can be lined (Figure 10.3). Any lining must be porous so that the wastewater can reach the soil surface. The top 0.5m of any pit must have a sealed lining in order to prevent the infiltration of rainwater.

The size of a soakpit depends on the volume of liquid to be disposed of and the type of soil in which the pit is excavated. It may be calculated by using the following process:

1.

Calculate the surface area of pit wall required for infiltrating the wastewater: Pit wall area (m2) = daily wastewater flow (litres) ÷ soil infiltration rate (Table 4.3)

2.

Choose a pit diameter.

3.

Calculate the depth of pit required to dispose of all the liquids: Depth of pit required = pit wall area ÷ (π x pit diameter)

4.

Add 0.5m (lined depth) to calculate the total pit depth needed.

Worked example: A soakpit is required to dispose of 500 litres per day in a sandy loam soil (infiltration rate = 25 litres/m2/day: see Table 4.3). There is space for a pit of 2m diameter only.

Pit wall area = wastewater flow ÷ infiltration rate = 500 ÷ 25 = 20m2 Depth of pit = pit wall area ÷ (p x pit diameter) = 20 ÷ 2π = 3.2m Total depth of pit = depth of pit + 0.5m = 3.2 + 0.5 = 3.7m Note: Wastewater from large institutions, such as hospitals, is likely to be far too great in

volume to be disposed of in a single soakpit.

Poorly designed soakpit, Tanzania

10.4.2 Infiltration trenches

An infiltration trench is a variation on a soakpit. Its advantages are that it provides a higher surface area for the volume of soil excavated, and it uses the upper soil layers which tend to be more porous. Instead of directly entering a pit, the wastewater is dispersed by pipes along a series of trenches that have been filled with coarse gravel (Figure 10.4).

The pipes are porous so that the wastewater can seep out into the surrounding gravel, and from there, through the walls of the trench into the soil. Pipes can be made from porous materials such as concrete made without sand, or small holes or slots can be cut in the walls. Pipes are laid horizontally to allow the water to be distributed evenly along the whole length. The size of the pipe depends on the volume of flow but for most situations 100mm diameter is sufficient.

The top of the pipe is covered with a layer of paper, straw or porous plastic sheeting. This allows air to enter the trench and gases to escape but prevents the topsoil from mixing with the gravel and blocking the trench.

Trenches should be as narrow as possible since it is only the side walls that absorb the effluent. Generally the trench should be 300-600mm wide, and a depth of about 1m below the bottom of the distribution pipe.

Advantages: Trenches are easy and relatively quick to construct; can be used on flat sites; and can cope with a greater amount of wastewater than a soakpit of the same volume.

Constraints: They are only appropriate in permeable ground conditions.

The length of an infiltration trench can be calculated by using the following process:

1.

Calculate the surface area of trench wall required for infiltrating the wastewater: Infiltration area (m2) = daily wastewater flow (litres) ÷ soil infiltration rate

2.

Calculate the total length of side wall required: Total length of side wall = infiltration area ÷ trench depth below distribution pipe

3.

The length of trench required is half of the total length of side wall.

Note: Ideally, the infiltration rate should be measured at a number of places in the drainage area, since soil texture changes very quickly. Details of how to do this can be found in Chapter 4.

10.4.3 Natural drainage

If natural drainage can be used to dispose of wastewater to flowing streams or rivers then this should be used. Care must be taken to ensure that this occurs downstream of water sources, and in general a slope of at least 1 in 200 is required for water to drain effectively in earth channels. Lined drainage channels (e.g. concrete) are likely to be effective on lesser slopes, but are costly and time consuming to construct, and unsuitable in most emergency situations.

Wastewater with high organic content, including laundry wastewater, should not be diverted to stagnant ponds, where it may become anaerobic and offensive. Discharging large volumes of wastewater to small watercourses may also cause periodic overflowing, leading to pooling of stagnant water.

Advantages: A minimal amount of construction work is required; and there are negligible physical effects on landscape.

Constraints: It is rarely possible; and may inadvertently pollute watercourses.

10.4.4 Man-made drainage

In some sites it may be appropriate to construct drainage channels cutting through natural obstacles, such as earth mounds or hillocks, to reach an existing water course. This is likely to be arduous work, expensive and time consuming. However, it may be the only option where infiltration is impossible and where natural drainage leads to stagnant or hazardous conditions.

Advantages: It may be the only option in impermeable sites with small gradients.

Constraints: It is expensive and time consuming to construct; and may have a large impact on the surrounding landscape.

Manual

10.4.5 Evaporation pans

An evaporation pan is a shallow pond which holds water and allows it to evaporate (Figure 10.5). Evaporation rates depend upon solar radiation, temperature, humidity and windspeed. Wastewater can be disposed of to evaporation pans in hot, dry conditions where evaporation rates considerably exceed rainfall rates for the operating period.

In general, large areas of land are required for evaporation pans to work successfully. Even a high evaporation rate of 5mm/day requires a surface of area of 200m2 per cubic metre of liquid per day (Davis and Lambert, 1996). Assuming that there is no infiltration of water into the soil, the area required can be estimated by using the following equation:

Area (m2) = Volume of wastewater per day (m3) x 1000 Evaporation rate (mm/day)

Evaporation rates are difficult to determine and meteorological instruments are required. Measuring direct evaporation of water from an evaporimeter is the simplest method although this still requires the collection of additional rainfall data. Alternatively, evaporation can be estimated mathematically from measured climatic factors (i.e. air temperature, humidity, sunshine and windspeed). Information regarding how to conduct such measurements is contained in most field hydrology textbooks but the best solution is to obtain data from nearby weather stations (where possible). In general, evaporation pans should only be used for wastewater disposal where there is a mean evaporation rate of at least 4mm/day, where rainfall is negligible and where there is no viable alternative.

Surface wastewater

Evaporation area

Vegetation

Earth bank

Figure 10.5. Evaporation pan

Manual

Pans should be sited far away from habitation to limit water-related insect hazards (e.g. mosquitoes) and require careful management if they are to be effective. Provision will need to be made for managing possible overflow during periods of rainfall and regular mainte.nance is likely to be necessary.

Advantages: Evaporation pans are suitable in arid conditions where other disposal methods, such as infiltration, are inappropriate.

Constraints: They may encourage mosquitoes, flies, etc; and large areas are required.

10.4.6 Evaporation and evapotranspiration beds

Evaporation beds can be used where infiltration methods cannot, but are only suited to dry, arid climates. This method relies on capillary action to draw water to the surface of shallow sand beds, where it is evaporated to the atmosphere. An improvement on this is the evapotranspiration bed (Figure 10.6) which increases the rate of water removal by planting vegetation in the bed to draw up water and encourage transpiration.

Solid materials should be removed from wastewater before it is allowed to enter the sand bed through a system of distribution pipes. The perforated pipes should be about 1m apart and surrounded by uniform-sized gravel or stone (typically 20-50mm diameter). A permeable filter cloth is placed over the gravel, and the bed is filled with sand and covered with a layer of topsoil in which grass is planted. To keep beds aerobic and prevent clogging they should be as shallow as possible, and not more than 1m deep.

The size of an evapotranspiration bed will depend on local evapotranspiration and rainfall rates (available from nearby weather stations), and daily wastewater flow (or loading rate). Loading rates of up to 10 litres/m2/day can be applied, although performance will depend on soil type, vegetation, wind speed, humidity, solar radiation and temperature. Any rainfall runoff should be diverted around the system.

Vegetation

Slope

Topsoil

Ground level

Sand

Perforated pipe (PVC)

Filter cloth Stone

Figure 10.6. Evapotranspiration bed

Advantages: These beds are suitable in arid conditions where other disposal methods are inappropriate.

Constraints: Careful management is required; and the beds can only cope with a limited volume of wastewater.

10.4.7 Irrigation

Where large volumes of wastewater are generated it may be appropriate to make use of this for small-scale irrigation. This may simply consist of planting fast-growing fruit trees, such as papaya or banana, in the drainage channels. Alternatively, drainage channels may be used to divert the flow to small areas of arable land which may be deliberately flooded with wastewater to promote plant growth.

In general, wastewater cannot be used for large-scale irrigation and careful monitoring should occur to ensure that clean drinking water is not diverted for irrigation use, especially where there is a limited water supply.

Advantages: Irrigation can make use of large volumes of water; and contributes to agricul.tural activity in the affected area.

Constraints: In general, small-scale possibilities only are viable; and it may encourage inappropriate use of drinking water.

10.5 Wastewater treatment

Although many of the methods outlined above involve some treatment as well as simple disposal of wastewater, it is sometimes necessary to implement additional treatment facili.ties. Where wastewater has high solids, oil or detergent content it will be necessary to separate these components prior to disposal. This is likely to be especially appropriate for wastewater from kitchens or feeding centres catering for large populations.

10.5.1 Solids removal

Wastewater with a high solids content should be strained, especially if infiltration techniques are to be used. This will prevent soil pores from quickly becoming clogged and preventing infiltration. A simple method of solids removal is to pass the wastewater through a woven sacking strainer. Alternatively a crude plastic filter may be made by cutting small slots in the base of a plastic bucket. These should regularly be inspected and cleaned as required.

10.5.2 Grease traps

A grease trap, as the name suggests, is designed to trap grease or oil and allow treated wastewater out. This should be sited upstream of the final disposal system. A simple grease trap (Figure 10.7) consists of an inlet with a strainer to remove solids, and a series of baffles. These baffles are designed to trap grease, which floats to the liquid’s surface, so that only clean water travels underneath and eventually out through the overflow. Grease traps should be emptied of grease at regular intervals, preferably daily. Traps can be built from bricks, blocks, wood or an oil drum cut in half along its longest axis.

10.5.3 Settlement tanks

A more sophisticated version of the grease trap is a settlement tank (Figure 10.8). This works on the same principle to trap grease or ‘scum’ on the liquid surface and also allows suspended solids to settle forming a sludge deposit on the base of the tank.

The outflow from the tank should go to a soakage pit or trench, or a nearby watercourse. The settled material in the tank should be removed and buried when the tank is about one-third full of solids. Table 10.1 indicates appropriate settlement tank sizes for different flow rates (see 10.3.5 for guideline flow rates).

Inflow rate (litres/day) Liquid deptha (m) Tank lengthb (m) Tank width (m)

2000 5000 10000 15000 20000 1.2 1.4 1.5 1.5 1.5 1.9 2.8 3.3 3.4 4.0 1.0 1.4 1.7 1.7 2.0

a Allow 30cm extra tank depth above liquid level b First compartment twice the length of second

These sizes assume that the solids will be removed from the tank every three months. Where the system is to become permanent, a larger tank may be constructed which needs emptying less often.

Settlement tanks may be constructed above or below the ground. The tank walls can be built from concrete, bricks, timber or earth. The tank should have a minimum depth of 1.2m to allow adequate settling, and at least 0.3m between the liquid surface and the base of the cover for ventilation. The inlet and outlet may be made using a ‘tee’ piece (Figure 10.9), or for larger units a weir may be used for the outlet.

10.5.4 Septic tanks

In a large public institution such as a hospital or medical centre septic tanks can also be used for disposal of wastewater from kitchen, laundry and washing facilities. This dilutes the effluent from toilets and can be used for treating both sewage and grey wastewater (see Section 6.8.10 for design details).

10.5.5 Reed beds

Man-made reed beds (or constructed wetlands) treat wastewater by removing organic matter, oxidising ammonia, reducing nitrate and removing phosphorous (Cooper et al., 1996). Reed

Manual

beds can be used to treat sewage effluent as well as sullage and generally consist of a gravel-filled bed covered with a layer of soil or sand in which reeds are planted. Once treated the 1 water can be discharged to a natural watercourse. There are two main types of bed, either

2

vertical flow or horizontal flow.

3

Figure 10.10 shows a horizontal reed bed where wastewater is fed into the bed via an inlet stone distributor (resembling a small soak pit). Wastewater flows horizontally from the 4 distributor at one end of the bed to an outlet at the other. A30-50cm depth of water should be

5

maintained in the bed. Horizontal flow beds are simple to operate and maintain but take up more land area than vertical flow beds.

6

7

8

Inlet Reeds 9 Level surface

10

11

12

13

Inlet stone Gravel Sloped base ~1:100 Outlet distributor

Figure 10.10. Horizontal reed bed

Manual

Vertical flow reed beds allow wastewater to trickle down through the bed media as illustrated in Figure 10.11. Here the wastewater must be introduced to the system in batches so that the bed is completely flooded for a while and is then allowed to drain. This allows air to be trapped in the soil and the extra oxygen results in more effective removal of nitrogen compounds and phosphates from the wastewater (Smith, 2001). Vertical flow beds require more intensive management than horizontal beds and a secondary system for holding back each batch of wastewater is required.

Reed bed systems must be carefully sized (see Cooper et al., 1996) and inlet troughs and pipes should be cleaned at monthly intervals to prevent blockages.

Inlet: Intermittent dosing of waste water

Perforated pipe Reeds

Sharp sand

Layers of gravel of increasing size

Outlet

Perforated pipe Sloped base

Figure 10.11. Vertical reed bed

10.6 Cholera treatment centres

Wastewater from medical installations dealing with specific epidemics, such as cholera treatment centres, should have independent wastewater management systems. It is important that any infection is contained and that the spread of epidemic is minimised. Large waste volumes of chlorine-based disinfectants are also likely to be produced in such cases, since these are used to wash down facilities and equipment. In general, such installations should have their own septic tank and underground disposal (e.g. soakpit) isolated from both ground and surface water sources.

10.7 Rainfall runoff

Although this book is not dealing with site drainage specifically, it is important that this is considered, especially in areas of high rainfall. Drainage of rainfall runoff may be essential to prevent erosion of soil and soil-based buildings, to allow safe access and movement around the site, and to minimise areas of standing water. It is also important that sanitation facilities such as pit latrines, refuse pits and soakpits are designed so as not to fill with rainwater following heavy rainfall, in order to prevent the spread of disease.

In general, drainage channels should be constructed to ensure that the site does not become a swamp every time it rains. These channels may also be used to dispose of wastewater which may be diluted with rainwater. All drainage facilities must be adequately maintained, and regular inspection and cleaning should be conducted.

References and further reading

Adams, John (1999) Managing Water Supply and Sanitation in Emergencies. Oxfam: Oxford. Ayoade, J.O. (1988) Tropical Hydrology and Water Resources. Macmillan Publishers: Basingstoke & London. Cairncross, S. and Feachem, R. (1983) Environmental Health Engineering in the Tropics: An introductory text. John Wiley & Sons: Chichester. Cooper, P.F., Job, G.D., Green, M.B. and Shutes, R.B.E. (1996) Reed Beds and Constructed Wetlands for Wastewater Treatment. WRc: Swindon. Davis, Jan and Lambert, Robert (1996) Engineering in Emergencies: A practical guide for relief workers. RedR / IT Publications: London. Médecins Sans Frontières (1994) Public Health Engineering in Emergency Situation. Médecins Sans Frontières: Paris. Reed, R. and Dean, P.T. (1994) Recommended Methods for the Disposal of Sanitary Wastes from Temporary Field Medical Facilities. Disasters Vol 18, No 4. Smith, Mike (2001) Wastewater Treatment: A postgraduate distance learning module. WEDC, Loughborough University: UK.

Significant Water Management Issues in Ireland

Public Consultation Submissions Part 5

Contents

Nigel de Haas 1

Vincent Dwyer Leitrim County Council 4

Jerry Long ICOS 17

Micheal Lehane EPA 24

Ita Harty Dungarvan Shellfish Ltd 33

Cornelia Wahli 37

Bernadette Connolly Cork Environmental Forum 39

Breian Carroll ACA 48

Alec Rolston An Foram Uisce 61

Ciaran O Kelly Kells Tackle anglers 130

From: Nigel de Haas

Sent: Tuesday 4 August 2020 13:30

To: rbmp

Subject: Private Nigel de Haas

Aachments: Submission on draL SWMI Report.pdf

SWMI Consultan

Water Advisory Unit

Department of Housing Planning and Local Government Custom House Dublin 1 D01 W6X0

A Chara,

Aached please find my submission on the dra SWMI report and the vital issues that need to be addressed in the period 2022 – 2027.

Mise le meas,

Nigel de Haas

Public Consultation

Draft Significant Water Management Issues (SWMI) Report

Submission by Nigel de Haas

4th August 2020

A Chara,

I am pleased to make the following observations on the draft SWMI report:

1. An evaluation of the efficacy at catchment and waterbody scale of national initiatives presented as solutions in the 2nd River Basin Management Plan must be presented to the public in order to provide the information and evidence base for decision making around their continuation and an assessment of the need for additional supplementary measures.

The approach to implementing the Water Framework Directive whereby certain areas, Priority Areas for Action are selected for targeted measures and others are left to basic regulations is completely unsatisfactory. I am concerned that the draft now proposes “to continue with this approach for the third cycle River Basin Management Plan.”

This will result in the majority of waterbodies which are currently failing Water Framework Directive’ standards (or ‘at risk’ of doing so) NOT being targeted with specific measures during the 3rd River Basin Management Plan and so continuing to fail. There is a clear political commitment in the Programme for Government to ‘ensure that the State complies with the EU Water Framework Directive’. The approach being proposed in the draft report clearly runs counter to this.

2.

The prioritisation approach does not follow the procedure set out in the directive for exemptions from the achievement of Water Framework Directive objectives and thus is not compliant with the directive. The most recent report from the Environmental Protection Agency states that more than half our rivers, lakes and estuaries (47%; 49.5%; and 62% respectively) are not in a healthy state i.e. they are failing Water Framework Directive mandatory standards of ‘good ecological status’ and river water quality has declined by 5.5%.

All of these are subject to basic national legislation, demonstrating the fact that basic measures are not adequate. In order to secure the necessary resources to implement action for all our waters, the River Basin Management Plan should clearly state what objectively needs to be done. In order to apply exemptions in relation to disproportionate cost the mandatory economic analysis required by the Water Framework Directive must be conducted.

3.

The Water Framework Directive requires inter alia:

•

“Estimation and identification of significant water abstraction for urban, industrial, agricultural and other uses, including seasonal variations and total annual demand …”;

•

The establishment of “controls over the abstraction of fresh surface water and groundwater, and impoundment of fresh surface water, including a register or registers of water abstractions and a requirement of prior authorisation for abstraction…” (Art. 11.3(e))

While Member States ‘can exempt from these controls, abstractions or impoundments which have no significant impact on water status’ it is impossible to assess the significance or otherwise of an abstraction, especially in the context of cumulative impacts in the catchments of groundwater-dependent terrestrial ecosystems unless one knows of their location and volume.

Detailed understanding of abstraction pressures in Ireland or their interaction with spatially heterogeneous impacts of climate change has yet to be developed, especially cumulative impacts of unmonitored abstractions on potentially vulnerable and / or high status waters . In order to secure this, a full picture of abstractions in state, is necessary, hence to requirement for a comprehensive National Abstraction Register.

It not appropriate to remove abstraction as a specific significant water management issues because:

•

Impacts of abstraction tend to be localised and can take time to materialise and may not be detected by high level EPA monitoring and characterisation ;

•

Abstraction has been identified as a Significant Water Management Issues in the previous two cycles of the River Basin Management and I am not aware of any new material that has emerged to support removing it;

•

According to the draft report, abstraction has been identified as one of the ‘top five pressures reported for water dependent habitats’ under the Habitats Directive;

•

With 84% of water-dependent habitats in unfavourable conservation status and many of these related to catchments of high status waterbodies whose protection and restoration is a stated priority, any pressure on these must be treated with the utmost seriousness and identified as a significant issue.

Thanking you for your attention.

Mise le meas,

Nigel de Haas

From: Vincent Dwyer

Sent: Friday 7 August 2020 10:02

To: rbmp

Cc:

Subject: Leitrim County Council

Aachments: 2020 Significant Water Management Issues in Ireland (SWMI) -LCC Environment

Department .docx

Hi,

I enclose submission for consideran Regards

Vincent Dwyer Head of Finance, Water, Environment, Climate Acgency Services Leitrim County Council, Aras An Chontae, Carrick on Shannon

(Designated Public O.cial under the Regulan of Lobbying Act 2015)

6thAugust2020

SignificantWaterManagementIssuesinIrelandConsultation WaterAdvisoryUnit DepartmentofHousing,Planning, andLocalGovernment Custom House Dublin1. DO1W6XO

DearSir/Madam Leitrim CountyCouncilwelcomesthePublicConsultationopportunityonthe“Significant Water Management Issues in Ireland” DocumentproducedbytheDepartmentofHousing,Planning CommunityandLocalGovernment.

CountyLeitrim“LovelyLeitrim”islargelydependentontourism andthenaturalbeautyofthe CountytopromotetourismandtogeneratemuchneededeconomicspendintheCountyandwider borderregions.SustainabilityforLeitrim isextremelyimportantinprotectingournaturalwater resourcesandtheenvironment.

Leitrim CountyCouncilworkingonbehalfofCo.Leitrim hasanumberofobservationstomakein relationtothe‘SignificantWaterManagementIssuesinIreland’whichshouldbeaddressedinthe planningprocessforthenext2022-2027RiverBasinManagementPlan;theseareasfollows:

1. ThereareanumberofWasteWaterPumpStations(WWPS)intheCountyservicing estateswhichhavenotbeentakenincharge.Inlightofpotentialriskto waterquality, IrishWatershouldbegivenresponsibilityforsuchWWPS,toensuretheyhavepower connectedandarefitforpurposeanddischargingtothepublicsewernetworkwhich formspartoftheIrishWaterinfrastructure.Thiswillimmediatelyimprovewaterquality, preventmajorpollutionincidentsandallowallassociatedhealthandsafetyrisksat thesestationsto bemanagedbyIrishWater. IrishWatershouldbeincontroloftheir “DrainageAreaPlans” andallfoulinfrastructurewithintheseareas,includingthegravity

foulsewerandthefoulrisingmainswithassociatedfoulwaterpumpstations.Irish

Watershouldhaveadutyofcarewithregardtoallfoulnetworkconnectionsfrom privateestatestotheirpublicfoulsewers.IrishWateristheresponsiblebodythatgrants andapprovestheconnectionsto theirfoulsewersandtheyshouldhaveresponsibility andappropriatefundingtodealwithsuch“legacy”issues.

2. IrishWaterisresponsibleforallotherWasteWaterTreatmentPlantsWWTPsinCo. Leitrim.Itmustbenotedthatmorethan50%ofthesearesizedat<500p.eandonly requireanEPACertificateofAuthorisationfortheirfinaldischarge.Themonitoringdata forthesesmallerWWTPsisnotrecordedinthemonthlydatabookthatLocalAuthorities returnto IrishWater.SuchWWTPsareonlymonitored2xperyearandthelimitsare BOD25mg/l,SS35mg/landCOD125mg/.ThenutrientsAmmoniaandPhosphorousin thefinaleffluentsdischargedfromtheseWWTPsto surfacewatersisnotmonitored. TheCertificatesofAuthorisationhavenotbeenreviewedsincetheyweregrantedor thereisno CertificateavailablefortheWWTP.Thissituationismostlikelynotuniqueto Co.Leitrim.TheSurfaceWatersRegulationsrequiresthattheassimilativecapacityofthe receivingwatersiscalculatedforeverydischargeandalloftheseexistingCertificates shouldbereviewedbyIrishWaterasthelicenseeduringthe3rd cycleoftheRBMPsin conjunctionwiththeEPA.

Thereareanumberofthe<500p.e.WWTPsinCo.Leitrimwhicharepartofa“Design, BuildandOperate” (DBO)bundleofschemes.TheDBOContractwastenderedbefore theSurfaceWaterRegulationswerecommencedandthereforetheContractLimitsfor theDBOOperatorhavebeenagreedwithoutconsiderationoftheassimilativecapacity ofthereceivingwaters. Theseschemeshavea30(thirty)yearoperateperiodand contractuallyitwillbecomplicatedto carryoutrefurbishmentworks,butthisisamatter whichIrishWatershouldberequiredto undertakeduringthe3rd RBMPcycle. Thesignificanceoftheimpactofthenutrientsinthepointsourcedischargesfrom these<500p.e.WWTPsshouldbequantified,thenutrientsshouldbemonitoredandany adverseimpactonwaterqualitycanbeaddressed.IrishWatermaynotbefullyawarein allcircumstancesofthepotentialproblemsthese<500p.e.WWTPsarecausing. CurrentlythemonthlydatabookthatLocalAuthoritieshavetoreturntoIrishWateronly requiresreportingforWWTPs>2000p.e.andthereisno requirementto preparean AnnualEnvironmentalReportfortheEPAfor WWTPs<500p.e.withaCertificateof Authorisation. IrishWatershouldhaveaccessto fundingto carryoutthenecessary

capitalreplacementandupgradeworksrequiredoncetheimpactofthenutrientsinthe

dischargeisquantified.

Ofadditionalsignificanceistheagedsewernetworksconnectedto theseCertificate WWTPs,whichallhavecombinedstormoverflows(CSOs)andstorm wateroverflows (SWOs)allofwhichareunquantifiedpotentialpathwaysforthedischargeofnutrientsto waters.

3. Typicallysmaller<500p.e.WWTPsdo nothaveanyinletcontrolsorstormwaterholding tanksandquicklybecomeinundatedwiththeincreasedvolumeofwater/wastewater arrivingduringperiodsofheavyrainfall.Incidentsarisinginthisregardshouldbe reportableto theEPA.InbetweentheseperiodsofheavyrainfalltheWWTPhasto re.establishtheefficiencyofthetreatmentprocess,ittakestimeforthebacteriatore.establishthemselvesbeforethereisoptimumtreatment.IrishWatershouldbeprovided withthenecessaryfundingto improveandupgradethesesmaller<500p.e.WWTPsto providegreaterprocesscontrolandstormwatercontrol.Itwouldbebeneficialforwater qualityimprovementifIrishWatercouldbedirectedduringthe3rdRBMPCycleto continuetodevelopdrainageareaplansforthesmalltownsandvillageswhereleaking sewers,misconnectionsandpoorlyconstructedcombinedsewersexist;especiallyif thesearelocatedwithinPriorityAreasforAction. Thestormwaterfromseweredareas shouldhaveindependentstorm waterdrainagesystemswherepossible.

4. Climatechangeandtheassociatedincreasedrainfallamountsandchangingseasonal weatherpatternsarealsoproducinganotherproblemof‘flooding’inthesewer networks.Thisisaffectingpumpstationswhicharelocatedadjacentto rivers;thewater levelsintheseadjacentriverswillriseespeciallyduringthewintermonths,whenthis levelrisesabovetheemergencyoverflowlevelsofthepumpstations. Thepump stationsstartto becomeinundatedbecausetheriverwaterflowsintheoverflow.The riverwaterflowsintothepumpstationviatheemergencyoverflowcausingthe water/seweragelevelinthepumpstationsto rise.Thepumpshavetopump continuouslyinthissituation,to tryandkeeptheleveldownintheWWPS.Thisleadsto theretentionofsewerageinthesewernetwork,itleadstosettlementandodourissues, thisbackpressureonthenetworkcausesmanholestolift,problemswithinternal plumbinginhousesatlowlevelsandcreatesaseriouspublichealthissue.Italsomeans

thereisa‘diluted’continuousinfluentbeingpumpedforwardfortreatmentwhich

causesanimbalanceattheWWTPandcanleadtobacterialdie-offinthetreatment process;andapartiallytreatedfinaleffluentdischargeto waters.IrishWatermustget thenecessarycapitalinvestmentfundingtoaddressthedeficitinnetworksaswellas wastewatertreatmentplants.

5.

Land-Use planning is a significant water management issue, planning and environment sectionsshouldbeworkingtogetherwith‘joinedup’nationalpolicieswhichincorporates the objectives of the River Basin Management Plans (RBMP). This willhelp to strengthen the ‘Protect’ objective of the RBMPs and align with County Development Plans. Water Qualityshouldnotbeseenasbeinginconflictorversusdevelopmentasthisleadstopoor decisions being made which won’t be based on the integrated ‘planning policy & WFD’ prioritiesinthedecision-makingprocess.

There is a lack of cost-effective solutions for Domestic Waste Water Treatment Systems (DWWTS) on low permeability soils and for existing sites with site restriction issues; protecting water quality should not be incompatible with rural development. Practical guidance which can be used to carry out a WFD check, to assess the impact, the assimilativecapacity,whichprovidesguidanceonthecumulativeimpactsonwaterquality is required. There is a concern with regard to the quality of the technical reports being submittedfor DWWTS. ARegulatoryBody such as the EPA shouldhave aRegister ofSite Assessorswithassociatedregulation.TheSiteAssessorcouldbeincludedontheRegister through the payment of an annual membership fee and the continuance of ongoing training (equivalent to Continuing Professional Development). The EPA’s National Inspection Plan (NIP) inspection which the Environment Department carry out in Co. Leitrim has a high failure rate for these NIP inspections with issues relating to poor installation,incompleteinstallationandalackofmaintenancebeingthemostcommon.

6.

The Department has recently announced changes to the existing grant scheme for DomesticWasteWaterTreatmentSystems(DWWTS)undertheEPA’sNationalInspection Plan;withtheremovalofthe incomethreshold andthe increasein the grantfrom €4000 to €5000 (85%). In addition 2 (two) further new grant schemes are being introduced, namely:

a.

New grant scheme for domestic waste water treatment systems under the EPA’s NationalInspectionPlaninaPrioritisedAreaforAction

b.

New grant scheme for domestic waste water treatment systems under the EPA’s

NationalInspectionPlaninaHighStatusObjectiveCatchmentArea.

These are welcome schemes and mutually beneficial to the householder and to water quality.However,itmaybeamissedopportunityasthequalifyingcriteriaforeachgrant schemerequiresthattheDWWTSwas registeredbefore the1st February2013orafterif the system was installed since then. This criteria should be removed as it will leave a number of affected people with deficient DWWTS ineligible to apply for the grant scheme. It would be better if the criteria required the DWWTS to be registered as a conditionofreceivingthegrantandpriortopaymentofthegrant.

The Department should allow people outside of these areas to apply for a grant to improve/upgrade their DWWTS, instead of the current situation (outside of the Priority Areas for Action and the High Status Objective Catchments) whereby the grant scheme can only be availed of if you fail an Inspection under the National Inspection Plan (NIP) Programme2018–2021andyourDWWTSwasregisteredpriorto1st February2013.This wouldopenuptheapplicationstoamuchwiderrangeofhomeownersandwouldprovide animportantfinancialincentivetocarryoutahigherstandardofremediation.Thiswould be a significant far reaching Measure that would ensure Ireland meets EU targets for implementation,itwouldbeaveryimportantPublicHealthinitiative,forsiteswithpoorly performingDWWTS.Improvingpublichealthforall,particularlyforpeopleusingdomestic wells located on such sites would have an associateddirect improvement on their water quality. InCo.LeitrimtheEPA’sNationalInspectionPlan(NIP)hasidentifiedthattypically theDWWTSthatfailtheNIPinspectionrequireveryexpensiveremediationworks.Dueto the highlevelofinvestment requiredbythe homeowner fortheremediation;progressis typically slow and difficult, particularly if their DWWTS wasn’t registered by 1st February 2013 and they are ineligible for the grant scheme. A lack of regulation, licensing of the area of site suitability is also a significant problem. The Competent Site Assessor and AssignedCertifier shouldhave adequate professionalindemnityinsurance and shouldbe fullyresponsibleforthedesignoftheDWWTS.Theyshouldcertifyitsdesignandsupervise theinstallation/constructionandcommissioningwithasignoffforeachstage.Uponfinal completion a Certificate should be required to certify the final Design/Installation/ConstructionandCommissioningoftheDWWTS;withanOperational bond/guarantee for the DWWTS for aminimum 5–10year operational period. The Site Assessorisafundamentalpartoftheseimprovementworksandtheassociatedimpacton waterquality.

7. Forestry has been identified as the fourth most prevalent significant pressure impacting waterquality(CatchmentsNewsletterIssueNo.9Winter2018).Thisisasubstantialissue in Co. Leitrim where there is a huge amount of existing forestry plantations and an ever increasingamountoflandsbeingpurchasedbyforestrydevelopers.Itwouldbebeneficial for Co. Leitrim if forestry locations could be managed as part of a national land managementplaninamoreintegratedmanner,especiallyasIrelandisrelyingonForestry plantationsto helpmeetitsEUCarbonreductiontargets.Forestryapplicationsshouldbe assessedusingacommonintegratedmethodologyappliedforallCounties,incorporating a pre-afforestation water quality check and proactive biology and chemistry monitoring during all forestry activities. Concerns have been raised regarding the existing system where the appeals system is adjudicated by the same department as the afforestation applications. Many of these forests are located in highland areas on peat on naturally acidic soils andin locations that should never have been planted. Forestryis asignificant pressure on water quality due to nutrient and sediment loss to waters, the impacts on biodiversity and acidification of waters. Mitigation solutions have been identified depending on the water quality impact; related to sediment loss, related to herbicide impacts, related to physical alterations of habitats. Herbicides are used to manage vegetation competition on some sites and further research into the mobilisation of such small quantities of herbicides is required. Particularly the herbicides attachment to fine sedimentintowatersisrequired;duetothesignificantimpactonwaterquality(especially drinkingwatersources)andthesignificantdistancesthatsuchparticlesremainprevalent. The Forest Service needs to play amore proactive role in controllingContractors etc and bufferzonedistancesshouldbeincreasedtoprotectwaterquality.Insomeoftheforests that were planted some 20-30years ago there willbe significant challenges when felling because no buffer zone, no riparian margin exists. Forestry guidelines from publications such as the “Forestry and Water: Achieving the Objectives and Priorities under Ireland’s River Basin Management Plan 2018-2021” need to be provided to the forestry owners, the Contractors with their felling licences and these guidelines should be strictly policed by the Forest Services staff on the ground during felling/thinning activities. The Forest Service shouldbecarryingoutregularinspectionstomakesurethatforestryactivitiesare incompliancewithplanting&fellinglicencesandnoactivitiesshouldbeallowedbetween 1st MarchandtheendofAugusteachyear,incompliancewiththeWildlife(Amendment) Act 2000 and the Heritage Act 2018. There should be major penalties imposed if water

quality is under threat/affected by forestry activities. Leitrim County Council working

closely with the IFIhas issuedSection 12Notices on ForestryCompanies in breach of the “Forestry and Water Quality Guidelines” andtheWaterPollutionActs.

8.

TheissueofPesticidesinDrinkingWaterisalarming.TheEnvironmentDepartment continuestoplayaroleindeliveringandnotifyinglandownersoftheirresponsibilities anddistributestheDepartmentofAgricultureleaflets.TheEnvironmentDepartment developeditsownpesticideflyerwhichcondensesallthenecessaryinformationinto a conciseflyer.Weareworkingwithcommunitygroups,TidyTowns,Hotels,Ianrod Eireann(PesticideSprayTrain)topromotebestpracticeguidanceandawarenessonthis issue.TheEPAselectedthisflyerfordisplayatitsannualNationalWaterEventthisyear; makingthisleafletavailablenationallyforalltheattendeesattheconference.MCPAin ouropinionneedsto bebannedbytheDepartmentthuscompletelyeliminatingtherisk ofthesepesticides.Furtherresearchisrequiredto understandthemobilisationof pesticidesinfinesediments,thechemicalattractions/mobilisationinfinesediment particularlyinpoorlydrainedacidicsoilsandrunofftotheneareststream/river/lake.

9.

InvasiveAlienSpecies–CurrentlytheNationalBiodiversityDataCentrerecordsthe presenceofInvasiveAlienSpecies.TheDepartmentofCulture,Heritageandthe GaeltachtandtheHeritageCouncilfundstheNationalBiodiversityDataCentreso itcan collateanddisseminatesurveillanceinformation.Muchmoreworkisrequiredanda NationaldatasetneedstobecompiledwithaLeadAuthoritysuchasInlandFisheries Ireland(IFI)ortheNationalParksandWildlifeServicewithresponsibilityandaccessto fundingfortheengagementofspecialistcontractorswho shouldbe‘licensed’bythe LeadAuthorityto treat,eradicateanddisposeoftheInvasiveAlienSpecies(IAS) appropriately.Thegeneralpublicdon’tknowwhoto reportthepresenceofInvasive AlienSpeciesto,aclearmessageidentifyingtheLeadAuthoritywithresponsibilityis needed.To supportgreaterpublicawarenessto locate,identifyandto stopthespread oftheIAS,an“IAS-App”orGIStoolforthepublicto identify/recordthelocationofthe IASshouldbedeveloped;IFI,anglingclubs,theCatchmentAssessmentTeams,Rivers Trusts allhavearoletoplayhere.EspeciallytheoccurrencesofJapanese Knotweed and Himalayan Balsam whichposethegreatestthreattoaquaticecosystemswhenpresent intheriparianzones. Potentially, InvasiveAlienSpeciesmaybeposingamuchgreater

problemandhavingamuchgreaterimpactonexistingwaterqualitybutinformationis

limited.

10. Slurryspreadingprovidesadiffusesourceofpotentiallyverypollutingmaterialwhichif appliedinappropriatelytendstofindanoverlandpathwaytosurfacewaterreceptors. Thesoiltype/capacity/suitability/weatherconditionsusuallymeanthattheslurrycan onlybespreadonthelandatthebackendofthegrowingseasonwithverylittle agriculturalbenefitgained.Itwouldbeaverybeneficialinitiativeforprotectingwater qualityintheWestofIrelandifanaerobicdigesterscouldbeusedinstead;possiblyan incentivisedpublicprivatepartnershipmodelcouldbeused. Suchanaerobicdigesters couldbesetupinpartnershipbetweentheinterestedpartiessuchastheESB,Bordna Mona(thepowergeneratingcompanies),IrishWater(who hasresponsibilityformassive tonnagesofsewagesludge),theAgriculturalslurry/sludgegeneratingCompaniese.g IPPClicensedpigandpoultrysuppliers,andotherorganicsludgeproducerssuchasdairy farmersonaregionalbasis.Avacuum tankercouldcollecttheslurryfromthefarmer’s slattedshedforthedigester.Theanaerobicdigesterwouldcreateenergyasaby.productforuseintheelectricitygridandtherebyincreasingtheamountofpower createdfrom renewableresourcesassistingwithIreland’sEUCarbonreductiontargets. Thepelletisedendproductcouldbecreditedbacktothefarmerbasedonthevolumeof slurrysuppliedasafertiliserproduct.Thisseemsto beamodelwhichisworkinginother EuropeancountriesandwhichIrelandshouldtryto advance,evenonapilotscheme basis.

Increasingawarenessandtrainingforfarmersshouldremainamandatorypartofany DAFMscheme.Particularlyinregardto theGAPRegulations,setbackdistances,the benefitsoffencingalongwaters, settingupproperdrinkersfordrinkinganimals, herbicide,pesticideandsheepdipuse,farmyardmanurestorage,plantingtheriparian zoneto breakthepathwayofslurry.Theseareallcommonactivitieswhichwillbenefit waterqualitywhencarriedoutproperlyandisamessagethattheDAFMcanhelpto communicatetoandwiththecontinuingeducationoffarmers.Itisimportantto highlightthesynergybetweenfarmingactivities,farmingpracticesandwaterquality.

AllfutureagriculturalschemesofferedbytheDAFMshouldbe“tailored”dependingon geographicallocation/soiltype/waterqualitystatus/annualrainfall,withaminimum acceptancecriteriathatsoiltestsarecarriedoutandnutrientmanagementplansare prepared.Futurenationalschemescannotproceedona“onesizefitsall”approachifwe

wantto strengthenthe‘protect’objectiveoftheRBMPs.NitratesDerogation

determinationsbyDAFMshouldtakeaccountofsource(drinkingwater)protection,and includeamethodologyforassessmentoftheimpactonwaterqualityandtheRBMP objectives. NutrientmanagementiscriticalfortheprotectionofwaterqualityonEPA licensedintensiveagriculturesites;theoutletsformanurecanchangepostgrantof planningandissuesarisefortheLocalAuthoritieswithtrackingmanuremovements.The controlsusedatsuchEPAlicensedagriculturalsitesformanuremanagementshould takeaccountofwaterprotection.

11. TheStakeholderengagementalreadycommencedduringthe2nd RBMPcycleby LAWPROandtheASSAPadvisersandLAWCOisplayingapivotalroleinengagement withourcommunities.Creatinganenvironmentofeducationandawarenessand assistingwiththesettingupofrivertrustswithinallourrivercatchmentareas.The continuationofthisworkisimportantduringthe3rdRBMPcycle,tocontinueto increasepublicengagement,participationandconsultationwithcommunitiesand stakeholders.

12.

InlandFisheriesIreland(IFI)staffareverywellplacedto protectfishstocksandensure waterqualityisnotimpactedbypotentialpollutionrisksandensuringno worksare takingplacewhichcouldbedetrimentalto waterqualityorwillimpactonfish,while also protectingtheanglingtourism product.

13.

Landslidescausehydromorphologicalmodificationstoflow,to thechanneldepthand width,to theriparianzoneadjacenttotheriver.Thisleadsto animpactonthephysical habitat,onfishlife,thedrainage,increasingthesedimentloadinthewaterbodiesandis asignificantpressureonwaterquality.Tightercontrolmeasuresandgreaterpenalties needto beimposedondevelopersorindustriesfoundto havecontributedtosuch events.Ittakesyearsforthewaterqualityofriversandlakestorecoverfrom theeffect ofthesehydromorphologicalchanges.

14.

AllWasteFacilitypermittedsitesorCertificateofRegistrationsitesespeciallyforC&D wastedisposalneedtobecarefullymanagedandmonitoredtoavoidanypollution threatonwaterqualityinlakesandrivers.Prominenceto thewaterqualitymessageis veryimportantinthissector.TheseFacilitiesshouldbepolicedregularlyandan EnvironmentalLiabilitybondshouldbeamandatoryrequirement.Thisbondshouldbe

maintainedbytheoperatorandifanoperatorgoesoutofbusinessitshouldcoverthe

costoftheremediationforthesite,thusavoidingtheriskofmajorpollutionsuchasoil contaminationetc.

15.

TheongoingCapitalProgrammefortheregenerationoftownsandvillagesandthe investmentprogrammeundertheFloodsDirectiveandCFRAMprogrammemustbe alignedwiththeRiverBasinManagementplansforthecountry.

16.

Surfacewaterdrainageintownsandvillageswhichreliesonapipednetworkwithan endofpipedischargetoanadjacentwaterbodycanplaceasignificantpressureon waterquality.BetterplanningforattenuationmeasureswhichincorporateSustainable UrbanDrainageSchemes(SUDs)shouldbemandatoryfordevelopers.Ashighlightedat therecentEPAnationalWaterEvent2020thereshouldbemorefocusbydesignerson “Blue-GreenInfrastructure” to attenuateandmanagesurfacewaterinourtownsand villages.Suchworkswouldoffertheopportunityforimprovedlandscapingtoenhance biodiversitythroughappropriateplantingimprovingtheoverallaestheticsofourtowns andvillages.ProperlydesignedSUDsschemesprovidesmultiplebenefitsnotjustto waterqualityandforreducingsedimentlosstowatersbutwillenhancetheappearance oftheopenandurbanareaswheretheyareused.Alongsidethisappropriatelylocated oil/petrolandgritinterceptionshouldbeincludedto supportsuchsystems.Thesetype ofSUDsschemesshouldbedesignedaroundgreeninfrastructure,biodiversityand climatechangetoprovideanimprovedmechanism tomanagetheincreasingrainfalland heavydownpours;nationalguidanceonSUDsshouldbeprovided.To complimentthe increaseduseofSUDsandfocusonbiodiversityitisalso timeforanobligatoryphasing outofthecurrentlevelofphosphatesandammoniainhouseholdcleaningproducts;this willrequireahigh-levelindustryagreementtoensurealevelplatform forallsuppliersof suchproducts.Avoluntaryagreementwillnotworktoeliminatethesechemicalsfrom theseproductsandtheremoval/reductionofthesechemicalswilldirectlyleadto an improvementinwaterquality.

17.

Thepublicareseekingto increasetheirleisureusageofourinlandlakesandare expressinganinterestinhavingsuchlakesdesignatedas“BathingWaterSites”.During the3rd RBMPcycle2022-2027asweachievetheobjectiveof“Good” statusinourwater qualitymoreofourinlandlakesmaybesuitableasbathingwaterlocations.Thereis

hugeworkinvolvedindeterminingifaBathingWatersiteissuitablefordesignationasa

bathingwaterlocation.Itrequirescarefulsiteassessment,andscientificassessmentto establishthebaselinewaterquality“Status” data.Maintainingthestatusofthese designatedBathingWatersandseekingadequatefundingforanyinfrastructural developmentsatsuchsitesisanongoingchallenge.Thepossibilityfordesignatingmore bathingwatersitesisapositiveconsequenceofwaterqualityimprovements.Thiswill also promotetourism,healthandwell-beingforallandwillcreateanassociated economicopportunityintheregions.

18. Significantchangetookplaceduringthe2nd RBMPCyclewiththeintroductionofthe LocalAuthoritiesWaterProgrammeCatchmentAssessmentTeam(LAWPRO)also known astheCatchmentAssessmentTeam.LAWPROisasisterorganisationtotheLocal AuthoritiesWaters&CommunitiesOffice(LAWCO).LAWPROandLAWCOarepartofthe LocalAuthoritiesWatersProgrammeOfficewhichisledbyKilkenny&TipperaryCounty Councils.Thereare5no.regionalCatchmentAssessmentTeams,with1no.Senior CatchmentScientistand6no.supportstaffineachregion.Weworkinclose collaborationwiththeCatchmentAssessmentTeamscoveringtheBorderandtheWest Regionswhoareworkingineachofthe10no.PriorityAreasforActioninCo.Leitrimto carryoutfurthercharacterisationlocallyto identifytheactivitiescausingtheproblem for eachindividualwaterbodywhichisidentifiedas‘AtRisk’ofnotmeetingtheirwater qualityobjectives.WeareworkinginclosecollaborationwiththeTeamtoanswer queriesfromthedesktopstudystage,providingthelocalknowledge,attending communitymeetingsandweworkwiththemonfollowupmeasuresastheyarise.In addition,weworkonanextensiveEPAWFDsamplingprogrammeontheLakesand RiversinCo.Leitrim.In2020thisprogram requires509samplestobecollected throughouttheyear.However,LocalAuthoritiesfaceanongoingchallengeto support andappropriatelyresourcetheongoingworkprogrammeandcollaborationsoutlined earlier,particularlywherefollowupactionsincludingpotentialenforcementwillbe requiredfromtheworkoftheCatchmentTeams.TheresourcingofLocalGovernmentin thisregardmustbereviewed,particularlyinthecontextofthecurrentstaffgrading structureswhencomparedwiththoseoftheLAWPROandLAWCOstructures.

19. Intheplanningforthe3rd RiverBasinManagementPlanCycle2022-2027;thetargets areambitiousandthereisasignificantamountofimprovementrequiredby2027. SignificantwaterqualitypressureshavebeenidentifiedandthenewResourceModel (LAWPRO)thatwasintroducedduringthe2nd RBMPcyclewillbecontinuedintothe3rd cycle,withthesestaffcontinuingto carryoutlocalinvestigativeassessmentsto identify wheretheproblem areasareinthecatchments.Itremainsabitunclearwhathappens afterthisprocessandwhatistheroleoftheResourceModel(LAWPRO)staff;willthey haveenforcementpowersundertheLeadAuthority(Kilkenny&TipperaryCounty Council).Timewillmarchquicklytowardsthe2027deadlineforthe3rd RBMPcycle.If enforcementactionisto betakenbytheexistingLocalAuthoritystaffinsteadof LAWPROthenthereisahugeresourcingdeficit.TheLocalAuthority’sstaffresourcesare currentlyunderhugepressureandchallengetodelivertheirexistingworkprogrammes andhaveno sparecapacityforadditionalenforcementwork.Itwouldappearvery ambitiousto haveallthestatusimprovementsinallthewaterbodiescompletedby 2027.Thereisconsiderableworkalreadyto“fix”thewaterqualitysignificantpressures thathavebeenidentified.However,itmustberememberedthatthereareotherwater bodieswheretheLocalCatchmentAssessmentworkisyetto start.To restorethewater qualityofthewaterbodieswherethesignificantpressureshavebeenidentifiedis dependentonfundingandtime.Theavailabilityoffundingfromvariousschemessuch asCapitalschemes,grantschemes,ruralenvironmentalprotectionschemesisessential. Also,suchimprovementworksaretimedependant,andtherecoverytimethatitwill takeforthewaterqualitystatusto berestoredto ‘Good’istoovariabletopredict. Asa result,therewillbemanyimprovementsachievedinwaterqualitybutthismaynot meetthefinal2027deadlineforthe3rd CycleoftheRiverBasinManagementPlans.

FinallywewouldliketoexpressoursincerethankstoourcolleaguesinthedifferentGovernment Departments,theEnvironmentProtectionAgency,theCatchmentAssessmentUnit,andalsothe LAWCOandLAWPROstaffworkingwithusonthisproject.

YoursSincerely

VincentDwyer, HeadofFinance, Finance,Water,Environment,ClimateActionandEmergencyServices

From: Eamonn Farrell

Sent: Thursday 6 August 2020 19:39

To: rbmp

Subject: ICOS -Irish Co-operae Organisan Society.

Aachments: 07.08.20 SWMII ConsultaCOS_Final.pdf

Dear Sir/Madam:

Please find aached a response to the Significant Water Management Issues in Ireland Public Consultan by the Irish Co-operae Organisan Society. Kind Regards, Eamonn Farrell

Agri Food Policy Execue Irish Co-operae Organisan Society Ltd

&

Secretary, Milk Quality Ireland Co-operae Society Ltd

E. & O.E. Private, Confidenl and Privileged. This e-mail and any files and aachments transmied with it are confidenl and/or privileged. They are intended solely for the use of the intended recipient. The content of this e-mail and any file or aachment transmied with it may have been changed or altered without the consent of the author. If you are not the intended recipient, please note that any review, dissemina, disclosure, altera, prin, circulan or transmission of this e-mail and/or any file or aachment transmied with it, is prohibited and may be unlawful. If you have received this e-mail or any file or aachment transmied with it in error please noy ICOS at the above address.

SWMI Consultation, Water Advisory Unit, Department of Housing, Planning and Local Government, Custom House, Dublin 1, D01 W6X0

rbmp@housing.gov.ie

7th of August 2020

Re: Significant Water Management Issues in Ireland

To whom it may concern,

The Irish Co-operative Organisation Society (ICOS) is pleased to contribute to this important public consultation on water quality management in Ireland.

ICOS is the umbrella body for over 130 co-operatives in Ireland – including the Irish dairy processing & milk purchasing co-operatives and livestock marts – whose associated businesses have a combined turnover in the region of €14 billion, with some 150,000 individual members, employing 12,000 people in Ireland, and a further 24,000 people overseas.

The ICOS submission will focus on the three questions related to the agriculture chapter in the public

consultation document “Significant Water Management Issues in Ireland”.

How can the agricultural sector contribute towards improving water quality?

The Irish agri-food sector is responsible for annual exports worth over €14.5 billion, with dairy sector exports valued at €4.4 billion and livestock exports valued at €3.9 billion. The agri-food sector is Ireland’s largest indigenous industry responsible for the creation of sustainable jobs and employment across the rural economy. As integral members of Ireland’s export led economy, ICOS members are

acutely aware of the importance of sustainability and the challenges that face the sector. Our

members are founders of Origin Green, Bord Bia’s pioneering food and drink sustainability

programme. Our members are food processors, operating in extremely competitive global markets with international customers increasingly focused on sustainability, in addition to ensuring the highest quality and safety standards. Ireland has successfully built a reputation for a producer of sustainably produced dairy and meat production. The agri-food sector has a vested interest to ensure Ireland’s water quality is improved to the highest possible standard. We believe that it is in everyone’s interest to work together to improve Ireland’s water quality and the dairy sector in particular is committed to working closely with farmers and with Government in a collaborative manner to protect water quality and our reputation as sustainable and safe producers of high-quality food.

ICOS members are key stakeholders and funders of the Agricultural Sustainability Support and Advisory Programme (ASSAP). ICOS as a representative body participates at the Farmer Consultative Group of ASSAP chaired by Teagasc. The ASSAP programme is an important new approach that enables farmers to engage positively in seeking solutions to local water quality issues with the support of a confidential advisory service. The main dairy processing co-ops have employed an ASSAP advisor to compliment the scientific work carried out by the LAWPRO team. The co-op ASSAP advisor provides a free, confidential and voluntary advisory service to farmers in the Priority Areas of Action. The co.op ASSAP advisors provide farm specific assessments and plans to prevent the loss of nutrients and sediment from entering waters. The co-op ASSAP advisors also play a key role in disseminating key water quality messages to their wider member suppliers through farmer meetings, newsletters, text messages, social media platforms, videos and webinars.

The dairy processing co-ops also run joint programmes with Teagasc, with some in operation for more than 20 years. The joint programmes are farm development programmes, which seeks to address technical improvement, with environmental stewardship now central pillars of each programme. The co-ops also run a series of pilot farms under the dairy sustainability initiative to demonstrate best practice to their suppliers in the area of soil health, soil pH, nutrient management, farmyard management, slurry management and application.

These are practical examples of measures the agriculture sector and the co-op sector in particular are contributing to better water quality. The co-op sector as businesses owned and controlled by farmer members have demonstrated a strong commitment to their supplier base by supporting a range of technical programmes including ASSAP. This commitment will continue into the future across all aspects of environmental sustainability including water quality. We emphasise the importance of addressing issues such as water quality in a collaborative, whole of government and whole of sector approach. This method will deliver greater environmental outcomes, while sustaining economic activity in rural Ireland.

Do you believe that CAP will have a positive or negative impact on water quality in Ireland?

The Common Agricultural Policy (CAP) has played a positive role in improving water quality in Ireland.

The European Commission’s evaluation of the CAP’s impact on water quality published in 2019

concluded that the CAP has participated in raising awareness on water issues and put the topic of water higher on the agenda.

In Ireland, the CAP has supported improved water quality through environmental and investment programmes under rural development measures. The Green Low Carbon Agri-Environment Scheme (GLAS) is a targeted agri-environment scheme under the Rural Development Programme. Prioritisation of farms within vulnerable catchments and ‘high-status’ waterbodies is a key feature with 45% of GLAS actions benefiting water quality.

The Targeted Agricultural Modernisation Scheme and its predecessors has been instrumental in supporting on-farm investment in new slurry storage, farm buildings and novel machinery such as trailing shoe technology. Specifically, there are two TAMS schemes benefiting the protection of water: The Animal Welfare, Safety and Nutrient Storage Scheme and the Low Emission Slurry Spreading Scheme. These investment schemes have undoubtedly contributed to improved environmental and water quality outcomes. The continuation of a well-funded TAMS programme under the next financial period from 2021-2027 is critically important to ensure continued improvement and outcomes at farm level.

In addition, the cross-compliance framework includes statutory requirements related to water protection and management arising from the implementation of the groundwater directive and nitrates directive, as well as GAEC standards.

The CAP Reform process for the period 2021-2027 is still under negotiation with at least a two-year transition period envisaged. However, it is evident that the new CAP framework will result in an even greater emphasis on the environment. Under Pillar 1 of the new CAP, Member States will have to design eco-schemes, which is a new requirement. The development of eco-schemes should operate in conjunction and compliment new agri-environmental and investment schemes under Pillar 2.

We emphasise the importance of developing a new environmental scheme under Pillar 2 that will encourage greater participation by dairy farmers with a focus on measures that will have co-benefits for climate, water, soil and air. We also emphasise that the CAP cannot do everything. The CAP provides vital income support to thousands of farm families, underpinning food security and the provision of positive public goods. However, the CAP is one of the most important tools to bring targeted change. A good environmental scheme, supplemented by practical, well designed, farmer friendly eco-schemes will be important.

Finally, the new CAP must continue to support productivity and efficiency at farm level. Ireland’s grass based, sustainable production system is key to our efficiency and low-cost production. The TAMS programme is key to supporting farm investment, environmental improvement, animal welfare and health & safety and must be continued under the new CAP.

Do you think CAP measures to protect water quality should be retained at a national scale or become more locally targeted?

The best approach will involve national measures combined with locally targeted measures. The Agricultural Catchments Programme (ACP) has a cumulative 10 years of water quality monitoring set

up to assess compliance with the nitrate’s directive. The ACP involves 320 farmers across 6

catchments. Each catchment has different soil and farm types with P loss a greater issue on heavy clay soils and N loss a greater issue on free draining soils. N & P contrast significantly with mitigation measures different as a consequence. In summary, soil type, weather and farm practice will all have a bearing on water quality so the more targeted the measure can be, the better the likely outcome.

The ASSAP programme is an example of a locally targeted approach, with individual farm assessments carried out under three categories: land management, nutrient management and farmyard management. The ASSAP programme through scientific work conducted by LAWPRO has identified the main pressures on water quality in each PAA. This information can be used as a basis for preparing mitigation plans for farmers designed to help improve water quality. The scientific work conducted by LAWPRO has concluded that sediment loss is a greater pressure on water quality than previously considered, which is an important learning.

The combined approach between national and locally targeted measures could be provided for under the new CAP eco-schemes, with ICOS proposing that farmers should be provided a menu of options with mitigation measures appropriate depending on the water quality pressure at local level, whether it’s P, N or sediment. This is the approach we have supported at the CAP consultative committee established by the Department of Agriculture, Food and the Marine.

The ASSAP programme has identified a range of mitigation options with the ASSAP Interim Report published in 2020 highlighting 20 mitigation actions for farmers including preventing P loss through overland flow, NMP planning, buffers, drinking & stream fencing, organic manure location and method etc. These options are discussed with the farmer and appropriate action is selected. These 20 mitigation measures should be examined including barriers to their adoption. The CAP should provide appropriate support to farmers involved in implementing these mitigation measures, especially measures where cost is a barrier.

****************

We look forward to engaging constructively and positively with both the Department of Housing, Planning and Local Government and the Department of Agriculture, Food and the Marine on the important issue of water quality. We re-emphasise that it is in everyone’s interest to work together to improve Ireland’s water quality. The dairy sector is committed to working closely with farmers and with Government in a collaborative manner to protect water quality and our image as sustainable and safe producers of high-quality food.

Yours sincerely,

Mr. Jerry Long

President, Irish Co-operative Organisation Society

From: Mary Gurrie

Sent: Thursday 6 August 2020 12:17

To: rbmp

Subject: EPA

Aachments: SWMI_submission_EPA_Aug2020.pdf

Hello Mick

Please find aached the EPA’s submission on the SWMI consulta. Kind regards Mary

From: rbmp <rbmp@housing.gov.ie> Sent: Friday 20 December 2019 17:04

Subject: Consultan on the Significant Water Management Issues now live Importance: High

Dear all,

I am pleased to announce that the consultan on the Significant Water Management Issues (SWMI) for Ireland has now been published on the Departments website at

hs://www.housing.gov.ie/water/water-quality/water-framework-direce/public-consultanificant-water.

management

While a formal launch and further media acadverg is planned for the new year, please feel free to circulate to any interested par.

Thanks and enjoy the Christmas break.

Regards, Mick

——

Michael McBride

Water Advisory Unit

——

An Roinn Tithíochta, Pleanála agus Rialtais Áitiúil

Department of Housing, Planning and Local Government

Teach an Chustaim, Baile Átha Cliath 1, D01 W6X0

Custom House, Dublin 1, D01 W6X0

http://www.housing.gov.ie

——

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Deimhnítear leis an bhfo-nóta seo freisin go bhfuil an teachtaireacht ríomhphoist seo scuabtha le bogearraí frithvíorais chun víorais ríomhaire a aimsiú.

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SWMI Consultation Water Advisory Unit Department of Housing Planning and Local Government Custom House Dublin 1 D01 W6X0 06 August 2020

Re: EPA Submission on the Significant Water Management Issues in Ireland Consultation

Dear Sir/Madam

The Environmental Protection Agency (EPA) welcomes the opportunity to comment on the Significant Water Management Issues in Ireland (SWMI) Public Consultation Document. As you know the EPA has a specific role under legislation in providing scientific and technical assistance to the Minister in developing the programme of measures and this work is on-going to support the preparation of the draft River Basin Management Plan 2022-2027. The EPA also has a role in advocating that the key environmental challenges facing Ireland are addressed and it is in this context that this submission is made.

We welcome the publication of the SWMI in line with the 3rd cycle planning timeframes and the opportunity for public engagement which is a key component of the Water Framework Directive. We welcome also the recognition that all sectors must play their part in protecting and improving Ireland’s water resources, and that ensuring consistent policy integration across the River Basin Management Planning Process with other national and local plans is a key priority.

The EPA’s Water Quality in Ireland Report 2013-2018, published in December 2019, found that water quality had declined after a period of relative stability and improvement. Only 53% of surface water bodies are in satisfactory ecological condition. We reported an increase in the number of the most polluted river sites, and an increase in the number of rivers in poor ecological health. Positive trends reported previously by the EPA had reversed. Not only have we failed to improve overall water quality, we are also failing to prevent further deterioration of our rivers. The Water Quality Report made clear the challenges that face Ireland in achieving good water quality status. While there have been improvements, an additional 400 water bodies are now not meeting their targets. It is essential that we halt both the declines in water quality and continue to prioritise work to restore waters to at least good status.

It is widely accepted that the first River Basin Management Plan (2009-2015) did not deliver the projected improvements in water quality. It appears at this stage that the second River Basin Management Plan (2018-2021) will also not deliver the scale of improvements required. It is therefore essential that this next River Basin Management Plan delivers on real and sustained water quality improvements.

Notwithstanding the water quality results, the EPA notes that substantial progress has been made under the second cycle in establishing the new governance structures, the LAWPRO/ASSAP programme and the Community Development Fund. We need to build on this progress to further embed the integrated catchment management approach, and to expand and target the programmes of measures developed for the second cycle plan. Progress has also been made in areas such as forestry, peat rehabilitation and in developing the evidence base on hydromorphology. We hope and expect that these measures will soon start to deliver in terms of actual improvements in water quality.

Some areas however require urgent and increased attention and action; the increasing nutrient levels particularly nitrogen from agriculture, the rate of delivery of the required wastewater infrastructure, impacts from drainage works, addressing and mitigating the impacts of climate change, and the on-going declines in our high status objective (HSO) water bodies.

Agriculture

Agriculture is the sector with the most widespread impact on water quality in Ireland, impacting on almost 800 waterbodies at risk of not achieving their WFD objectives. The water quality issues arising from agriculture include excess nutrients, the loss of fine sediment, chemicals (pesticides and herbicides) and microbiological pathogens (e.g. VTEC) from animal faeces entering waters causing a risk to aquatic life and human health.

The scale of the challenge ahead for the agriculture sector is significant; the environmental indicators for water quality, air quality, greenhouse gases and biodiversity demonstrate that we are not meeting our environmental targets, and that the trends are all going in the wrong direction at present. It is essential that we take the steps needed to halt the current declines and begin to reverse the trends.

A significant number of plans and strategies have recently been published, or are in development, which point towards the need for changes in farming practices to meet our environmental targets. These include the Farm to Fork strategy, the EU biodiversity Strategy, the CAP strategic plan, the 5th Nitrates Action programme, the 2030 Agri-food strategy and the Climate Action Plan. An opportunity now exists to align these policies and strategies to ensure that any measures to address water quality can deliver multiple benefits including reductions in greenhouse gas and air pollutant emissions, and enhanced biodiversity. Additional benefits may also include natural flood mitigation and amenity values that can support improved health and wellbeing.

Nutrient pollution from agriculture is the most prevalent water quality issue. The manner in which nitrogen and phosphorus emissions to water arise, and their impact in the water environment, varies with catchment, soil type and farming activity. This means the messaging, supports and policy responses for achieving water quality improvements need to become more targeted and specific to the local environmental issues and setting, and we need to find ways to better support and engage farmers to embrace and implement the practice change that is needed. The principle of ‘the right measure in the right place’ should be further emphasised in the 3rd cycle plan. In addition, there needs to be an emphasis on ensuring optimum use of organic manures as per Teagasc advice, and an overall reduction in the use of mineral fertilisers, as called for recently in the Farm to Fork strategy.

Wastewater

Waste water (urban and domestic) is the second most prevalent significant pressure impacting on water quality generally, and the most significant pressure impacting on bathing waters and shellfish waters. The serious challenges facing Ireland’s water environment and water/wastewater treatment infrastructure are reported extensively in our most recent Drinking Water, Urban Waste Water Treatment and Water Quality Reports. Irish Water will not now deliver on the targets set out in the second cycle and unsatisfactory progress has been made to date, particularly in addressing sole significant pressures.

Establishment of, and infrastructural and operational improvement to, waste water facilities must be progressed at a much faster pace. Continued investment is also needed in the upgrade of combined drainage systems, storm water overflow devices and extending collecting systems. Funding and investment in water services should be aligned with the specific priorities of the RBMP nationally and within the Priority Areas for Action.

Climate

Climate change is a significant threat to water quality, water quantity and water services. These challenges are clearly set out in the Climate Change Sectoral Adaptation Plan for the Water Quality and Water Services Infrastructure Sectors. The national attention and focus on climate mitigation and adaptation presents an opportunity to achieve benefits for water quality and water resources and conversely water quality measures under the RBMP can be key climate measures.

The potential role of climate to interact with all the significant pressures needs to be considered and all measures under the plan should be climate proofed. Funding of research on the interface between water and climate should continue to be supported and funded.

With climate change, and a growing population placing increased pressure on water resources the implementation of an effective regulatory regime for abstractions is essential to manage these risks. The two significant periods of dry weather in 2018 and 2020 have highlighted the importance of this measure. We recommend the proposed legislation should be progressed without further delay.

Physical changes to rivers

The evidence base from the characterisation process and the work of LAWPRO illustrates that hydromorphological pressures have a widespread and significant impact on the condition of our waters, yet they are currently poorly managed. Key pressures include land drainage, channel maintenance and dredging, removal of riparian vegetation, excessive use of hard engineering, and barriers which restrict flow, fish migration and sediment transport.

The 3rd cycle plan should strive to develop and implement better management and enforcement of appropriate measures to restore and improve the hydromorphological condition of waters. The work being carried out by the Department to develop guidance for bringing the WFD into the planning framework should be progressed and implemented as a matter of urgency. This work needs to be widely disseminated and appropriately resourced so that it can be implemented in full. Strong leadership will be required to improve cooperation across the range of public bodies that are involved, and to accelerate and drive the work forward.

The links between the objectives of the Floods Directive and the WFD need to be strengthened in the 3rd cycle plan. A greater emphasis should be placed on reducing potential impacts of flood defence works on hydromorphology and ecology. Implementing natural water retention measures throughout whole catchments (‘slowing the flow’) should play an important role as these measures can reduce flooding, prevent sediment and nutrients reaching waters, and can provide wetland habitats for a range of species thereby improving biodiversity.

High status water bodies

Only 20 of our highest quality river sites now remain and the trend is going in the wrong direction. Securing funding for the Waters of LIFE project has been a success under the current cycle however by its nature it will be limited in the number of water bodes which will benefit. The establishment of the Blue Dots Programme is also welcome however in order to be in a position to make any substantial improvements and to halt the declines this programme will need to be adequately resourced. High status waters are particularly sensitive, so prevention is better than cure. There should be an increased and urgent focus in the third cycle plan on protecting the remaining high status waters. Sediment losses from forestry operations in upland catchments is the most significant pressure impacting on our high status waters. There needs to be on-going focus on ensuring the full implementation and enforcement of the environmental requirements for afforestation and an increase in the level of oversight when operations are planned in high status catchments.

The outcome of the EU WFD fitness check is that the Directive is fit for purpose and that the focus should be on improving implementation. The 2027 deadline for achieving at least good status in all waterbodies is an extremely ambitious target which will be very challenging to meet. It is nevertheless an important target that is needed to underpin a sustainable, vibrant, healthy economy into the future. Primary legislation to fully implement the directive is required to put attainment of the objectives on a firm legal standing and should be prioritised in this cycle.

Achieving our Water Framework Directive objectives will require leadership, ambition, investment, and an integration of policy across departments and sectors. Significant progress has been made in the second cycle in establishing structures which promote knowledge sharing and collaboration. Collaboration between the public and private sectors, and greater engagement and involvement of communities will be essential. The EPA is committed to working with the Department and stakeholders within the governance framework and will play its part in contributing to achieving this important goal.

We have included specific comments in relation to some of the other SWMI issues and suggestions for potential measures in Appendix 1 below.

Dr Micheál Lehane Director, Office of Evidence and Assessment

Appendix 1

Prioritisation

There are early indications that we are achieving improvements in water quality in the Priority Areas for Action (PAA). The EPA therefore supports the continuation of the prioritised approach for restoration of water bodies. The gains being made in PAAs however were offset by sometimes significant deteriorations in water quality in other areas and that needs to stop. A key objective of the WFD is to prevent deterioration and the basic measures in place do not appear to be achieving this. There is a need to greatly enhance the protect function under the next RBMP so that the investment and effort in securing improvements in PAAs delivers on a national scale and to cease or mitigate activities that are causing the declines.

There is also a need to scale up learnings made in funded projects, pilots and schemes to a national level. There is potential to optimise the resources involved and maximise the outcomes by better integrating, coordinating and consolidating the efforts being made by implementing bodies, communities, research and other funded programmes, to protect and improve water quality in each catchment.

In selecting measures, priority should be given to actions that achieve multiple benefits for as many of our environmental assets as possible (i.e. air quality, greenhouse gases, biodiversity, natural flood mitigation and water quality), as well as supporting our economic and social goals.

Public Participation

The EPA welcomes the significant improvements in the level of public engagement in water related activities in the current cycle and the efforts and resources put in place to encourage public and community participation. There are a number of areas which should be developed further or supported to continue to build on the progress made. The role of An Foram Uisce in raising public awareness and engagement could be enhanced. Further opportunities could be sought to establish and support Rivers Trusts and other community groups to help put themselves on a solid foundation. Learnings from the experiences of the Maigue and Inishowen Rivers Trusts in the coming years will provide valuable insights in this regard.

Citizen science is an effective way of both engaging and educating the public and communities and in producing valuable scientific data. Consideration should be given to supporting the development and rollout of a National Citizen Science Programme or Strategy for Water which integrates and delivers a range of tools suited to all levels. An accompanying plan should also be put in place to allow for the safe collection, storage and dissemination of these data, as a valuable source of knowledge to support the wider aim of protecting and maintaining our waters.

We have made significant progress during the 2nd cycle plan in sharing data, knowledge and experiences widely and this should be continued over the course of the new plan. The public interest in environmental issues, particularly in the younger generations, is continuing to grow. Opportunities to increase awareness of the integrated catchment management approach and the value of good water quality, through community education programmes, professional development courses and academic institutions should be explored.

Planning

Effective and coherent planning at local, regional and national levels is key to delivering the environmental improvements required in both water, climate, air and biodiversity and to optimise the potential for multiple benefits from any measures taken.

The planning system should be used to ensure the delivery of nature-based and natural water retention measures as solutions for flood protection, the wide spread role out of green and blue infrastructure and sustainable urban development schemes and the protection of water resources through implementation of water efficiency measures. We agree with the statement in the SMWI that future infrastructure needs to be ‘WFD-proofed’.

Domestic Wastewater

The recent extension of the Domestic Waste Water Grant Scheme is welcome. The findings of the National Inspection Plan Implementation Report 2019 that over half of DWWTS inspected fail to meet the necessary standard and that 27% of systems that failed during 2013–2019 had not been fixed is a concern given these inspections are targeted at areas where DWWTS are most likely to impact on water quality. More action is needed to ensure that householders fix systems that fail inspections and to improve overall public awareness to encourage good practice.

Public Health / Drinking water quality

Water is vital for life but also can present a threat to health from exposure to contaminated drinking water, bathing water and shellfish. Issues such as microbial and nitrate contamination of groundwater, the incidence of VTEC in Ireland and the continuing detection of pesticides in waterbodies are of concern.

In the recent report on Drinking Water Quality in Public Supplies in 2019, the EPA highlighted the need to take a drinking water safety plan approach to assess risks to drinking water and to prioritise action to address the greatest risks. As the application of such a risk-based approach is likely to be included in the revised Drinking Water Directive, the next River Basin Management Plan should integrate drinking water safety planning into its application of the Integration Catchment Management approach and progress measures on drinking water source protection. Private water supplies continue to lag behind public supplies in terms of compliance and addressing private supplies should be considered in the programme of measures under the next RBMP.

The EPA agrees that all the measures identified in this section of the SWMI document are required. It is essential that enough resources are provided to progress these. The resilience of water supplies to extreme weather events also needs to be improved.

We need to continue to build our knowledge and evidence base in relation to public health aspects of water protection in areas such as VTEC, anti-microbial resistance, and combined effects of chemicals. A study on the economics of source protection versus treatment should be carried out. The EPA is completing its review of Nutrient Sensitive Areas as required by the Urban Waste Water Treatment Directive. These areas need to be placed on a statutory footing to ensure a high level of protection.

The benefits to health of improving water quality as well as access to blue spaces for wellbeing could be highlighted more and measures to promote and develop this aspect should be considered.

Invasive Alien Species

Invasive alien species are a threat to Ireland’s water quality, protected habitats and biodiversity and a cost to the economy. The National Biodiversity Action Plan highlights that the occurrence and spread of invasive alien species in Ireland is increasing, and that the impact of invasive species on Ireland’s protected species is expected to increase over the next decade. Several of the invasive species of concern are aquatic species or colonise riparian habitats. Invasive species impact ecosystems and may out-compete native species, leading to a loss of biodiversity.

An interim review of the National Biodiversity Action Plan 2017-2021 published in 2020 highlighted that there has been limited progress in tackling invasive species. The EPA agrees with the call in the SWMI for a strategic approach to this issue and that a coordinated approach among public bodies and stakeholders is required. An action plan is needed that is adequately resourced and supported. Strong leadership will be required to progress the relevant actions in an integrated way. Opportunities for engaging citizens through citizen science initiatives should be explored.

Hazardous Chemicals

While the overall chemical status of our water bodies is relatively good (when the ubiquitous substances such as mercury and polycyclic aromatic hydrocarbons or PAHs are excluded) the growing range and increasing levels of hazardous chemicals being detected in waterbodies is a significant concern from both an ecological and human health perspective.

The regulation on the manufacture, use and disposal of chemicals across all sectors (healthcare, animal health, agriculture, personal care products etc) is, by its nature, fragmented. Coordination in the development and implementation of plans and measures between the relevant authorities and organisations should be strongly promoted. The establishment of the National Aquatic Environmental Chemistry Group is a positive step in this regard and should continue to be supported. Similarly the National Pesticides in Drinking Water Action Group should continue to be supported.

There are several strategies and action plans which have recently or will shortly be published and which should be considered/implemented in terms of measures. The EU Biodiversity and Farm to Fork Strategies set out ambitious targets for reductions in pesticide usage. Ireland’s National Action Plan (INAP) on antimicrobial resistance is currently being prepared for the period 2021 to 2024. The proposed EU Strategy on the Sustainable use of Chemicals will likely include measures to increase awareness and influence behaviours in terms of chemical management (including medicines). The European Union Strategic Approach to Pharmaceuticals in the Environment (COM(2019) 128) provides a useful overview of the sources and potential measures which could be taken, many of which could be applied to the broader range of chemicals such as awareness raising, producer responsibility initiatives, and improved management of waste. In addition, the European Commission has recently launched a review of the directive which regulates the use of sewage sludge in agriculture. This review identifies that the directive fails to regulate a range of potential pollutants in sludges which can impact on soil and waters when spread on land. The outcome of this process will be relevant in terms of introducing additional measures to reduce the impacts of chemicals.

Monitoring for priority substances and priority hazardous substances is expensive. Additional monitoring is needed but it is important that it is targeted to ensure best use of resources. Opportunities should be explored to capture where the sale, use and disposal of pesticides and animal health products is taking place, so that they can be linked to local water quality impacts, so that we can improve our risk assessment processes. The findings and recommendations from the Disposal of Unused Medicinal Products (DUMP) Study should be examined and consideration given to the setting up of a PRI scheme to address the lack of a clear disposal route for unused pharmaceuticals. Investment into research on the risks and treatment technologies for hazardous substance should be supported to continue to inform policy and identify solutions.

Urban Pressures

Urban aquatic environments in our cities and rural towns are frequently characterised by unsatisfactory water quality. The types of pressures in these environments include runoff from paved surfaces, leaks and spills, misconnections where domestic discharges are piped straight to the river, unlicensed discharges, storm water overflows, and hydromorphological pressures such as culverts, barriers, modifications to the riparian zones, ports and harbours. These pressures can have impacts on ecological status, on the quality of waters used for industrial and drinking water purposes, and on bathing waters. Urban issues are typically challenging to disentangle and costly to mitigate.

Irish Water are currently progressing development of a number of drainage area plans which will map and assess the condition of the existing drainage network in 44 urban areas. Progress with this work is time consuming and slow. Significant future investment will be needed to implement the mitigation measures identified in those plans.

Consideration should also be given through the planning framework to how green and blue infrastructure can be retrospectively integrated into the existing urban environment, and progressively embedded in future in conjunction with new development applications. Although this is being progressed in some local authorities, opportunities should be explored for leadership and sharing of knowledge and experiences throughout the Local Authority sector. A strategic approach to river restoration in urban areas will likely be needed to ensure that multiple benefits are being targeted, so the best return on the investment is being achieved. As well as environmental benefits the potential public health and wellbeing value of green and blue spaces in urban environments has been highlighted in recent research by the Economic and Social Research Institute.

The issue of domestic misconnections is significant as addressing them retrospectively is very resource intensive, time consuming and costly. Creative mechanisms should be identified for preventing the problem at source, for example through an information, education and awareness program for landholders and contractors, a certification scheme, planning enforcement, or by other means. The learnings from the Dublin Urban Rivers LIFE project may be helpful in this regard.

Any further comments

The EPA is aware of concerns arising in relation to topics such as aquaculture, commercial sea-weed harvesting, anti-microbial resistance, microplastics etc. It is important that the risks and impacts of activities, whether existing or new, are identified, assessed and communicated and that we continue to both build the evidence base in relation to such topics and scan for future issues or topics which may be of concern.

From: Dungarvan Shellfish Ltd <dsf-oysters@hotmail.com>

Sent: Wednesday 5 August 2020 12:57

To: rbmp

Subject: Dungarvan Shellfish Ltd

Aachments: SWMI Submission.docx

Hi,

I hope you are well, please find aached our submission. Also, can you acknowledge receipt of our submission. Many thanks, Ita Harty

Please note that we cannot guarantee that any personal and sensitive data, sent in plain text via standard email, is fully secure. Customers who choose to use this channel are deemed to have accepted any risk involved. The alternative communication methods offered by us include standard post.

Re: Significant Water Management Issues (SWMI) public consultation document

TowhomitConcerns,

Wewouldliketoaddthebelowsubmissiontotheconsultationprocess.

Shellfishgrowing areaswere previouslyprotected under The Shellfish Waters Directive which was subsequently subsumedinto the Water FrameworkDirective(WFD) whereupon the guideline microbiological(fecal coliforms) value in shellfishgrowingwaters wasdropped altogether. Thus, theWFDwhichShellfishproducersrelyupon forprotection does notprotect against pollution by sewagefrom humans and agriculture whichhas anegativeimpacton the receiving environment andin particular to shellfishproducers.

Amandatory value (upperlimit)forE. coliin theshellfishgrowingwaters shouldbe established to protect shellfishproducers akinto protectinghumans in bathing waters. Ecoli wouldbethe most relevant asShellfishProduction areasareclassifiedbasedon Ecoliinshellfishflesh.

Adherenceto amandatoryvaluewould also havetheaddedbenefitof reducing norovirus (human sewage derived)levels presentin thewater column allowingforeasierdepurationof shellfish(oysters) andindeedlongerperiodsoftheyear whenoystersare naturallyNorovirus free. Afurther benefitof adheringto anE. coli water limitby reducinghuman and agricultural discharges is that nutrientinputs are reduced also (Nitrogen andPhosphorus come withtheE. coliin these discharges). Norovirus legislationis imminent andis acrucialparameter forthe shellfishindustry andthe shellfishindustry shouldbeprotectedfrom highlevelsof norovirus inputfrom humansewagedischarges under the Water FrameworkDirective.

This is asignificantwatermanagementissuethatisnot addressedbythis consultation draft. Microbiological standardsin waterbodies needto be enshrinedin the waterframework directive for thegoodofthe shellfishindustry, the public using waterbodiesandthe ecosystem. Pollution Reduction Programme’swhichweredevelopedfor ShellfishDesignatedWaterbodies seem to have haltedin their development.Whyis thisso?

Furthermore,theWFDdoes notmonitor allthe necessaryparametersto protectthe ecosystem in TransitionalandCoastalWaterbodies. An exampleofthis wouldbethe largescale and widespread useof chlorine-basedbleachese.g. Sodium Hypochloritesuch as usedto control biofoulingin powerstations using seawater intakefortheir cooling systems, in agricultural practices(cleaningoutoftanks), foodprocessingbusinesses andpotentiallyinsewage networks,sewage holdingtanks andtreatmentplants. The inputofbleaches suchas Sodium Hypochlorite into themarine environment leads to complex chemical reactionswhich can lead to the formation ofChorine ProducedOxidants(CPO’s) e.g. hypobromous acid,hypobromous ions andbromaminesandultimatelyto longerlastingTrihalomethanes e.g. Bromoform inthe marineenvironmentwhichcan impacton phytoplankton production andothermarine life (lethal and sublethal effects). The recognitionthatCPO’s aredamagingto marine life and ecosystems hasmeantthatCPOthreshold values havebeen setin countries e.g. SouthAfrica, Canada andthe USAwithlevelsset at2-10micrograms/Lofseawater.TheWaterFramework Directivedoes not appearto addressthese parameters ortheireffectson theecosystem inthe marineenvironment.

However, one canseein this consultation documentthatthereare procedures inplace and bodies taskedwith addressingthese shortcomings:

. The National Aquatic Environmental Chemistry Group (NAECG) was established to bring together national expertise on hazardous chemicals in the aquatic environment, and to bring a new smarter strategic approach to the management of hazardous chemicals in the aquatic environment into the future

. A national monitoring programme for priority and specific substances has been

established. The programme is evolving to accommodate new compounds, which may be added at either EU or national level.

. The EPA will continue to review and develop its analytical capabilities for assessing hazardous chemicals in Irish water bodies to take account of any new priority and priority hazardous substances specified by the Commission or new specific pollutants identified specifically for Ireland

So,itwouldseemthatthewayiscleartoaddressthemonitoringandimpactofbleachand bleachderivedintermediatesandendproductsinthemarineenvironment.Indeed,theinsecticide cypermethrinwasrecentlyaddedtotheWFDmonitoringprogrammeinIreland(asstatedinthe consultationdocument).

. More recently, a scoping study carried out by the EPA in 2017 – 2018 detected the

presence of the insecticide Cypermethrin in rivers at multiple locations across Ireland and this substance has recently been added to the national monitoring programme.

The emphasis intheWaterFrameworkDirectiveis to avoid unnaturallyhighlevelsof phytoplankton intransitional and coastalwaterbodies(eutrophication)whichisveryimportant but suppressionofphytoplankton production unnaturallyby anthropogenic chemicalssuch as sodium hypochlorite is also importantto avoid asall ofthe ecosystem is dependent on phytoplankton for sustaininghealthy and stablemarine life populationsand services.This is particularlyimportantfor shellfishproducerswho aredependenton phytoplankton levels reasonableenoughto sustain growthandhealthof stockto market size.

The draftconsultation paper statesthatthere are concerns regarding aquaculture and needsto be investigatedfurther andfor shellfishfarming:

. In relation to shellfish farming the main concern related to the potential for contamination of shellfish arising from land-based activities, particularly wastewater discharges.

This is wordedas to presenttheshellfish asthe problem rather thanthe land-based activity whichis truly remarkable for allthewrong reasonsgiven the largescale andwidespread discharges enteringtransitional and coastalwaterbodies andgiven theverylong-standing presenceofasustainableworld class shellfishindustryin thesoutheastofIreland.

Shellfishfarmingis unique in thatitis theonlymarine/land-based activitythat activelysupports the ecosystem bydrivingthe ecosystem awayfrom eutrophication thus supportingbiodiversity and sustainability andkeepingthe ecosystem functioning andprovidingthebenefits and services thatitprovides. This is doneby removalof nutrients (Nitrogen,Phosphorus and Carbon)from theecosystem bywayoffeeding on phytoplankton(topdown control),harvesting of stock andincreased nitrogen removal as N2gasthroughbenthic-pelagiccoupling(enhanced bacterialdenitrification)insediments belowshellfish.Shellfishfarmers do notgetpaidforthis valuable ecosystem servicee.g. nutrient removal whichis valuedat30.93Euro/kgfor Nitrogen and93.63euro/kgfor phosphorus (Hernandez-Sancho et al.(2010))as statedin ValuingIreland Blue Ecosystem Services publishedbySEMRU authorNorton,Detal2018. The biologicaland economic costofavoidingecosystem collapse by wayof eutrophication inducedanoxia isan immenselyhigh value. Think ofthe lossofbiodiversity, tourist activity,recreational value and ecosystem services thatawidespread anoxiceventcausedbyeutrophicationcould cause in a bay.

Shellfish aquaculture also enhances water quality also throughfiltrationofparticulates from the watercolumn thusincreasingtransmissionoflightthroughthewater column,removalof bacteria andvirusesthroughfilter feeding. Structuresusedin oyster farming enhance biodiversity(provision ofshelter and substrate)and allow forevenmore filter feeders to be presentinthe ecosystem which enhancesnutrient removal andprovides afoodsourceforother marine life. Some importantbird species e.g. BrentGeese benefitfrom oyster farmingby feeding onmacroalgaegrowing on the topofoyster bags. Otherbird species e.g.oystercatcher feedon theoysters directly. Itprovidesvaluablejobsto coastalcommunities andhas the potentialto supportregional andlocalmaritime festivals andfoodtrails.

Thus, shellfish aquacultureis amarine activitythatfitsvery comfortablyinto thethree

HarnessingOur Ocean Wealth(HOOW)Goals perfectly:

Goal1 aThrivingMarine Economy,

Goal2HealthyEcosystemsand

Goal3Strengthening engagement withthesea

Shellfishfarmsthrive in environments withGoodEnvironmentalStatus (GES)butunder the currentWater FrameworkDirectivemonitoringprogrammethereis scope foraddingimportant parameters(EnvironmentalQualityStandards EQS)for testingto giveabetterpictureofthe statusofthe environmentandbetterprotection to the shellfishindustry whichdepends wholly on goodwaterquality. Itisdisappointingto see thatonly30%oftransitional water bodies (wherealotof shellfishproductionoccurs)are in good/high statusandtheremaybe aneedfor the Water FrameworkDirectiveto focus abitmoreon theseareaswhich after allare areas whereeconomic,social, aesthetic,ecosystem servicesand natural capitalare higher thanmany other partsofthe catchment.

KindRegards,

ItaHarty

From: Cornelia Wahli

Sent: Wednesday 5 August 2020 12:21

To: rbmp

Subject: Private Cornelia Wahli

Aachments: C Wahli - Water - Public Consultatribuf

Dear Sir / Madam,

Please find enclosed my 5 point contribution for above.

I would also like to know -who monitors water quality and polluters?

Kind regards, Cornelia Wahli

Public Consultation Participation Contribution by Cornelia Wahli, 5.8.2020 in relation to Significant Water Management Issues in Ireland Public Consultation Document (2022-2027) Prepared by the Department of Housing, Planning and Local Government housing.gov.ie

For the Protection of Surface and Ground Water

and

For the Improvement of Bathing Water, Drinking Water, Shellfish Water and Aquatic Fauna and Flora Habitat

the following is proposed:

1. Pesticides, Herbicides and Fungicides Ban: any small and large scale application of such products in/on:

.

private ornamental garden including aquatics

.

commercial/professional ornamental garden both large and small scale including aquatics

.

private food production including aquatics

.

commercial/professional food production both large and small scale including aquatics

.

private animal husbandry including aquatics

.

commercial/professional animal husbandry both large and small scale including aquatics

.

private roadways

.

public roadways

2. Fertilizers Ban: any large scale application of such products in/on (except natural, biodegradable, non-run.off products such as compost, mulch etc.)

.

private ornamental garden including aquatics

.

commercial/professional ornamental garden both large and small scale including aquatics

.

private food production including aquatics

.

commercial/professional food production both large and small scale including aquatics

.

private animal husbandry including aquatics

.

commercial/professional animal husbandry both large and small scale including aquatics

.

private roadways

.

public roadways

3. Monoculture Ban

.

Monoculture systems applied in private gardens/properties/forestry/aquatics etc which are harmful to water in general but also to a diverse ecosystem and biodiversity and which contribute to climate change and climate change challenges.

.

Monoculture systems applied in commercial/professional gardens/properties/forestry/fish farms/ aquatics etc which are harmful to water in general but also to a diverse ecosystem and biodiversity and which contribute to climate change and climate change challenges.

.

Monoculture to be replaced with polyculture.

4.

Wide Scale information and education on the three points mentioned above

5.

Wide Scale information and education on life-style choices, their impacts and alternative options

From: Bernadee Connolly

Sent: Friday 7 August 2020 13:03

To: rbmp

Subject: Cork Environmental Forum CEF

Aachments: CEF Submission to the SWMI.docx

Dear Sir/ Madam,

Please find aached our submission to the Significant Water Management Issues. We thank you for the opportunity to comment on this dra. Yours sincerely, Bernie Connolly Development Coordinator

Workdays -Monday, Wednesday & Thursday

7th August 2020

Response to the Public Consultation on the Significant Water Management Issues

Bernadette Connolly Development Coordinator Cork Environmental Forum

Company No: 340723 CHY: 16288 Directors: Derry O’Farrell, James O’Donovan, Victor Branagan, Allin Gray, Catriona Courtney

Introduction

Cork Environmental Forum (CEF) was established as a non-profit organisation in 1995, inspired by the Earth Summit of 1992 in Rio de Janeiro. We believe that a sustainable world will be one which prioritises and protects environmental quality, habitats and biodiversity, where consumption and economics take cognisance of the limitations of our one planet and where there is a fairer and more equitable share of the earth’s resources.

We are involved in stimulating and sustaining active environmental awareness, concern, care and activity among sectoral interests and individuals in Cork (City & County) and beyond the region.

We work from a collaborative approach with many organisations and in relation to water issues are an active member of the Sustainable Water Network (SWAN), act as regional coordinator for the Coastwatch survey in County Cork and contribute to the National Water Forum stakeholder group.

Summary Response

Cork Environmental Forum welcomes the opportunity to submit our comments with regard to the Significant Water Management Issues.

As a long-term member of SWAN and having attended the SWMI Workshop with the Department in March and the SWAN-IEN webinar in July we fully endorse the more comprehensive submission by SWAN on behalf of all its members.

However, we wish to reiterate a few of the key points, expand on some and include some additional considerations such as Management itself and the need to broaden national measurements from solely GDP to include Well-being Indicators including social and environmental indicators that would better reflect progress on issues such as protection of our waters.

We demonstrate the efforts of one of our member’s long-term engagement in the protection of water quality in rivers and the RBMP, and how the issues on his local river reflect the countrywide reality of the impact of ongoing poor water governance.

Reiteration of Key Points

1.

Consideration of Submissions -it is impossible to evaluate the influence and consideration our submissions make, as referenced SWAN has made 18 formal submissions relating to the WFD. CEF has been engaged in the process since the onset and have made a significant number of submissions, however, we do not see how our inputs are reflected or valued. We would welcome a more transparent and meaningful inclusion of our time and efforts.

2.

Data and Information Gaps -we are being asked to submit to a process for which we lack crucial data, the actions and impacts of the 2nd RBMP have not been evaluated fully to date to better inform this consultation on the SWMIs.

3.

Systemic Failure -Ireland is about to prepare its 3rd RBMP, aside from a few recent positive steps in the right direction, including the work of the EPA on the characterization of water bodies and the establishment of LAWPRO and the NWF, we have had a systemic failure by Departments and agencies of the state and the political system to protect our waters despite the legal requirement under the WFD.

4.

Prioritisation – this is not so much a SWMI as an overall strategy, we wish to emphasise that this methodology is flawed as it only focuses on a fraction of our waterbodies. All of our water bodies are required to be in good ecological status by 2027.

5.

Time-line -we have a very short window of 6 years under the 3rd RBMP this requires radical transformative efforts in protecting our waters to deliver on the WFD requirements.

6.

Policy coherence – this is a key enabler for delivery of positive results and will achieve co-benefits for climate and biodiversity. This requires cross-departmental and whole of Government leadership not just one Department.

In our last submission in 2015 we highlighted the contradiction then of the suite of Governmental Strategic Documents including Food Wise 2025, the Forestry Programme, Marine Harvest 2020, and the Sustainable Aquaculture Programme which were “proposing to solve our water quality, ecosystem health, biodiversity loss, antibiotic resistance, and climate change problems by aggressively increasing the causes of these problems.”. If we do not address the inconsistencies and contradictory strategies across sectors then we are just wasting time, resources and on a misguided pathway that doing the same thing is going to result in a different outcome.

Expanded Notes on some of the SWMIs

i. Land Use Planning We note little reference to the National Planning Framework, Regional Spatial and Economic Strategies and the Local Authority Development Plans (out for initial consultation currently). All of these plans predict high levels of population growth which will be an added pressure and makes land-use and planning a key consideration with regard to water quality. The following is an extract from the CEF submission to the Cork County Development Plan in July in respect of protection of water:

“There are some acute issues in some areas with regard to provision of services such as water, both potable water and waste water treatment. Creating an unsustainable practice of water being tankered from one area to another and where waste from East Cork is transported to North Cork for disposal.

No additional housing or planning should get approval in the following circumstances:

.

Where capacity issues exist in the supply of essential services such as water and in the treatment of waste water.

.

On flood plains (coastal and terrestrial) – the OPW CFRAMS maps are available to show the potential for flooding.

.

In Natura designated areas and areas adjacent where building will impact on the protection status.”

Landfills

Location of landfills, many now no longer active, are a legacy of land-use planning. There is a growing issue of sites being exposed on coastal areas, waste material being washed out to sea, as well as a risk of leachate to water sources near rivers which should be a consideration.

We note within the SWMI consultations document the plans to amend legislation, training for planning authorities and decision making support tools. Whilst late in the day it is welcome to see these plans and we would like to see time-lines on these. Local Authority Managers need to be champions of water quality within their areas of remit and the planned training should be mandatory for all elected representatives including local Councillors.

ii. Management/ Water Governance

After so many years good management or good water governance should have resulted in good ecological status of our water. Management of our waters is spread across so many agencies and bodies at all levels that no one is actually held responsible for deterioration of our water quality. There are little or no consequences to any individual, agency or department for impacts, for lack of action, late delivery and there is always some excuse, mostly resources, notwithstanding that this is a factor the level of action and ambition to date is unacceptable.

There is a consequence which is a fine from Europe that the citizens will pay for.

We need systemic change and policy coherence if we are to successfully address the issues that are impacting on our water quality. We know what they are and sadly we also know the solutions but as a countryhave not been prepared to date to address the pressures on water as they conflict with current land-use and economically driven policies as already referenced above.

The Programme for Government gives a commitment to implementation of the Water Framework Directive and there is also the commitment for 25% organic farming. There is hope for some positive changes with the new CAP/ Farm to Fork Strategy and the Biodiversity Strategy. However, with report after report showing continuing declines there needs to be a much more robust, transparent and accountable system of water governance applied.

The SWMIs impact locally and solutions need to be implemented locally, however, there is a sense of abdication of responsibility for non-prioritised waterbodies within local authorities and other agencies with the responsibility perceived to rest with LAWPRO and Irish Water.

CEF has no idea what the regional committees are doing, in fact there are a host of different “expert” groups referenced in the consultation document and in the interests of the public and public participation at a minimum all minutes of all meetings and a list of representatives on each committee should be publically available and easily accessible.

iii. Public Participation

There has been a failure to communicate and raise awareness of water issues in the public arena. After the fiasco of the attempt to introduce water charges, which was regrettable as CEF agrees with charging for this vital resource, there has been a retreat from any form of a national communication strategy with regard to water. Irish Water did produce a recent documentary on the issue that helped raise some awareness.

The notion of public participation seems to present an ongoing challenge to statutory bodies.

Seen as a necessity to adhere to legislation rather than an opportunity for real collaboration. The public are invited, from time to time, at the behest of the state agencies, to inputinto a consultation such as this, to give validity to work of agencies and participate in soft measures like information days, educational events etc. However, when the public do engage by reporting pollution and other issues negatively impacting our waters the manner in which such issues are dealt with and responses received leave an impression that far from being valued for caring about water quality and trying to contribute to protecting it that such reports are a cause of extra work. It often requires multiple follow-up contacts from the person reporting the issue (on a voluntary basis – see below demonstrable case) rather than timely and active communication from the person employed to address the issue.

We demonstrate this by one of our members and the most amazing aspect is that his commitment to try to help the ecology of his river provides insurmountable motivation despite so many setbacks and being fully aware of the flaws throughout the system that augurs against improvements in water quality and a failure to respond and deliver on the RBMP.

It is not that people do not wish to engage it is the inequitable manner of engagement. There are power and resource imbalances and an inherent bias in favour of the “expert” which ignores or lacks full appreciation of the local knowledge and commitment. A more blended approach that appreciates the very necessary scientific and expert knowledge with the in-depth local familiarity and awareness of how the catchment works.

It is an opportune time right now to capture the renewed engagement of the public with their local water sources during lock-down through recreation and as a source of solace.. This could be deepened and developed through a more collaborative public participation strategy. The benefits to our physical and mental health of activities in and near water are well documented and people have really experienced this first hand in the past few months.

Citizen science is increasingly popular and a great means of engaging people meaningfully in becoming more aware of their local water body, we see this through the Coastwatch Autumn Survey. We are disappointed, despite highlighting on a number of occasions the need for a similar “Riverwatch”, that this has not been developed to date, this could be complemented with training provided from the very useful Streamscapes programme.

This would be a great way to engage people and as we see with Coastwatch once people are hooked they remain committed to surveying and keeping an eye on their shore on an ongoing basis. There is the added benefit of ongoing learning and growing awareness e.g. you don’t just want to record brown or red seaweed you want to know the name of the seaweeds you see, this goes for all aspects of nature.

As mentioned under Management/ Water Governance there are a lot of expert groups and varying levels of water governance but where is the possibility for public access, are NGOs and the public participating in these structures and even then whom and how are they selected?

iv. Coastal andTransitionalWaters

Coastal and Transitional issues have to be included as a SWMI, with over 7,000km of coastline these are really vital water bodies and we know that the status of our transitional waters and estuaries are in decline. We see very little action and work being done to date on this area.

Just this week we saw the closure of four beaches in Co. Clare due to unsafe levels of E-coli suspected from agricultural run off in the catchment and the need for further investment in Waste Water Facilities. This is yet another example of the failure of the department to manage Ireland's waters.

Ireland seems set to not only fail to meet the 10% target for Marine Protected Areas by the end of 2020 but is set on a trajectory to fail to deliver on any of the four goals with a timeline of 2020 under SDG14.

Marine Protected Areas can provide a framework to underpin active involvement by the community in the management of valued marine, coastal and island seascapes and the natural habitats, flora and fauna and the culturalheritage that they contain. Marine Protected Areas have the potential to deliver exponential social, economic and environmental benefits and help address the existential crises of our times.

The impacts of shipping and port operations, including dredging, need to be addressed within this section in addition to the other aspects referenced in the SWAN submission.

Citizen opinions, from threats, or frequency of pollution incidents to what is special about their shores which is included in the Coastwatch Autumn Survey ‘what is special about my survey unit’ is useful information that can also flag public reaction to near shore development like wind turbines and should be captured.

There is an urgent need for Ireland to transpose some of the Conventions such as the Landscape Convention, that includes Seascapes, into the regulatory framework.

Other

Wellbeing Indicators

The last decade has seen major advances in the measurement of wellbeing in national statistics often involving extensive public consultation processes. Incorporating these metrics and frameworks into policy decision-making has often involved the passing of new wellbeing legislation. Most countries are also working to align their wellbeing statistics with the United Nations Sustainable Development Goals (SDGs). Many countries have already put in place frameworks to incorporate such measurements as well as tools such as dashboards to show real time progress. We advocate for such an approach in Ireland and reflection of progress under the WFD and SDG 14 and SDG 6 could be incorporated.

The CSO has been working on expanding its work in this area in recent years and has provided a number of key reports including its Environmental Indicators Ireland 2019 report which includes a section on water -https://www.cso.ie/en/releasesandpublications/ep/p-eii/eii19/water/.

Case Study -David Lee and the Farrahy River

DavidLeeisafoundingmemberofCorkEnvironmentalForum (CEF)withalifelongpassionforangling. It is from his angling activities that he has developed a long-term concern and care for water quality, freshwater ecology and the wider nature it supports. David has spent over 30 years on the rivers of Munster reportingissuesofenvironmental concern. He is the firstpoint of contactformanymembers of his community who report pollution issues threatening the local rivers, as they know he will report the issues to the relevant authority.

David has been very active with supporting the implementation of the Water Framework Directive, initially through representation on the Advisory Group for the South West River Basin Management Plan. He is the CEF representative on the Sustainable Water Network(SWAN) and actively engaged at a local and national level on water policy issues.

David, in conjunction with his local group, has been working, with support from LAWPRO, with local farmers to keep effluent out of the River Farrahy, his local river, a spawning stream for trout and salmonwhichhasseenahugedeteriorationinqualityoverthelastnumberofyears.Whilsttheefforts onthelowerreachesaregoingwellwithlotsmoreriparianplantingandmeasuresto protecttheriver, there are 3major issues (effectivelySWMIs for that river) upstream atthe headwaters whichhave led to a significant drop in water quality affecting the ecology, especially notable since 2015:

1.

An auto-grass race track development which involved clearing a stretch of land next to the river and from which very fine silt leaches into the river and stays in suspension on a regular basis. The site is located adjacent to an SAC.

2.

Coillte has been clear felling a mature forest, the latest felling licence in 2019 led to the development of a 2km roadway with no remediation to stop silt and nutrients entering the river.

3.

There are 7 old landfills in the area, 6 unlined and one is beginning to emit leachate to the river (see previous note on landfills).

These are impacts from poor land-use andplanningdecisions,they are issues thatlocalpeople cannot address on their own. However, when it comes to water everyone and no one is responsible. In spite of years of David reporting these issues to various state organisations and agencies and in organising meetings with relevant stakeholders, adequate action has not been taken and these issues persist, further threatening the water quality and counteracting the positive work being undertaken downstream.

This of course is far from unique and rivers continue to decline due to the many pressures of which

poor planning compounded by poor enforcement is just one.

The SWMI asks a question regarding engaging the public, whilst as outlined (Pg. 4) it is far from satisfactory, there is the issue of people such as David who are very engaged. Engaged local community members such as David need to be given the respect, support. and means of fully participating in the co-design of managing the catchment and helping to restore their local river that they care for, are deeply connected to and are often far more knowledgeable about the river system than specialists with sole decision making powers. It is crucial there is a re-balancing of expertise with local knowledge and more resources channelled to support the work of such local groups who are taking real and concrete positive action in protecting water bodies, engaging their communities and having a lasting positive impact.

Conclusion

There is a need in not just identifying the most significant water issues, we have known from the scientific evidence that agriculture is the largest pressure, but a commitment to take the decisions and steps necessary to protect all waters by changing intensive land use and intensive fishing and aquaculture. This would have the best results for water and deliver co-benefits for biodiversity, climate and peoples wellbeing.

The Supreme Court has recognised that Irish People have a right to a healthy environment, this includes our very life giving resource of water and that right is being breached.

From: Breian Carroll

Sent: Friday 7 August 2020 16:38

To: rbmp

Subject: Agricultural Consultants Associan ACA

Aachments: ACA Submission WM issues 3rd cycle RBM plan for Ireland.docx

Dear Jim,

Please find aached the ACA submission in response to your call on papers for the River Basin Management Plan for Ireland 2022 – 2027.

Please contact me if anything further is required.

Thank you, Breian

ACA and/or its employees accept no liability for any errors or omissions in the informan provided in this correspondence or for any loss or damage occasioned to any person as a result of using the informan provided. The informan contained in this email and in any aachment(s)is confidenl and is designated solely for the aenn and use of the intended recipient(s). If you are not an intended recipient of this email, you must not use, disclose, copy, distribute or retain this message or any part of it.

PublicConsultationontheSignificantWaterManagementIssuesforthethird cycleRiverBasinManagementPlanforIreland2022-2027

6th August 2020

Enquiries to be directed to Mr. Breian Carroll, General Secretary ACA

1. Background

The Agricultural Consultants Association (ACA) are the sole representative body for private agricultural consultants and advisors in Ireland. Currently the ACA have 160 member offices in Ireland which employ 270 Agricultural and Environmental graduates and professionals and a further 121 employed as administration and technical staff. 11 members are Forestry Consultants.

The latest Department of Agriculture, Food and the Marine (DAFM) statistics in 2019/2020 indicate that our members provide independent advisory support services and knowledge transfer to over 55,000 Irish farmers across a wide range of programmes and schemes. The DAFM have confirmed our current market share over a range of Agricultural Schemes is as follows:

1.

TAMS –80% of applications completed.

2.

NutrientManagementPlans andNitrates Derogation applications –76%.

3.

DAFM Knowledge Transfer Programme – 52% of groups in Ireland were facilitated by ACA members.

4.

Basic PaymentScheme applications –58%.

The majority of our members support Irish farmers with technical farm advice in all sectors across farming including dairy, beef, tillage, sheep, pigs, poultry, horticulture and the environment. Additionally, many members specialise and provide enhanced services in the areas outlined in Figure 1 below.

Figure 1: Additional extension services (outside of core farm sectoral advice) provided by ACA farm consultants/advisors

ACA members provide all of these services at no cost to the Irish Exchequer. Our colleagues in Teagasc in their Advisory Section (their Research and Education Units are not being discussed here) receive significant Irish state supports to provide the same services to Irish farmers and they also collect fees from their customers, although below market rates.

2. Structure of the Farm Advisory Service and current training model

In theperiodOctobertoDecember2019,ACAconductedacomprehensiveassessment ofthe current Farm Advisory System (FAS) in Ireland, which is a register of all farm advisors in Ireland, public and private. The following data was established as a result of this review and is shown on figure 2below:

236.4 Teagasc

(from Teagasc 2017 report)

Figure 2: Analysis of the FAS 2019 list in Ireland

Although the FAS training is in place in Ireland, it falls far short of what could be achieved through a revamped and modern training programme. The current situation is inequitable, inwhichthemajorityoftrainingfundingisgiventothepublicadvisoryservice,whichcontinue to advise only32% ofthe entire farming sector (43,000farmers out of atotal of 137,000Irish farmers).Thisanomalyneedstobecorrectedifoursectorisseriousaboutmeetinganyfuture targets in the CAP as the farm advisor is one of the key influencers in farmers’ decisions.

ACA members complete in the region of 80% of allprivate advisory work. DAFMfigures state that ACA members facilitated over 50% of the farmer groups in the Knowledge Transfer programme.The map at Annex 2 shows the number of ACA member offices in Ireland which currently is 160. There are over three times more ACA offices in Ireland today than the 49 Teagasc offices as shown in Annex 3. The structure, client base and the proportional workload of the private farm advisory service in Ireland is outlined in Annex 1, which is significantly greater than Teagasc1 .

The Private Advisory Service receives training from the DAFM through the Farm Advisory System (FAS) annually, which has amounted to one or two days on average in recent years.

Private Advisors must receive the same training supports as the public advisory service to ensure equality for all advisors and to also meet the new challenges within the sector and ensure the objectives of CAP are clearly disseminated to farmer clients. ACA estimate that over €9,000 per annum is invested in upskilling every public farm advisor (Teagasc) in Ireland.

1 Teagasc Annual report2017 –Knowledge Transfer AdvisoryActivities and Outputs 2017 –page 32

ACA contribution/recommendations

ACA welcome the opportunity to contribute to this very important consultation process. As our field of expertise is in farm and land management and related agricultural environmental matters, we are outlining below our views on this subject.

Key to achievingthe ambitious 2030 environmental targets for Ireland is the development of sustainable agricultural systems. The three key components of Sustainable Agriculture are:

1.

Commercially viability -capable of delivering a realistic income for farmers and their families. Farmers must be rewarded for their efforts to address Climate Change and protect and enhance water qualitythrough acombination of higher prices for their products and additional supports that rewards their contribution to the Public Good.

2.

Environmentalprotection – all actions undertaken on farms must contribute to environmentalprotection and enhancement in their area.

3.

Sociallybeneficial– must provide a good life/work balance, safe working environment and contribute to addressingthe issues of socialisolation for the farming community. This will help to enhance generational succession in farm businesses.

While trends over the last 30 years are worrying in terms of Water Quality, there is stilltime and anumber of ways that these trends can be reversed. We must build on the positives in agriculture to bring about improvements in water quality. Such positives include farmer’s awareness of their obligations to protect the environment in which they operate. The majority of farmers manage their farming operations in aresponsible wayto protect water quality and their local environment.

Although, Irish farmers interact with their feed and agri-merchants, co-ops and other agencies, 73% retain either a private or public farm consultant/advisor annually to provide advisory services. Immediate progress can be made in the short time to engage with clients of ACA and Teagasc with any existing and new targets for the sector. To have almost 3 out of every 4farmers engaging with either advisoryprovider is very significant positive position for Ireland and should be concentrated on immediatelyto assist in the knowledge exchange of public policy initiatives. The entire focus of water and environmental policy in relation to agriculture must include ACA and the private sector as there are 94,000 farmers in Ireland who do not avail of Teagasc services.

Key Agricultural Pressures affecting Water Quality

1.

Phosphorous loss on lands with impeded drainage and steep slopes.

2.

Nitrogen loss on free draining soils.

3.

Sedimentloss -can be associated withboundPhosphorus, thus afactor in eutrophication. Sediment can damage freshwater habitats and its sources include overland flow from pasture, farm roadways, poached and ploughed areas, forestry activities, drainage and channel maintenance, development works and bank erosion, cattle access and trampling of banks. However, it must be remembered that not all sources of sediment in waters are from agriculture.

4.

Chemical residues from herbicide use andimproper disposal of chemical containers.

Current Regulation and Supports in Agriculture

Water quality and environmental issues are not new. Agriculture is regulated and/or supported through a range of measures but we have seen adeterioration in water quality and loss of biodiversity, caused in part, by pressures from agricultural sources over the last 30 years. Over the same period, farm incomes have declined, in realterms, especially in the beef sector. The key existing regulatoryinstruments include:

.

Code of Good Agricultural Practice

.

Nitrate Regulations

.

Designation of Natura Areas, SAC’s, NHA’s etc.,

.

Planning Regulations, supported bydata from agencies such as the E.P.A.

The key existingSupportmeasures include:

.

Environmental schemes such as GLAS,

.

TAMSproviding supportfor waste storage, animal housing and handlingfacilities.

1. Needtoeliminatethe conflicts inexistingagricultural supportpolicies and programmes

The basis for current farmers support is centred on eligible land area declared on their Basic Payment Scheme (BPS) applications. As habitats and scrub areas are regarded as non.grazable areas, farmers currently receive no supports under any Department of Agriculture schemes for these areas. Farmers, in effect, are penalised where natural vegetation develops, which can have significant biodiversity and water quality protection value. Farmers as a result are forced to remove such areas to protect their payments.

2. Definitivepolicy on Nitrate Regulations

The lack of clarity on the future of the Nitrate Derogations is leading to uncertainty among farmers operating highly stocked farms. There is astrong correlation between such highly stocked farms and Nitrate loss to waterbodies. Clear direction must be given on the future of derogations and proposed regulations to be applied to reduce such nutrient losses on such farms in the future. Farmers must be allowed time to adjust their stocking rates and farming systems to comply with future regulations. The future for such intensive farm businesses remains challenging untilthis clarity is provided.

3. The role oftheadvisoryservice providers indeliveringimprovedwater quality

If Ireland is to achieve the ambitious environmental and water qualitytargets, we need to achieve mind-set and behavioural changes among farmers. The role of the advisory services in Ireland is recognised by all stakeholders as being key to achievingthis. In Ireland, the advisory services are composed of private (primarily ACA members) and public sector (Teagasc), advisors. 55,000 farmers in Ireland use private sector advisors with 43,000 engaging with public sector advisors. However, the focus in addressing water quality issues has been mostlythrough the public advisory services. Critically, as the major advisory support service providers, private sector agricultural advisors must be involved in delivery of solutions to address water qualityissues.

4. Advisory support serviceproviders mustbesupportedby,andhaveaccess to, the most relevantanduptodate researchdata on environmental andwaterprotection issues

ACA must have some formal lines of communication in assistingpublic policy through proper dissemination of publicallyfunded research and information. ManyACA members have exceptional skills and knowledge and must be part of focus groups and or committees set up by government agencies and Departments.

5. Advisory support services, bothpublicandprivate mustbe giventhe resources to delivery an effective extension service thatwillensure farmers adopt mitigation measures that willimprove water quality

Our advisory services must be fit for future purpose. The process of informing and training of all advisoryproviders must start now.

As outlined above, the current Farm Advisory System (FAS) accreditation must be replaced with a comprehensive, accredited and strategically focused Continuous Professional Development (CPD)programme for advisory staff. ACA recommend the following actions:

(a)

Immediate rollout ofCPD trainingto ACA members andtheir professional staff on sustainable farming models, with a clear focus on reducing emissions and improving water quality at individual farm level,

(b)

Ongoinglong-term CPDtraining ofACA advisors, provided on an annualbasis and supported by adedicated budget from CAPfunding.

6. Integratedapproachtoassessingfarms

ACA recommend a while farm approach/assessment must be conducted immediately to collate the required individualfarm measurements that the sector and country requires. This would entail afull audit bythe farmers existing advisor of environmental assets, soil fertility, pollution control facilities, proximityto vulnerable water /catchment areas and other measurements on all Irish farms. Such an audit would establish accurate baseline measurements at individual farm level. Data from such audits willprovide the basis for targeted recommendations for actions to be undertaken at individualfarm levelto address water quality and other environmental issues identified on these farms. The baseline survey would ensure accuracy in measuringthe effectiveness of the recommended actions in the future. This is criticalfor the country ofIrelandto complete immediately.

7. Mandatory annualCPDtrainingfor farmers

The management of farms is constantly evolving with the introduction of new technologies and management practices. Unlike other professions, farmers receive miniscule structured vocationaltrainingto effectively adopt these technologies and innovative practices on their farms.

An annual CPD programme with a clear focus on sustainable agriculture, to improve profitability, protect and enhance their local environment and achieve abetter life/work balance for farmers is urgently needed.

(a) A revised Knowledge Transfer Programme

The Knowledge Transfer programme that operated under the 2015-2019CAP reform programme proved to be highly effective in the dissemination of information to farmers and achievingbehavioural change amongprogramme participants. A revised, less bureaucratic and more practical programme would improve the effectiveness of the programme. Participants would have to adopt targeted actions, identifiedfrom baseline audits to address issues on their farms.

ACA recommends that areformed, enhanced and expanded KTin the next CAP must be an essential component in the delivery and success of knowledge exchange and such a programme, along with the ongoing one to one consultations in the delivery of farm advice, will greatly assist with sectoral objectives including water quality. The social interaction of such events and meetings should not be underestimated as a key component to assisting rural isolation and farmer health and wellbeing and exchange of farmer knowledge.

ACA recommend that such atrainingprogramme must commence immediately and in advance of the proposed new CAPin 2023. This will ensure framers understand the new challenges for their sector and what is required of them and their successors in line with EU policyfor Climate Action up to 2050.

(b) Agri-Environmental Scheme training

The current Agri-environmental scheme, GLAS, required participants to attend a one day training course to provide information and instruction on the environmental options theyhad selected to implement on their farms as part of the programme. The trainingproved to be very successful in providingparticipants with information and improvingthe quality of environmental measures delivered in the scheme. Such training, provided to scheme participants on an annual basis, for the proposed Agri Environmental scheme for 2023-2027 would further enhance the effectiveness of such a scheme. It would also provide the opportunityto focus on protection waterbodies with practicaldemonstrations on farms.

An opportunity to trialthe effectiveness of such annual training will be presented with the introduction of an interim pilot environmental scheme, proposed for 2021 and 2022.

(c) Basic Payment Scheme Support

The primary support mechanism for farm incomes in Ireland is the Basic Payment System (BPS) based on an annualdeclaration of the eligible areas farmed. 44% of this payment is made up of agreening element. To qualify for this entire payment farmers must comply with the regulations set down in the Code of Good Agricultural Practice.

From 2023, the Basic Payment system is to be replaced with anew support system called Basic Income Support System (BISS). An optional Eco Scheme element may contribute up to 30% of this proposed payment. Participation byfarmers in aone day annual CPD programme on sustainable farming must be introduced to secure this payment. This would ensure that farmers, currently not utilising advisory support services, are provided with the most up to date information on protection of water quality. Farmers alreadyparticipating in annualtrainingthrough the Knowledge Transfer Programme, environmental scheme and EIP’s would automatically qualify for this payment.

(d) European Innovation Partnership (EIP)

These programmes have proven to be highly effective model and complementaryto GLAS, the current national agri environment scheme. These programmes target specific issues in local areas/regions such as the Burren Project, BRIDEProject, Pearl Mussel and Hen Harrier. Annualtraining for participants provided through these programmes, have proven to be highly effective in achievingpositive and measurable outcomes.

(e) Future Environmental Schemes in Agriculture must be targeted and Results Based

Farmers participating in proposed Agri-Environmental schemes must be required to select environmental actions in the programme that address environmental issues identified on their farms from initial farm audits –the proposed baseline measurement assessment. The effectiveness of these actions can be measured on an annualbasis and adjusted if required following consultations with their farm advisor, to ensure the planned outcomes are achieved. Such Agri environmental schemes must build on the successes of actions undertaken in previous environmental schemes and include innovative measures that will deliver significant environmental dividends. Payments must be provided through these schemes to reward farmers for protection and enhancement of high value bio diversity areas and measures undertaken to protect water quality.

Thank you for taking the time to read the Agricultural Consultants Association submission

Annex 1

Analysis of the Private Farm Advisory Service activities in Ireland in 2018 (unless stated)

1. Total number of one to one consultations by ACA members with their clients in 2018. It includes a minimum of 3 consultations in relation to the KT programme and does not include the actual contact at the KT meetings. It includes 10,000 consultations for TAMS – initial contact, farm visits, applications for grant aid and payments.

Annex 2 – 160 ACA member offices in Ireland List of all 160 members is available on www.aca.ie

Annex 3 – Teagasc offices in Ireland (Source www.teagasc.ie)

From: Alec Rolston

Sent: Thursday 6 August 2020 13:38

To: rbmp

Cc:

Subject: An Fóram Uisce|The Water Forum

Aachments: An Fóram Uisce_SWMI Submission.pdf

A Chara,

Please find aached the submission from An Fóram Uisce|The Water Forum as a whole in regard to the Significant Water Management Issues public consulta.

An Fóram Uisce welcomes further engagement in the process for the development of the 3rd River Basin Management Plan.

I would appreciate if you would acknowledge receipt of this submission.

Thank You

Alec Rolston

pp Donal Purcell Senior Execue O.cer An Fóram Uisce

Dr Alec Rolston

Research Lead

An Fóram Uisce|The Water Forum

www.thewaterforum.ie

SUBMISSION TO THE DEPARTMENT FOR HOUSING, LOCAL GOVERNMENT AND HERITAGE

PUBLIC CONSULTATION ON THE SIGNIFICANT WATER MANAGEMENT ISSUES IN IRELAND

5 August 2020

Introduction to An Fram Uisce

An Fram Uisce |The Water Forum was established in June 2018 in accordance with the provisions of Part 5 of the Water Services Act 2017, and is the only statutory body representative of all stakeholders with an interest in the quality of Ireland’s water bodies. An Fóram Uisce consists of 26 members including representatives from a wide range of organisations with direct connections to issues relating to water quality and also public water consumers. Approximately 50 different organisations were involved in the nomination of members. Further information can be found at www.thewaterforum.ie.

Summary of Submission

1.

An Fram Uisce welcomes the opportunity to respond to the public consultation on the Significant Water Management Issues (SWMI) in Ireland.

2.

The wide scope of work undertaken by the Department to develop the SWMI public consultation document is recognised.

3.

This document represents an agreed submission of An Fram Uisce as a whole.

4.

The submission is presented in three parts:

PART ONE outlines the background information upon which this submission is based. It details an overview of implementation of Integrated Catchment Management (ICM) in the 2nd cycle RBMP, providing recommendations for the improvement of each of the core components of ICM. This review of ICM implementation has been undertaken by An Fram Uisce as a means of considering whether it is a strategic issue requiring further progress during the next cycle. A total of 18 recommendations are provided for improving ICM implementation in Ireland.

Part One also introduces a new Framework for Land and Landscape Management (FILLM)

which provides An Fóram Uisce’s position for progressing the concept of ICM in respect of the

recommendations made for improving ICM delivery. The FILLM broadens ICM to include all the components of the natural environment (air, water, ecosystems, soils, rocks, land, landscape) which are interrelated and interlinked, while retaining the catchment as the appropriate landscape unit for management. By using the FILLM as the underpinning concept for water management, it is possible to re-examine how Significant Water Management Issues can be identified and mitigated to further protect and enhance Ireland’s water resources through the river basin management planning process

PART TWO provides this re-examination through overarching comment on the Significant Water Management Issues (SWMIs) described in the SWMI public consultation document, with six components of water management addressed. Part Two also reconceptualises Ireland’s Significant Water Management Issues by introducing the sector-pressure-stressor approach as an alternative for understanding and managing Ireland’s Significant Water

Management Issues. Underpinned by the FILLM, the focus of this approach is to identify the environmental stressors which manifest through water quality and WFD status. By examining the linkages between stressors, pressures and the sectors through which they are delivered, it is possible to take an integrated, holistic approach to developing and implementing mitigation measures which can also produce co-benefits for climate change and biodiversity.

PART THREE directly responds to the SWMI questions provided in the public consultation document through the prisms of Parts One and Two. It also provides brief comment on seven components that were not included in the SWMI public consultation document but which are considered by An Fram Uisce to be of vital importance to be addressed in the 3rd RBMP to

improve the integrated management of Ireland’s waters as required under the Water

Framework Directive.

5.

An Fram Uisce considers the SWMI public consultation document questions to be overly technical, consequently creating barriers and inequity for non-expert engagement in the consultation process.

6.

A total of 82 key points are outlined in response to the questions provided in the SWMI public consultation document.

7.

By taking the approaches outlined in Parts One, Two and Three of this submission, An Fram Uisce presents its position on the future management of Ireland’s water resources both through the river basin management planning cycle, and through the interlinked legislation and policies associated with water management.

8.

Further engagement in relation to the content of this submission, the FILLM and the 3rd cycle RBMP planning process is warmly welcomed.

End

Please address any correspondence as follows:

Donal Purcell, Senior Executive Officer, An Fram Uisce, Civic Offices, Limerick Road, Nenagh, County Tipperary

Contents

EXECUTIVE SUMMARY ............................................................................................................................6 INTRODUCTION.....................................................................................................................................13 PART ONE: TOWARDS A FRAMEWORK FOR LAND AND LANDSCAPE MANAGEMENT (FILLM) ............15

1.1 An overview of implementation of Integrated Catchment Management in the 2nd cycle RBMP ..........................................................................................................................................................15

1.1.1 Public engagement...............................................................................................................16 1.1.2 Developing a shared vision ..................................................................................................17 1.1.3 Characterisation at catchment scale....................................................................................17 1.1.4 Characterisation at local scale .............................................................................................18 1.1.5 Programme of measures......................................................................................................18 1.1.6 Environmental policy and regulations .................................................................................18 1.1.7 Incentives .............................................................................................................................19 1.1.8 New/upgrading infrastructure.............................................................................................19

1.1.9Inspections and enforcement of the regulations.................................................................19

1.1.10 Recommendations .............................................................................................................19

1.2 An overview of the Framework for Land and Landscape Management (FILLM)........................21

PART TWO: OVERARCHING COMMENT ON THE SIGNIFICANT WATER MANAGEMENT ISSUES IN IRELANDPUBLIC CONSULTATION .........................................................................................................23

2.1 Overarching Components of Significant Water Management Issues.........................................23

2.1.1 Governance..........................................................................................................................23

2.1.2Public and Stakeholder Engagement and Awareness..........................................................24

2.1.3Legislation and Policy Coherence ........................................................................................25

2.1.4River Basin Management Plan Monitoring and Evaluation .................................................27

2.1.5Time Lags and Timescales for Achieving WFD Status Objectives ........................................28

2.1.6Climate Change ....................................................................................................................29

2.2 Reconceptualising Ireland’s Significant Water Management Issues from

an Integrated

Land

and Landscape Management Perspective ........................................................................................30

2.2.1Examining Sectors, Pressures and Stressors as an Alternative Approach to Addressing

Significant Water Management Issues .........................................................................................31 PART THREE: SIGNIFICANT WATER MANAGEMENT ISSUES IDENTIFIED IN THE PUBLIC CONSULTATION DOCUMENT ................................................................................................................36

3.1. Addressing the SWMIs Identified in the Public Consultation Document ..................................36

3.1.1 Prioritisation.........................................................................................................................36

3.1.2Public Participation ..............................................................................................................38

3.1.3 Land-use Planning ................................................................................................................39

3.1.4 Agriculture............................................................................................................................40

3.1.5 Climate Change ....................................................................................................................43

3.1.6 Pollution of Waters (phosphorus and nitrogen) ..................................................................43

3.1.7 Physical Changes to Surface Waters/Hydromorphology (including barriers to fish migration)......................................................................................................................................45 3.1.8 Siltation ................................................................................................................................46

3.1.9 Public Health/Drinking Water Quality .................................................................................46

3.1.10 Invasive Alien Species ........................................................................................................49

3.1.11 Hazardous Chemicals .........................................................................................................50

3.1.12 Urban Pressures.................................................................................................................51

3.1.13 Other Issues –

Aquaculture................................................................................................53

3.1.14 Other Issues –

Antimicrobial Resistance (AMR) Bacteria in WasteWater ........................54

3.2. SWMIs Not Identified in the Public Consultation Document ....................................................54 Appendix 1: Background information and justification for selection of stressors ...............................56 Sediment ...........................................................................................................................................56 Nutrients (NO3, P, NH4).....................................................................................................................57 Microbes, Bacteria, Parasites and viruses ........................................................................................58 Chemicals ..........................................................................................................................................59 Invasive Alien Species .......................................................................................................................60 Microplastics.....................................................................................................................................62 Organic Matter..................................................................................................................................63 Water Level and Flow .......................................................................................................................64 Temperature .....................................................................................................................................66

EXECUTIVE SUMMARY

This document represents an agreed submission from An Fram Uisce as a whole to the public consultation on the Significant Water Management Issues for the third cycle River Basin Management Plan (RBMP) for Ireland 2022-2027.

The submission is comprised of three parts. Part One outlines the background information upon which this submission is based. It details an overview of implementation of Integrated Catchment Management (ICM) in the 2nd cycle RBMP, providing recommendations for the improvement of each of the core components of ICM. This review of ICM implementation has been undertaken by An Fram Uisce as a means of considering whether it is a strategic issue requiring further progress during the next cycle. The review covers each of the nine components of the ICM toolkit: 1) Public engagement;

2) Developing a shared vision; 3) Characterisation at catchment scale; 4) Characterisation at local scale; 5) Programmes of measures; 6) Environmental policy and regulations; 7) Incentives; 8) New/upgrading infrastructure; and 9) Inspections.

Successful implementation of ICM is based on actions for each of these 9 components of ICM in a cohesive, interwoven manner. A total of 18 recommendations are provided for improving these nine components.

Part One also introduces a new Framework for Land and Landscape Management (FILLM) which provides An Fóram Uisce’s position for progressing the concept of ICM in respect of the recommendations made for improving ICM delivery. The FILLM broadens ICM to include all the components of the natural environment (air, water, ecosystems, soils, rocks, land, landscape) which are interrelated and interlinked, while retaining the catchment as the appropriate landscape unit for management.

By doing this, the FILLM becomes the overarching framework for environmental management as a means of connecting legislation and policies such as the Water Framework Directive, the Urban Waste Water Treatment Directive, the Habitats Directive, the Floods Directive, the Drinking Water Directive, climate change adaptation and mitigation, soil conservation, spatial planning and sustainable food and timber production. In addition, it is a means for achieving the Sustainable Development Goals for 2030.

Taking such a whole-of-system approach requires a multi-disciplinary, multi-objective and multi-stakeholder process which can link the environmental components and human activities within a catchment to optimise water quality returns while also delivering co-benefits for biodiversity and climate change.

By using the FILLM as the underpinning concept for water management, it is possible to re-examine how Significant Water Management Issues can be identified and mitigated to further protect and

enhance Ireland’s water resources through the river basin management planning process. Part Two

provides this re-examination through overarching comment on the Significant Water Management Issues (SWMIs) described in the SWMI public consultation document, with six components of water management addressed: Governance; Public and stakeholder engagement and awareness; Legislation and policy coherence; RBMP monitoring and evaluation; Time lags and timescales for achieving WFD status objective; and Climate change. Some of these components are listed as SWMIs in the public consultation document, but in this submission these are not considered to be SWMIs as they can 1) Be mechanisms through which improvements in water management governance, water quality and Water Framework Directive (WFD) status can be made, for example Prioritisation and Public Participation; or 2) Manifest other water management issues.

Part Two also reconceptualises Ireland’s Significant Water Management Issues by introducing the sector-pressure-stressor approach as an alternative for understanding and managing Ireland’s Significant Water Management Issues. Underpinned by the FILLM, the focus of this approach is to identify the environmental stressors which manifest through water quality and WFD status. By examining the linkages between stressors, pressures and the sectors through which they are delivered, it is possible to take an integrated, holistic approach to developing and implementing mitigation measures which can also produce co-benefits for climate change and biodiversity.

Following an examination of the 2nd RBMP and the SWMI public consultation document and the international literature, eight stressors are identified: sediment, nutrients (nitrogen, in terms of nitrate and ammonium, and phosphorus), microbes (bacteria, viruses and parasites), chemicals, organic matter, microplastics, water level and flow, and temperature. This list of stressors and their linked pressures and sectors may not be exhaustive, but are used to highlight that by focusing on the linkages of each of these environmental stressors with the pressures and sectors through which they are manifested, it is possible to create a more holistic picture of the complex interactions acting on

Ireland’s waters.

While Parts One and Two review ICM implementation and introduce the FILLM as a new environmental management framework, and the sector-pressure-stressor approach as an alternative for identifying and addressing SWMIs, Part Three directly responds to the SWMI questions provided in the public consultation document through the prisms of Parts One and Two. A summary of the key points addressed through answering these questions are provided below.

•

While it is recognised that limited resources must be sparingly shared, An Fram Uisce considers that the prioritisation of measures into 190 sub-catchment Priority Areas for Action (PAAs) undertaken in the 2nd RBMP contravenes Ireland’s obligations under Articles 3 and 4 of the Water Framework Directive.

•

Prioritisation of resources to PAAs can make it difficult to address water quality deterioration in non-prioritised areas.

•

Investment in protection and restoration of water quality is needed.

•

Prioritising PAAs in the 2nd RBMP failed to fully implement ICM by taking a sub-catchment approach to prioritisation.

•

There is currently a lack of quantitative evidence to support claims of improvements in water quality in PAAs as a direct result of LAWPRO and ASSAP actions.

•

Resources provided to Local Authorities to protect and improve water quality outside of PAAs are insufficient.

•

Current resources available to Local Authorities for water quality protect and improve measures outside of PAAs may be redirected to other non-water areas as a result of a perception that LAWPRO is undertaking the necessary work.

INTRODUCTION

The vision of An Fram Uisce is that Ireland has clean and healthy waters, capable of supporting biodiversity and providing the basis for a productive and healthy economic and cultural life. The Forum’s mission is to ensure that all stakeholders are regularly reminded of this vision and their role in achieving and supporting it.

This document represents the submission of An Fram Uisce to the public consultation on the Significant Water Management Issues for the third cycle River Basin Management Plan for Ireland 2022-2027.

The submission is comprised of three parts. Part One outlines the background information upon which this submission is based. It details an overview of implementation of Integrated Catchment Management (ICM) in the 2nd cycle River Basin Management Plan, providing recommendations for the improvement of each of the core components of ICM.

Part One also introduces a new Framework for Land and Landscape Management (FILLM)1 which provides An Fóram Uisce’s position for progressing the concept of ICM. The FILLM broadens ICM to include all the components of the natural environment (air, water, ecosystems, soils, rocks, land, landscape) which are interrelated and interlinked, while retaining the catchment as the appropriate landscape unit for management.

Using the FILLM as the underpinning concept, Part Two provides overarching comment on the Significant Water Management Issues (SWMIs) described in the SWMI public consultation document. Six overarching components of water management are addressed. Some of these overarching components are listed as SWMIs in the public consultation document, but in this submission these are not considered to be SWMIs as they can 1) Be mechanisms through which improvements in water management governance, water quality and Water Framework Directive (WFD) status can be made, for example Prioritisation and Public Participation; or 2) Manifest other water management issues.

Part Two reconceptualises Ireland’s Significant Water Management Issues by introducing the sector.pressure-stressor approach as an alternative for understanding and managing the SWMIs which

impact on Ireland’s aquatic environments. Underpinned by the FILLM, the focus of this approach is to

identify the environmental stressors which manifest through water quality and WFD status. By examining the linkages between stressors, pressures and the sectors through which they are delivered, it is possible to take an integrated, holistic approach to developing and implementing mitigation measures which can also produce co-benefits for climate change and biodiversity.

Part Three directly responds to the SWMI questions provided in the public consultation document through the prisms of the FILLM and the sector-pressure-stressor approach described in Parts One and Two respectively.

By taking these approaches, An Fram Uisce outlines its position on the future management of

Ireland’s water resources, both through the river basin management planning cycle, and through the

interlinked legislation and policies associated with water management. Further engagement in

1 An Fóram Uisce (2020). Protecting and enhancing our environment: A Framework for Integrated Land and Landscape Management. Available from: https://thewaterforum.ie/app/uploads/2020/07/An-Fóram-Uisce_Framework-for-Integrated.

Land-and-Landscape-Management.pdf

relation to the content of this submission, the FILLM and the 3rd cycle RBMP planning process is welcome.

PART ONE: TOWARDS A FRAMEWORK FOR LAND AND LANDSCAPE MANAGEMENT (FILLM)

1.1 An overview of implementation of Integrated Catchment Management in the 2nd cycle RBMP

The central concept to the Water Framework Directive (WFD) is integration as this is seen as key to the management and protection of water within river basin districts. This includes integration of, for instance: i) all water resources combining fresh surface water and groundwater, wetlands, coastal water resources at the catchment scale; ii) environmental objectives for water bodies; iii) water uses, functions and values; iv) disciplines and expertise; v) stakeholders and civil society; vi) measures to achieve the objectives; and vii) the different decision-making levels (local, regional and national) that influence water management. The Integrated Catchment Management (ICM) approach was developed as the means of enabling the required integration. This is acknowledged in the River Basin Management Plan (RBMP) for Ireland 2018-20212 as follows: “A new approach to implementation known as ‘integrated catchment management’ is being used to support the development and implementation of the RBMP, using the catchment (an area that contributes water to a river and its tributaries, with all water ultimately running to a single outlet) as the means to bring together all public bodies, communities and businesses.”

A review of the implementation of ICM has been undertaken by An Fram Uisce as a means of considering whether it is a strategic issue requiring further progress during the next cycle.

The ICM components or ‘toolkit’, outlined in

Table 1 is used as the basis for considering the use of ICM to-date and for making recommendations for the next RBMP in the final section.

It is recognised that a number of evaluative studies are currently underway, and these are awaited with interest. The overall sense, however, is that the public body that applies the ICM approach most consistently in its work is LAWPRO in collaboration with ASSAP farm advisors (primarily Teagasc). Specific units, e.g. EPA Catchment Science & Management Unit, and individuals in EPA and local authorities also use the approach as the basis for their work. It is considered that this uneven implementation of ICM is unsatisfactory and is hindering progress towards achieving WFD objectives.

2 https://www.housing.gov.ie/water/water-quality/river-basin-management-plans/river-basin-management-plan-2018.

2021

Table 1: The Integrated Catchment Management Toolkit3

‘Tools in the toolkit’

3. 6. 1. Public engagement 2. Developing a shared vision Characterisation at catchment scale 4. Characterisation at local scale 5. Programmes of measures Environmental Policy & Regulations 7. Incentives 8. New/upgrading infrastructure 9. Inspections

1.1.1 Public engagement

The current measures – establishment of An Fram Uisce, work of LAWPRO together with ASSAP farm advisors, communications via the website www.catchments.ie, and the input and support of the Rivers Trusts – represent significant progress on public and stakeholder engagement during the 2nd RBMP cycle.

Successful, integrated catchment management must be based on social acceptability by local communities as well as on protection and rehabilitation measures. This requires effective public engagement based on mutual respect and an understanding of community values and aspirations. It brings the social (including political), wellbeing (physical and mental), cultural and economic dimensions to catchment management. In essence, ICM requires scientists and policy makers to find ways to walk alongside the people who live and work in the catchment. An Fram Uisce believes that significant further progress is needed in this area during the next RBMP cycle as a priority and that clear proposals to enable this be included in the RBMP.

A truly collaborative approach to ICM would include stakeholders from the earliest possible stage. Local expertise must be engaged, not at some later point in the ICM process, but from the very beginning and it should be allowed meaningful impact in decision-making and actions undertaken4 . The delay in timelines on the implementation of the 2nd RBMP meant that LAWPRO Community Water Officers were appointed in late 2016 and the publication of the draft RBMP in April 2017 resulted in

3 http://lawaters.ie/technical-resources/

4Bresnihan, P and Hesse, A. (2019). Public engagement in water governance. Report to An Fóram Uisce. Available from:

https://thewaterforum.ie/app/uploads/2020/03/Water-Forum_Public-Participation_Bresnihan-and-Hesse_2019.pdf

there not being enough time for such meaningful early engagement with the public in the planning process for the 2nd cycle.

Since then however, significant progress is being made. Targeted community engagement has led to a growing number of Rivers Trusts and Catchment Associations across the country. DHLGH is currently supporting a Rivers Trusts Resilience Pilot project whereby the Inishowen and Maigue Rivers Trusts are funded to employ a project officer to deliver their objectives over the next 3 years. Rivers Trusts are community led and driven, their objectives are designed by the community and all encompass water quality, ecological integrity, biodiversity protection, addressing alien species as well as education and training programmes and most have an aspect related to local economic development and tourism.

Some communities have facilitated community development ‘visioning’ approaches to define their

objectives and action plan for their local river catchments. As these visioning workshops are open to and targeted at all members of the community, all age groups and backgrounds, a wide range of interests and perspectives are represented. This community development approach initiated and developed by the Rivers trusts in the UK has been undertaken in a number of catchments including the Nore river catchment and Dundalk Bay catchment, amongst others. Through this RIPPLE5 process the community identifies actions that they would like to see happen in their catchment, they consider how these actions might be delivered and who might take the lead in the delivery of each action, and in this way they create a plan for their catchment6. At further meetings, this plan is ratified and turned

into a ‘vision’ for their catchment. To date, these community plans, whilst pertaining to local river

catchments do not only include actions for water quality but also for biodiversity, climate, heritage, education and tourism, an outcome that might be expected when ‘all of the community’ have an input to the plan7 . The aim of promoting a ‘visioning’ exercise within a catchment is to encourage thinking and networking that might initiate the development of a catchment association or rivers trust to lead on the implementation of the community catchment plan.

1.1.2 Developing a shared vision

Developing a collective vision and strategy in a multi-stakeholder catchment situation, while challenging, is critical to establishing priorities and encouraging practice change where needed as a means of dealing successfully with certain of the environmental stressors and pressures. This is particularly important with regard to the Statutory Agencies each of whom has a particular and distinctive role but who need to work and communicate more closely with one another in formulating a joint agenda. Realising this vision requires an engagement process based on the principles such as trust, respect and open communication. The strategy must be locally meaningful as well as nested in the broader scale objectives.

1.1.3 Characterisation at catchment scale

Catchment characterisation is undertaken by the EPA Catchments Unit in collaboration with public bodies such as local authorities, IFI and Irish Water. A comprehensive integrated assessment of all

5 Ballinderry River Trust and WWF (Undated). RIPPLE: A river action plan for the Ballinderry. Available from:

http://assets.wwf.org.uk/downloads/wwf_ripple_brochure_final_layout_1.pdf

6 https://fliphtml5.com/dabkz/rmnn/basic

7 https://www.catchments.ie/creating-vision-dundalk-bay-rivers/

relevant scientific aspects of catchments and sub-catchments is undertaken. The relevance and quality of this work is acknowledged, and An Fram Uisce supports its continuation.

1.1.4 Characterisation at local scale

The application of ICM is already happening as part of the new Governance structures set up as part of the 2nd RBMP cycle. The development of these structures resulted from learnings from the first RBMP and aimed to ensure a more co-ordinated approach to the development and implementation of 2nd cycle measures, ‘the right measure in the right place’.

LAWPRO is a Local Authority shared service with responsibility for managing this ICM approach on a national basis with significant support from the EPA Catchments Unit. Five Regional Management Committees consisting of Local Authority Directors of Service with direct responsibility for staff delivering against RBMP actions, chaired by a Local Authority CEO, report back to the National Co.ordination and Management Committee. There are 5 Regional Operational committees comprising staff from all the Agencies delivering actions to address the requirements of the RBMP Priority Action Areas and this committee is supported primarily by the LAWPRO Science teams, the EPA Catchments Unit and Chaired by a Local Authority Director of Service. Both Committees meet on a regular basis to discuss progress on the implementation of the RBMP, fieldwork results and potential measures within the Priority Areas of Actions.

A key part of the deliverables in the 2nd Cycle was the appointment in late 2016 of 12 Community Water Officers whose role it is to ‘engage local communities’ in the management of their local water bodies. Supported by initiatives such as the ‘Community Water Development Fund’ they engage with

communities and support them to take actions to improve water quality, as well as raise awareness and build capacity through training programmes. An internal evaluation of LAWPRO work has recently been completed.

1.1.5 Programme of measures

Progress has been made in undertaking measures to achieve WFD objectives. However, the continuing deterioration of our water quality8 indicates that the measures being implemented are not adequate or have yet to achieve environmental outcomes. Currently there is an information deficit on progress updates through the RBMP monitoring and evaluation process (described further in Section 2.1.4), in particular in relation to the effectiveness of measures in addressing specific pressures and impacts, and due to this deficiency it is hard to be definitive on progress of RBMP measures.

1.1.6 Environmental policy and regulations

While regulations alone will not enable environmental objectives to be met, they are nevertheless a critically important ‘tool in the toolkit’. The high standard of many of the environmental regulations, such as the Good Agricultural Practices Regulations are recognised. However, they tend to be ‘one size fits all’ and a number of policy gaps are evident.

For instance, payments under the current CAP Pillar 1, farmers’ remuneration is based on land under agriculture and therefore if measures for water quality and biodiversity are implemented, such as

8 EPA (2019). Water Quality in Ireland 2013-2018. Available from:

https://www.epa.ie/pubs/reports/water/waterqua/waterqualityinireland2013-2018.html

wide riparian buffer strips, those payments are lost. In addition, certain categories of 'unworked', low productivity farmland with environmental benefits (such as scrub, woods and bare rock) are ineligible for payments leading to some farmers converting these areas to farmland so that they may be eligible for subsidies. For farmers within the 2nd RBMP Priority Areas for Action (PAAs), this issue has been addressed in that they no longer lose CAP payments for lands given over to achieving environmental benefits. There is a strong case for this measure to be made available to all farmers, not just those located within PAAs.

1.1.7 Incentives

While An Fram Uisce supports compliance with the regulations as a requirement, a policy of targeted incentives to enable land-use change, for instance, on high risk land or where large environmental benefits are feasible should be utilised as a means of achieving environmental objectives.

1.1.8 New/upgrading infrastructure

Over half of urban wastewater is not meeting EU standards9 and the Water Advisory Body has noted that Ireland is not addressing the deficiencies in its wastewater treatment at a fast-enough pace10. Expediting urban wastewater treatment infrastructure upgrades is critical to achieve RBMP objectives. Of immediate priority are the 36 towns where raw sewage is being released untreated into local receiving waters.

Obtaining progress updates on wastewater infrastructure improvements remains challenging, particularly with regards to measures identified in the 2nd RBMP. This is in part due to reporting structures and mechanisms that are not aligned to RBMP objectives and KPIs. A revision of progress reporting, monitoring and evaluation, and provision/availability of information is required for the 3rd RBMP cycle.

1.1.9 Inspections and enforcement of the regulations

Engagement and collaboration should be prioritised as the means of enabling both practice change where needed and social acceptability for environmental protection actions over compliance checking and sanctions, which can often cause alienation towards environmental protection. Nevertheless, enforcement of regulations is essential as a means of enabling compliance and indicating to those that are complying that the system is being applied in a fair manner. However, inspections are not always incorporated adequately with the other ICM ‘tools in the toolkit’ and therefore their cost-effectiveness and efficiency in achieving environmental outcomes could be improved.

1.1.10 Recommendations

Successful implementation of ICM is based on actions for each of the components in a cohesive, interwoven manner. Recommendations for the components listed in Table 1 are outlined below.

ICM Component Recommendations

Public engagement 1. That local communities and individuals be involved in social learning and decision-making by means of implementation of a participatory process at catchment and/or sub-catchment level in all catchments, i.e. not only those with an ‘improvement’ objective, but also those with a ‘protection’

9EPA (2019). Urban Waste Water Treatment in 2018. Available from: https://www.epa.ie/water/uww/wwater/

10 Water Advisory Body (2019). Quarterly Report No.1 October 2019. Available from:

https://wateradvisorybody.ie/quarterly-reports/

objective. Account should be taken of the An Fram Uisce Briefing Note on public engagement and the experience and expertise of LAWPRO and the River Trusts. 2. As farm advisors are at the forefront of liaising with farmers and the public on environmental issues arising from farming, relevant training on environmental aspects such as water quality and ecology, climate change and biodiversity should be part of undergraduate agriculture courses and ongoing education. All agricultural trainers and educators should themselves be trained in the best practices of water quality, climate change and biodiversity protection.

Developing a 3. That developing a shared vision be a component of the public

shared vision engagement. 4. That a shared vision (including of the role and importance of the ICM approach) is developed among all the relevant public body stakeholders, such as NPWS, OPW, IFI, local authority Environment and Planning Sections, LAWPRO, Irish Water and EPA, within the existing governance and co-ordination structures.

Characterisation at catchment scale 5. That the multidisciplinary approach and collaboration with relevant public bodies continue.

Characterisation at 6. That the approach used by LAWPRO should be applied in all remaining

local scale catchments and sub-catchments during the next cycle, including not only the Areas for Improvement in Priority Areas for Action (PAAs) as currently, but also the Areas for Protection. 7. That training of local authority staff on local scale characterisation be initiated as a means of following the ‘right measure in the right place’ philosophy in dealing with diffuse and small point sources. 8. That greater input from communities in catchments be facilitated. 9. That consideration be given to dealing with whole catchment areas in an integrated manner rather than the current practice of dealing with sub-catchments in PAAs.

Programmes of 10. Greater transparency in the monitoring and evaluation of principal

measures actions identified in the RBMP and, the publication of interim reports would achieve greater transparency and assist in the evaluation of progress. 11. More ambitious programmes in wastewater treatment and leakage and mains replacement should be undertaken.

Environmental 12. That a review of possible policy/regulatory gaps be undertaken.

policy & 13. That the ‘area for eligibility’ under Pillar 1 of CAP be modified to take

Regulations account of Pillar 2 requirements and be applied countrywide, rather than just in PAAs as is the situation currently.

14. That the development and implementation of County Development Plans (CDP) and Local Economic and Community Plans (LECP) for each local authority area build upon local community catchment and neighbourhood planning processes using a collaborative, consultative and participative approach in doing so.

Incentives 15. That, with regard to payments to farmers, while Pillar 2 payments (or whatever equivalent payments in the new CAP are called) incentivise environmental protection, consideration should be given to the means of making additional resources available. 16. That consideration be given to ‘public money for public goods’ as a principle and to utilising ‘results-based payments’ as a means of achieving environmental outcomes.

New/upgrading infrastructure 17. That a review of the adequacy of slurry storage be undertaken and, if considered necessary, grant aid is provided for increasing storage facilities.

Inspections 18. Where this is not already the situation, the approach to inspections should, in so far as is practicable, not be ‘stand-alone’ but should be part of an ICM process and should be based on and take account of the characterisation results.

1.2 An overview of the Framework for Land and Landscape Management (FILLM)

In the context of Section 1.1, above, a position paper is presented by An Fram Uisce, available here, which outlines a Framework for Land and Landscape Management (FILLM).

The FILLM builds on the ICM approach detailed in Section 1.1. and broadens it to include all the components of the natural environment (air, water, ecosystems, soils, rocks, land, landscape) which are interrelated and interlinked, while retaining the catchment as the appropriate landscape unit for management. By doing this, the FILLM becomes the overarching framework for environmental management as a means of connecting legislation and policies such as the Water Framework Directive, the Urban Waste Water Treatment Directive, the Habitats Directive, the Floods Directive, the Drinking Water Directive, climate change adaptation and mitigation, soil conservation, spatial planning and sustainable food and timber production. In addition, it is a means of achieving the UN Sustainable Development Goals (SDGs) for 2030.

Taking such a whole-of-system approach requires a multi-disciplinary, multi-objective and multi-stakeholder approach which can link the environmental components and human activities within a catchment to optimise water quality returns while also delivering co-benefits for biodiversity and climate change.

By using the FILLM as the underpinning concept for water management, it is possible to re-examine how Significant Water Management Issues can be identified and mitigated to further protect and enhance Ireland’s water resources through the river basin management planning process.

Part Two of this submission provides this re-examination of SWMIs, firstly through an overarching comment on the Significant Water Management Issues as presented in the SWMI public consultation document; and secondly by outlining the sector-pressure-stressor approach as an alternative for identifying and managing Ireland’s SWMIs.

PART TWO: OVERARCHING COMMENT ON THE SIGNIFICANT

WATER MANAGEMENT ISSUES IN IRELAND

PUBLIC CONSULTATION

2.1 Overarching Components of Significant Water Management Issues

The SWMI public consultation document identifies 12 Significant Water Management Issues and two ‘other Issues’ which are impacting on Ireland’s water environment. It is considered that, rather than being specific SWMIs, some of these identified issues are higher level, overarching components of water management which can:

1.

Be mechanisms through which improvements in water management governance, water quality and WFD status can be made, for example Prioritisation and Public Participation. Or

2.

Manifest other water management issues. For example, climate change is a direct driver11 of changes in ecosystems, for instance with regards to water availability, water quality and biodiversity.

Below, An Fram outlines six of these overarching components and details rationale surrounding aspects of each that can be improved for the 3rd river basin management planning cycle.

2.1.1 Governance

The revisions to the broader governance structure implemented in the 2nd RBMP were welcome and it is recognised that they represent improvements on the previous governance structures for water management in Ireland.

Many difficulties that present themselves in the management of water can be a result, solely or in part, of water governance structures and differences in perceptions as to what ‘governance’ means. “For some, governance is an instrument, a means to achieve certain ends, an administrative and

technical toolkit that can be used in different contexts to reach a given objective, such as enforcing a particular water policy. For others, governance is a process involving not the implementation of decisions taken by experts and powerholders, but rather the debate of alternative, often rival projects of societal development, and the definition of the ends and means that must be pursued by society, through a process of substantive democratic participation”12.

It is considered that many perceptions of governance focus primarily on governance as a process to implement decision by experts and powerholders. Recognising that governance can also be implemented through improved public and stakeholder participation is essential for participative water governance in Ireland and this topic is the subject of a briefing note detailed further in Section

2.1.2 of this submission.

11 A driver is any natural or human-induced factor that directly or indirectly causes a change in an ecosystem. A direct driver unequivocally influences ecosystem processes. An indirect driver operates more diffusely by altering one or more direct drivers. Climate variability and change has been identified as a direct driver of ecosystem change. Millennium Ecosystem Assessment (2005). Scenarios Assessment. Chapter 7: Drivers of change in ecosystem condition and services.

https://www.millenniumassessment.org/documents/document.331.aspx.pdf

12 Castro, J.E. (2007). Water governance in the 21st Century. Ambiente and Sociedade 10. http://dx.doi.org/10.1590/S1414.

753X2007000200007.

The following aspects of Ireland’s governance in water management can be improved:

•

Transparency of each of the relevant bodies within the RBMP governance structure in terms of

o

Publication of meeting minutes

o

Visibility of membership of all bodies

o

Visibility of reporting by all bodies

o

Provision of information as requested

o

Linkages and communication between relevant bodies for shared and collaborative approaches to water management

o

Visibility and publication of progress towards achieving RBMP targets, goals and KPIs (see Section 2.1.4 for further information on monitoring and evaluation)

•

Recognition that the focus of water governance is not solely to implement decision-making processes undertaken by experts and powerholders.

•

Incorporating public and stakeholder engagement through the core principles of engagement as outlined in Section 2.1.2.

Participation in the recently initiated IPA-EPA research programme on Experimental Governance and the receipt the project recommendations is welcomed. Clear and transparent processes as to how any recommendations provided by the research project can be incorporated into the 3rd RBMP cycle should be clearly communicated, particularly as the results and recommendations from the research project may not be available until after implementation of the 3rd cycle RBMP has begun.

2.1.2 Public and Stakeholder Engagement and Awareness

Public and stakeholder engagement is critical for the successful management of Irelands water resources through the river basin management planning process, and public engagement is a legal requirement of the Water Framework Directive and is included in the Dublin Principles (1992)13 and as a core component of the Aarhus convention14. Stakeholder engagement is a principle of good water governance, incentivised in a broader context of a bottom-up call for open government and society15.

It is recognised that improvements in public and stakeholder engagement have been introduced through the governance structures as part of the 2nd RBMP, including the establishment of An Fram Uisce itself as well as the Local Authority Waters Programme (LAWPRO) and the Agricultural Sustainability Support Programme (ASSAP).

There is concern regarding the monitoring and evaluation processes undertaken on engagement actions being delivered as part of the second river basin management planning cycle. This issue is addressed under Section 2.1.4 of this response. In addition, there has been a distinct lack of both qualitative and quantitative assessments of changes in public awareness of water management issues as a result of the structures established in the 2nd RBMP. Such assessments are necessary to inform the success or otherwise of these structures and to inform improvements in engagement practices into the future.

13 The Dublin Statement on Water and Sustainable Development. http://www.un-documents.net/h2o-dub.htm

14 Convention on Access to Information, Public Participation in Decision-Making and Access to Justice in Environmental Matters. https://ec.europa.eu/environment/aarhus/

15 International Network of Basin Organisations (INBO) (2014). Stakeholder engagement for inclusive water governance. INBO, Paris.

In early 2020, An Fram Uisce issued a briefing note on Public Engagement in Managing Ireland’s Waters to the then DHPLG. The note made four high level recommendations for the improvement of public engagement processes:

1. Introduce and support public participation processes which incorporate the three key principles of effective public engagement:

. address inequity and power imbalances between different individuals and stakeholder groups . incorporate various forms of knowledge/expertise to recognise the value of lay knowledge as well as scientific expertise . address issues of scale e.g. how pressures and processes that operate at national levels circumscribe local decision-making regarding water management.

2.

Conduct an evaluation of current engagement initiatives based on the above principles. This should also include an assessment of wider water governance for compliance with good governance principles: accountability, transparency, equity, inclusiveness, responsiveness, effectiveness, and efficiency. This is because such governance is necessary to support public engagement16.

3.

Include communities and individuals in procedures and decision-making around water resources from the beginning. This recognises the value of their knowledge early in the catchment management process. It also elicits concerns, connections, and expertise early on and, vitally, it builds trust.

4.

Support medium/long-term interdisciplinary research on public engagement including in the form of pilot projects. These should trial a range of approaches, while integrating multiple forms of expertise (e.g. biological; sociological; lay) into scientific research in ways that produce meaningful public engagement. Because this kind of participatory research involves time to establish relations of trust between stakeholders and across disciplines and expertise, medium/long-term institutional and financial supports are essential.

In particular, strong improvements can be made regarding the monitoring, evaluation, review and implementation of engagement practices to learn lessons of what works well and what can be improved to inform future actions.

In developing the FILLM approach, An Fram Uisce was particularly concerned to ensure that public engagement should be a requirement at all stages, and this has been included in the approach.

2.1.3 Legislation and Policy Coherence

As the overarching national management plan associated with water management in Ireland, the River Basin Management Plan is inherently linked with multiple EU legislation and national policies. These linkages are all the more explicit when examined within the FILLM. The SWMI public consultation document references the linkages with other EU Directives and the importance of consistent policy integration, tying the third cycle RBMP to Climate Adaptation Plans, Marine Spatial Planning, Flood

16 An Fóram recognises and welcomes the newly initiated IPA_EPA research project on Experimental Governance which has the potential to review and address deficiencies in the current governance structures.

Risk Management Plans, and Biodiversity Action Plans, for example (SWMI public consultation document, p. 7).

An Fram welcomes the recognition of these interlinkages between RBMP actions and other legislation, policy and plans. In the development of the actions for the 3rd RBMP following the closing of the SWMI public consultation period and the collation and responses to submissions, it is proposed that that the linkages for each action to achieving initiatives in other relevant plans and policy are explicitly stated.

It is also proposed that explicit linkages are made between the actions of the 3rd RBMP and achieving the UN Sustainable Development Goals17 in Ireland. Research being undertaken by University of College Cork18 is focussing on SDG17: Partnerships for the Goals, and in particular Target 17.4 Enhance policy coherence for sustainable development. The research identifies the linkages between the RBMP and other policies towards achieving the SDGs and the 3rd RBMP should expand on these.

Ireland is lagging behind other countries in its integration of the SDGs into water-related management planning and implementation. For example, Sweden has incorporated the SDGs and the 2030 Agenda into governance and decision-making processes and measures, and the SDGs are reflected in the activities of all government ministries. A summary as to how Sweden plans to achieve SDG6 Clean Water and Sanitation highlights that good governance lies at the heart of implementation19.

In 2019, then Minister for Communications, Climate Action and Environment, Richard Bruton, appointed 12 leaders to drive forward Ireland’s progress towards the SDGs. Water underpins all of the SDGs, yet there is no designated champion for delivering water-related actions to achieve the SDGs. Given its statutory role in water management, it is proposed that An Fram Uisce is appointed as a champion body for the delivery of the SDGs and their water-related actions.

As well as the RBMP examining its synergies with other policies and plans, it is equally essential that those policies and plans recognise the importance of their linkages with the RBMP. In its submissions under the DHPLG public consultations on the Marine Strategy Framework Directive and the National Marine Planning Framework, An Fram Uisce expressed its concern that responsibility for implementing actions relating to the near shore environment may simply be deferred to another legislative process (e.g. the WFD and RBMP for transitional waters) without overarching governance to undertake an integrated approach to managing Ireland’s river catchments, transitional waters and coastal waters. Simply deferring responsibility to another legislative process reinforces governance silos, limits mitigating actions and restricts the integrated and collaborative approach needed to address the environmental status of Ireland’s near shore environment. The SWMI public consultation document minimally identifies the linkages between the identified SWMIs and near coastal and transitional water issues despite the latter being core components of RBMPs to achieve the WFD.

DHLGH is strongly encouraged to ensure that robust policy coherence, transparency of action and integrated and collaborative governance and management is implemented in the 3rd cycle RBMP.

17 https://www.un.org/sustainabledevelopment/

18 Identifying Interactions for SDG Implementation in Ireland: SDG4I. www.sdg4i.ie

19 https://www.government.se/49f47b/contentassets/3bef47b49ed64a75bcdf56ff053ccaea/6---clean-water-and.

sanitation.pdf

2.1.4 River Basin Management Plan Monitoring and Evaluation

Monitoring and evaluation is an essential component of an adaptive management process which facilitates learning from previous actions to deliver improved actions in the future. There are several types of monitoring and evaluation, including:

•

Process monitoring, where data is collected and analysed to establish whether actions are being delivered as required to achieve the intended results.

•

Financial monitoring, where program expenditure is monitored to ensure adherence to financial budgets.

•

Impact monitoring, which assesses whether an action is achieving the desired impact or benefits.

For successful monitoring and evaluation, the data collected must be analysed against a set of predetermined indicators, for example Key Performance Indicators (KPIs), against which progress can be tracked.

The 2nd RBMP states that (2nd RBMP, p.126):

•

Responsibility for monitoring and evaluation of the RBMP is the responsibility of the National Technical Implementation Group (NTIG, with support of the regional structures).

•

Oversight of national implementation measures given by the National Coordination Management Committee (NCMC).

•

Regional Integrated Catchment Management Programmes will set out details of planned interventions which can be monitored over time.

•

The implementation of measures in the regional work programmes must be continuously monitored and evaluated.

•

Each regional committee will, therefore, produce a concise annual report that will provide an update on implementation progress and evaluation of measures implemented.

•

This reporting will be integrated with the WFD web-based application insofar as possible (accessible only to EPA staff, and other public agencies and local authorities engaged in WFD-work).

•

The website www.catchments.ie will be a valuable source of up-to-date river basin management plan information for the general public.

In addition, with regards to monitoring progress for ‘Further Assessment of Areas’,the 2nd RBMP states that “suitable performance indicators for tracking progress will be designed. The Key performance Indicators (KPIs) will be monitored and used to track progress” (2nd RBMP, p.122).

It is considered that the monitoring and evaluation undertaken for the 2nd RBMP must be improved for the 3rd RBMP cycle regarding:

1.

Unclear monitoring and evaluation processes being undertaken

2.

Transparency and availability of KPIs against which performance can be tracked.

3.

Availability of data against which progress of the 2nd RBMP can be tracked.

4.

Transparency and availability of monitoring and evaluation actions undertaken by each body within the revised 2nd RBMP governance structure.

5.

Transparency and availability of the annual reports produced by each regional committee showing progress on implementation and evaluation of measures.

6.

A lack of a coherent ‘mid-term review’ process of the 2nd RBMP to inform progress, adapt measures if necessary, and inform the 3rd RBMP cycle.

7.

A clear and transparent process of how the monitoring and evaluation evidence generated during the 2nd RBMP timeframe is used to inform the identification of SWMIs for public consultation and to inform the 3rd RBMP planning cycle.

The recent review of LAWPRO, and the EPA-IPA research project on Experimental Governance that will review the governance processes introduced in the 2nd RBMP are both welcomed. An Fram Uisce will be undertaking a review of its own process later in 2020 to identify avenues for improving its own functioning, both internal and external to the Forum.

In providing these recommendations on monitoring and evaluation, it is recognised that for certain aspects of 2nd cycle RBMP implementation, time delays are apparent as to when improvements in status or results of measures may be observed. Further details on these time lags and timescales for achieving WFD Status Objectives are provided in Section 2.1.5.

2.1.5 Time Lags and Timescales for Achieving WFD Status Objectives

It is considered that for water bodies that have not achieved their WFD status objectives, clarity and transparency on the progress projected during the next cycle should be a component of the 3rd RBMP. This has arisen from a concern within the membership of An Fram Uisce regarding the lack of information on and monitoring and evaluation of progress on the principal actions of the current RBMP.

It is understood and accepted that time delays for improvements in water quality are often unavoidable. However, an analysis of and an estimation of these time delays is essential not only for communication purposes, but also to assist work and resource planning and to enable projections on dates for restoration to the required water body status.

2.1.5.1 Factors determining time delays for improvement

The factors considered relevant to estimating time delays are illustrated in Figure 1 below.

To provide further information on these factors, An Fram Uisce has developed a Briefing Note on

Achieving Water Framework Directives: The issue of time delays – How long will it take for improvements to occur? This briefing note is available at: https://thewaterforum.ie/app/uploads/2020/06/Time-Delays_May2020.pdf.

The Briefing Note provides a means of estimating time delays for improvement for water bodies impacted by two significant issues – phosphate and nitrate. The Briefing Note provides a systematic approach for determining time delays and projected dates for achieving the WFD status objectives for At Risk water bodies, which can either be used directly or in an amended form.

To account for time delays in communicating progress on the 2nd RBMP and for implementation of the 3rd RBMP, the following recommendations are made for monitoring, evaluation and reporting:

•

An analysis of the likely time delays for improvement in the water quality of water bodies that have not achieved their status objectives by 2021 be undertaken.

•

The projected date for achievement of the of status objective for each water body should be provided together with reasoning for this projected date.

•

Trend analyses are undertaken as an indicator of improvements that can then be reported to bodies such as An Fram Uisce during the next cycle.

•

If necessary, appropriate additional monitoring is carried out to assess the effectiveness of mitigation measures and actions so that adjustments can be made if the projected improvements are not occurring.

Implementing the above recommendations would assist in supporting the development and implementation of SMART objectives for planning and particularly resource allocation with regards to the 3rd RBMP cycle.

Figure 1: Schematic showing the major elements of the potential time delay for water quality improvement, including policy development and implementation component, catchment time lag components and the time needed to undertake monitoring.

2.1.6 Climate Change

The impacts of climate change on Ireland’s water resources may be multi-factorial as drought magnitude and duration may increase in the future, and Ireland has been identified as one of six European countries where the impact of a +2°C global warming will be most extreme20. Weather extremes and climate variability directly impact the hydrological cycle, potentially resulting in

20 Roudier, P., Andersson, J.C.M., Donnelly, C., Feyen, L., Greuell, W. and Ludwig, F. (2016). Projections of future floods and hydrological droughts in Europe under a +2°C global warming. Climatic Change 135: 341-355. doi: 10.1007/s10584-015.1570-4.

consequences for both social and economic factors21. Future climate change projections for Ireland include: an increase of mean annual temperatures of 1-1.6°C; an average increase in the growing season by over 35 days per year by the mid-21st Century; significant decreases in average precipitation amounts in spring and summer months as well as over the full year; an increase in heavy precipitation events; and a substantial increase in the number of extended dry periods22. Water resources have been identified as being vulnerable to future climate change scenarios for Ireland23, and a number of hydrological changes (such as reduced soil moisture storage; lower groundwater recharge for longer, sustained periods; and changes in streamflow) are predicted to manifest through the increased frequency of major high and low river flow events24.

The SWMI public consultation document correctly identifies climate change as impacting on the quality of Ireland’s water resources, but climate change itself is not considered by this response to be a SWMI. Rather, it is a direct driver of ecosystem change11 which will also have socio-economic consequences which themselves may manifest through changes in water quality and water availability.

Understanding of the effects of social shifts and economic impacts associated with water resources management is needed in addition to understanding the future impacts of climate change25. Ensuring policy coherence of the 3rd RBMP with wider climate-related policies and plans is essential for RBMP measures to increase resilience in Ireland’s water resources and their management (including management of water and wastewater services), and improve public awareness and involvement in water and climate measures.

2.2 Reconceptualising Ireland’s Significant Water Management Issues from an Integrated Land and Landscape Management Perspective

This section introduces the sector-pressure-stressor approach as an alternative for understanding and

managing the Significant Water Management issues which impact on Ireland’s aquatic environments.

Underpinned by the FILLM (Section 1.2), the focus of this approach is to identify the environmental stressors which manifest through water quality and WFD status. It is these environmental stressors which can be considered Significant Water Management Issues. Industry and social sectors contribute to changes in water quality and WFD status through introducing pressures which act on the waters and ecosystems within catchments. These pressures can influence the levels of environmental stressors which, acting either singularly or in multiplicity with other stressors, can result in changes in water quality, ecosystem function, the sequestration of carbon, biodiversity and WFD status.

21 Mehan, S., Kannan, N., Neupane, R., McDaniel, R. and Kumar, S. (2016). Climate change impacts on the hydrological processes of a small agricultural watershed. Climate. 4. Doi:10.3390/cli4040056. 22 Nolan, P. (2015). Ensemble of regional climate model projections for Ireland. Report to the Environmental protection Agency for Ireland.

https://www.epa.ie/pubs/reports/research/climate/EPA%20159_Ensemble%20of%20regional%20climate%20model%20pr

ojections%20for%20Ireland.pdf

23 Coll, J. and Sweeney, J. (2013). Current and future vulnerabilities to climate change in Ireland. Report to the Environmental Protection Agency of Ireland. 24 Sweeney, J., Albanito, F., Brereton, A., Caffarra, A., Charlton, R., Donnelly, A., Fealy, R., Fitzgerald, J., Holden, N., Jones, M.

and Murphy, C. (2008). Climate change – Refining the impacts for Ireland. Report for the Environmental Protection Agency of Ireland.

25 Rolston, A. (2016). Water management: Social changes affect water quality too. Nature 536: 396. doi:10.1038/536396b.

How stressors interact is often dependent on the type of aquatic system in which the stressors are present26. As an example, nutrient pollution is typically the overriding stressor in lake systems. Yet, for rivers, the effects of nutrient pollution may depend on the combination of different stressors as well as how the impact of these stressor combinations is measured. Consequently, lakes and rivers can require different conservation and management processes26. For lakes, the traditional approach of reducing nutrient use and discharge across catchments is key. However, for rivers, more bespoke management approaches are needed which consider the different stressors acting on the system, and how these stressors interact26.

By examining the linkages between stressors, pressures and the sectors through which they are delivered, it is possible to take an integrated, holistic approach to developing and implementing mitigation measures which can also produce co-benefits for climate change and biodiversity.

2.2.1 Examining Sectors, Pressures and Stressors as an Alternative Approach to Addressing Significant Water Management Issues

2.2.1.1 Identifying and managing SWMIs within the Framework for Integrated Land and Landscape Management

The FILLM (Section 1.2) is the underpinning framework for this proposal of using the stressor-pressure.sector model approach to identify and manage Ireland’s Significant Water Management Issues. It enables the management of SWMIs to be broadened to include components of our natural and social environments that may not be included in mitigation efforts through alternative SWMI management approaches. In addition, it enables the policy coherence required for the 3rd RBMP by connecting the various international and national legislative instruments and policies.

The SWMI public consultation document identifies 12 Significant Water Management Issues and two

‘other Issues’ which are impacting on Ireland’s water environment. Some of these Issues can be

considered higher level aspects of water resources management that manifest through various mechanisms and functions to affect water quality and WFD status rather than as specific SWMIs. For example, rather than being SWMIs, Prioritisation and Public Participation (identified as Issue 1 and 2 respectively in the public consultation document) are mechanisms through which improvements in water management governance, water quality and WFD status can be made. Climate Change (Issue 5 in the public consultation document) is an overarching driver of water availability, water quality and biodiversity (as discussed in Section 2.1.6). Addressing climate change within the FILLM requires action for both adaptation and mitigation measures to deliver a resilient landscape.

2.2.1.2 An example of a sectoral contribution within the sector-pressure-stressor approach

Increasing landscape resilience through the FILLM requires an examination of the contributions of different sectors within an Integrated Catchment Management context. To illustrate this proposed

26 Birk, S. et al. (2020). Impacts of multiple stressors on freshwater biota across spatial scales and ecosystems. Nature Ecology and Evolution https://doi.org/10.1038/s41559-020-1216-4

alternative approach to addressing SWMIs, agriculture is used here as an example of identifying sectoral contributions which have implications for land and water management.

Agriculture has featured prominently in previous RBMPs and EPA reports as a pressure acting on our water resources; and agriculture is named in the public consultation document as a SWMI (Issue 4 in the public consultation document). Addressing the agriculture as an individual SWMI creates inherent challenges due to the complexity of the different forms of agriculture, and how they and their different management actions interact with the water environment.

Within the sector-pressure-stressor approach, it is proposed that with regards to water resources management, agriculture should be examined as a sector, the functions of which can manifest as multiple pressures. For example, functions of agriculture include land management, run-off, hydromorphological modifications, water abstraction and wetland degradation. Each of these can be considered as pressures which impact on water quality.

Within the FILLM however, tackling any one pressure should be approached from a perspective of optimising outcomes over a series of pressures.

2.2.1.3 Significant Water Management Issues within the sector-pressure-stressor approach

Examining the SWMI public consultation document and the 2nd RBMP, five environmental stressors can be identified which, either singularly or acting in multiplicity, can result in unsatisfactory water quality and WFD status. These environmental stressors are Sediment, Nutrients (nitrogen, in terms of nitrate and ammonium, and phosphorus), Microbes (bacteria, viruses and parasites), Chemicals and Organic Matter. For some of these stressors there may also be public health impacts associated with their presence in waters.

Three more environmental stressors are considered here to be of importance which are not addressed through the 2nd RBMP and the current SWMI public consultation paper, but which impact on one or more aspects of water quality, WFD status and public health: Microplastics; Water Level and Flow; and Temperature.

Background information and rationale for inclusion of the eight stressors in this proposed approach is included in Appendix 1.

By focusing on the linkages of each of these environmental stressors with the pressures and sectors through which they are manifested, it is possible to create a more holistic picture of the complex

interactions acting on Ireland’s waters.27

27It is recognised that these eight environmental stressors may not be exhaustive, and they may act in combination with other stressors which are not included in this description of this alternative approach to SWMIs. For example, chemicals, sediment, nutrients, microbes, organic matter, water level and flow and temperature all interact with an additional environmental stressor which can have a deleterious impact on water quality and WFD status: dissolved oxygen. In our description of this alternative approach to SWMIs, dissolved oxygen is not included as an environmental stressor as it is not a direct consequence of the pressures identified. Rather, it is a consequence of the interactions of more than one of the eight environmental stressors.

A conceptual diagram of these linkages is provided in Figure 2. The eight environmental stressors are shown at the bottom of the diagram, and each has a defined connection to one or more of ten identified pressures. Each pressure is intrinsically linked to one or more of six sectors. The stressors, pressures and sectors included in this example may not be exhaustive, but are being used as an example as to how, by focussing on the stressors and examining their linkages to pressures and sectors, a more holistic approach to managing Significant Water Management Issues can be developed. The linkages shown in Figure 2 do not attempt to weight the interactions between sectors, pressures and stressors.

Having identified the overarching linkages between all stressors, pressures and sectors, the linkages for singular stressors can be examined (Figure 3). For example, the environmental stressor Nutrients (NO3, P, NH4) is influenced by eight pressures: Wetland degradation, Urban WWTP, Domestic WWTP, Hydromorphological modifications, Run-off (urban and agricultural), Industrial discharges, Land management, and Invasive Alien Species. To manage nutrient concentrations in Ireland’s waters, the FILLM provides a holistic approach to mitigating each of these stressors through integrated management within and between the sectors which influence each of these pressures.

Figure 2: Conceptual diagram of the interactions between environmental stressors, pressures and sectors which, in combination, manifest in water quality and WFD status.

Figure 3: Conceptual diagram of the interactions between the environmental stressor, Nutrients (NO3, P, NH4), and the pressures through which it is manifested, and the sectors which contribute to the pressure.

PART THREE: SIGNIFICANT WATER MANAGEMENT ISSUES

IDENTIFIED IN THE PUBLIC CONSULTATION

DOCUMENT

3.1. Addressing the SWMIs Identified in the Public Consultation Document

The SWMI public consultation document identifies 12 SWMIs and two ‘other issues’ with a number of questions provided for response for each issue. These questions are addressed below within the prism of the FILLM and the sector-pressure-stressor approach presented in Parts One and Two of this response respectively.

3.1.1 Prioritisation

Q: Of the current priorities in the RBMP, which do you consider to be the most relevant?

The Water Framework Directive (WFD) requires all water bodies to achieve good status. As stated in Articles 3 and 4 of the WFD, Member states have an obligation to coordinate programmes of measures for the whole of the river basin district, and that measures should be implemented to prevent deterioration of the status of all bodies of surface water [emphasis added by An Fram Uisce]. Therefore, the prioritisation of measures into 190 sub-catchment Priority Areas for Action (PAAs) undertaken in the 2nd RBMP contravenes Ireland’s obligations under the WFD.

It is recognised that limited resources must be sparingly shared. However, in addition to the contravention of the WFD, the PAA prioritisation process immediately restricted the true implementation of Integrated Catchment Management, so widely championed in the 2nd RBMP. The PAA process failed to take a whole-of catchment approach, instead prioritising areas for action at the sub-catchment scale.

LAWPRO, ASSAP and the DHLGH have recently communicated that some improvements have been observed in water quality and WFD objectives within the PAAs. However, An Fram Uisce is unaware of any definitive quantitative evidence to show that these improvements are a direct result of the engagement activities and measures implemented in the PAAs. This is partly due to the limited monitoring and evaluation of these engagement activities and measures. An Fram Uisce expresses concern that public statements are being made by multiple bodies claiming successes that the LAWPRO and ASSAP programmes are achieving in the PAAs without the evidence available to support such claims.

The EPA have reported8 that water quality overall has continued to decline nationally. Therefore, to adhere to Ireland’s WFD obligations, there is an inherent need to restore water bodies in need; and protect those water bodies that are achieving their WFD objectives.

Local Authorities have responsibility for protecting water quality where it is deemed to be satisfactory. Where water quality is unsatisfactory, LAWPRO are the main public body with responsibility for improving water quality at a local level within PAAs. Therefore, Local Authorities have responsibilities for improving water quality outside of PAAs.

An Fram Uisce expresses concern that the resources allocated to and by Local Authorities to undertake their responsibilities for protecting water quality and improving water quality outside of PAAs are not sufficient to produce the required results. A lack of appropriate training for Local Authority staff accompanies the lack of resource allocation, resulting in the Local Authorities function for protecting water quality being diminished. Consequently, as highlighted by theEPA’s Water Quality Report 2013-201828, water quality is continuing to deteriorate at the national scale.

In addition, An Fram Uisce is concerned about the potential for Local Authorities to appropriate the resources they do have towards issues unrelated to water quality improvements due to a perception that LAWPRO is already undertaking that body of work.

All eight stressors identified in the sector-pressure-stressor approach described in Section 2.2 are linked to drinking water quality. Catchment management measures aimed at mitigating these stressors and their associated pressures will therefore have the additional benefit of drinking water source protection and public health. Consequently, if a revised PAA selection process is to be introduced in the 3rd RBMP, prioritisation should be given to catchments which are used as drinking water sources; and any actions which provide co-benefits for climate change and biodiversity.

Q: Are there any additional priorities you think should be included in this RBMP?

Taking a whole-of-catchment approach to land and landscape management as advocated by the FILLM should be included as a priority in the 3rd RBMP.

Urgently progressing commitments made in the 2nd RBMP, as well as any new commitments introduced in the 3rd RBMP, to improve urban wastewater treatment infrastructure is essential. Including transparent reporting of such progress should also be a priority in the 3rd RBMP. See Section

3.1.12for further detail.

Q: Would you amend any of the existing priorities?

It is difficult to address this question without clear and timely monitoring and evaluation of 2nd RBMP actions. Therefore, the monitoring and evaluation of 1) the actions outlined in the RBMP; and 2) the methods used to achieve these actions should be improved. As mentioned above, a focus on catchments which are used as drinking water sources can maximise co-benefits of ICM and the FILLM approach for drinking water source protection, public health, climate change and biodiversity.

Q: Are there any external factors you think should be considered in setting priorities for this RBMP cycle?

It is unclear what is meant by external factors in this question. Approaching this question from the perspective of factors external to WFD implementation, the integrated approach to land and landscape management as proposed by the FILLM comes sharply in to focus. In order to address the stressors and pressures outlined in Part Two of this submission, the integrated and holistic approach of the FILLM is essential to engage the different sectors that link with the pressures and stressors. Engaging the different sectors will inherently require coordination and collaboration across multiple Government Departments, Agencies, and bodies.

In addition, transparent reporting of progress on the RBMP (i.e. monitoring, evaluation and reporting) should be undertaken for all actions stated in the RBMP; and it should be ensured that all bodies with responsibility for undertaking actions are required to report on metrics aligned with the RBMP actions.

3.1.2 Public Participation

Q: Do you feel people are given the opportunity to engage in the way our waters are managed? Please provide examples to support your answer including ways this may be improved.

People are given the opportunity to respond to the way our waters are managed with little transparency as to whether any responses are incorporated into decision making. Engagement is a two-way process that allows for knowledge sharing and the incorporation of alternative viewpoints into the decision-making process. The way in which water management-related engagement is undertaken, and who is engaged, must be improved, and the FILLM approach explicitly requires public engagement and input at all stages. An Fram Uisce has produced a briefing note on public engagement in water management based on commissioned research on this topic: https://thewaterforum.ie/briefing-note-on-public-participation/. The key recommendations from this briefing note are:

1. Introduce and support public participation processes which incorporate the three key principles of effective public engagement:

. address inequity and power imbalances between different individuals and stakeholder groups . incorporate various forms of knowledge/expertise, in particular to recognise the value of lay knowledge as well as scientific expertise . address issues of scale e.g. how pressures and processes that operate at national levels circumscribe local decision-making regarding water management.

2.

Conduct an evaluation of current engagement initiatives based on the above principles. This should also include an assessment of wider water governance for compliance with good governance principles: accountability, transparency, equity, inclusiveness, responsiveness, effectiveness, and efficiency. This is because such governance is necessary to support public engagement.

3.

Include communities and individuals in procedures and decision-making around water resources from the beginning. This recognises the value of their knowledge early in the catchment management process. It also elicits concerns, connections, and expertise early on and vitally, it builds trust.

4.

Support medium/long-term interdisciplinary research on public engagement including in the form of pilot projects. These should trial a range of approaches, while integrating multiple forms of expertise (e.g. biological; sociological; lay) into scientific research in ways that produce meaningful public engagement. Because this kind of participatory research involves time to establish relations of trust between stakeholders and across disciplines and expertise, medium/long-term institutional and financial supports are essential.

Incorporating social science methodologies and social science expertise to assist in the delivery of water-related engagement is an important factor to improve engagement actions and their monitoring and evaluation. Recognising that resources are limited, there is the opportunity to develop ‘pilot engagement catchments’ where a range of engagement, monitoring and evaluation methodologies are undertaken across different scenarios to understand what engagement practices are successful and which can be improved. Lessons derived from national and international public participation approaches in water resources management can be trialled within these pilot engagement catchments to assess what methods and approaches work or do not work within an Irish context.

Co-designed catchment management plans developed in collaboration with local communities and stakeholders provide an opportunity to help raise awareness of issues occurring within local catchments as well as incorporating local knowledge and solutions into the plans. Such inclusive, co-

design processes could be trialled in the ‘pilot engagement catchments’ proposed above,

incorporating lessons from international case studies where co-design has been implemented in water-resource management projects, for example in the Netherlands and the UK.

Commenting on the content of the SWMI public consultation, An Fram Uisce has significant concerns regarding the technical nature of the questions to which responses have been directed to answer. These questions frequently require detailed environmental knowledge around water management and the individual SWMIs to which the individual questions are addressed. This creates challenges for lay persons to respond to the SWMI public consultation, particularly as preference is stated for responses to be submitted via the online survey portal through which these questions can be answered. Little consideration is given to citizens with limited knowledge of the river basin management planning process or water management in general, but who wish to partake in the public consultation process. This creates an inequity in the public consultation process and it has the potential to reduce the likelihood that less expert citizens will submit a response. This inequity, and the lack of incorporation of lay, non-expert knowledge, are addressed within the recommendations of An Fóram Uisce’s briefing note on public participation, detailed above.

As discussed in section 2.1.3, given its statutory role in water management, it is proposed that An Fram Uisce is appointed as a champion body for the delivery of the SDGs and their water-related actions.

3.1.3 Land-use Planning

Q: How can the planning system be further improved to contribute effectively to the protection and improvement of water resources in Ireland?

The FILLM is an overarching framework for environmental management which connects multiple legislative instruments and incorporates spatial planning. As stated in the FILLM, a spatial planning system is needed that takes account of all environmental components in a holistic and cohesive manner. Reduced compartmentalisation of planning and actions within the various environmental components is needed, as cross-component planning can deliver benefits in terms of cost-efficiency and environmental effectiveness.

Currently, there is no planning guidance for Local Authorities regarding Water Framework Directive concerns and consequently decisions are being made within a knowledge deficit. Planning guidelines for Local Authorities are required, along with training for relevant staff and decision makers involved in planning and WFD implementation.

The recent Programme for Government states multiple commitments relating to land use which are directly applicable to the FILLM, including:

•

Undertaking a national land use review including farmland, forests, and peatlands so that optimal land use options inform all relevant government decisions.

•

Promoting an all-Ireland approach to land use planning and river basin management plans to stop cross-border pollution.

•

Evaluating the potential for contributions towards our climate ambition from land use improvements within 24 months of government formation, and to set in train the development of a land use plan based on this evaluation.

An Fram Uisce welcomes these commitments in the Programme for Government and looks forward to working with the relevant Departments to achieve them.

3.1.4 Agriculture

Q: How can the agricultural sector contribute towards improving water quality?

As described in Section 2.2 of this submission, agriculture has typically been described in previous RBMPs and the SWMI public consultation document as a pressure acting on water bodies. Through the sector-pressure-stressor approach, agriculture is viewed as a sector, the functions of which act as pressures. Delineating the pressures delivered through sectors such as agriculture enables a more targeted approach to reducing the impact of stressors on the water environment.

It is recognised that Irish farmers are required to meet, and through participation in voluntary programmes and agri-environmental schemes often go beyond, EU requirements to maintain farms in Good Agricultural and Environmental Conditions including compliance obligations regarding the management of soils, hedgerows, water courses and fertiliser usage. Yet, it can be argued that some historical policies have resulted in a reduction in the social values associated with water and landscape. The FILLM provides the overarching framework through which action can be taken to ensure that greater value is attributed to water and water-related ecosystems. For farmers currently in receipt of CAP payments, financial rewards are often given for actions which can be detrimental to water-related ecosystems and water quality. Providing incentives that reward the protection and enhancement of water quality and water-related ecosystems will go a long way towards restoring their social and economic value among, not just farmers, but the wider community. Faming for Nature Projects, Results Based Agri-environmental Payment Schemes and EIPs are showing some promising results and such programmes must be further encouraged. Providing public money for public goods can provide support to farmers based on the environmental services they provide as part of their farming.

The EU Green Deal, the EU Biodiversity Strategy for 2030, the EU Farm2Fork Strategy and the reform of the Common Agricultural Policy all provide high level opportunities to revitalise the social and economic value of water quality, water-related ecosystems and the ecosystem services that they provide.

New research28 has identified that Ireland lies 35th out of 38 countries for aligning policy changes with relevant sections of the OECD Council Recommendation on Water and the 2017 G20 Agriculture Ministerial Action Plan on water and food security (Figure 4). The report recommends that relatively water abundant countries such as Ireland should “pay attention to their approach to manage water quantity and risks under climate change, [and] all countries should consider improving their policies to reduce pollution from agriculture”. Ireland should heed this recommendation across water quantity, climate change risks and pollution reduction and the FILLM and the sector-pressure-stressor approaches provide the holistic support necessary to deliver on this recommendation.

The EPA Report on Water Quality in Ireland 2013-20188 identifies that nitrates are increasing in both surface and groundwaters, particularly in the south and southeast of the country. In its submission to DAFM on the Nitrates Derogation Review in May 2019, An Fram Uisce made the following general recommendations for water bodies where nitrate is identified as a significant issue:

•

Source control and mobilisation control measures need to have priority in this situation.

•

Examples for consideration include:

i) Use of protected urea.

ii) Use of clover and over-sowing clover. (While there is evidence that this can be effective both in terms of grass production and reduction of inorganic N fertilizers, it requires more management of the grass sward and of the animals (due to the danger of bloat).)

iii) Applying N fertilizer ‘little and often’ to facilitate N usage.

iv) Introducing incentives for farmers to use slow release fertilizer, e.g. nitrogen inhibitors.

v) Enabling an increase of areas that have environmental services as their objective as a means of diluting nitrate concentrations, while at the same time increasing biodiversity and carbon sequestration.

The Nitrates Action Plan is due for public consultation in 2020 and An Fram Uisce looks forward to engaging with the relevant Departments as part of the NAP consultation process.

28 Gruère, G. et al., (2020). Agriculture and water policy changes: Stocktaking and alignment with PECD and G20 recommendations. OECD Food, Agriculture and Fisheries Paper No. 144. https://www.oecd-ilibrary.org/agriculture-and.

food/agriculture-and-water-policy-changes_f35e64af-en

An Fram Uisce also welcomes the research projects introduced during the course of the second RBMP, such as the SmartBufferz, Slowwaters and Watermarke projects; and looks forward to seeing the results of these projects being used to inform 3rd RBMP measures.

Figure 4: Average alignment of agriculture and water policies with the Council Recommendation on Water by country for (A) ordered by status in 2009; and (B) ordered by status in 2019. Indices range from 0 to 1 with higher indices indicating a higher alignment of policies29.

Q: Do you believe that CAP will have a positive or negative impact on water quality in Ireland?

An Fram Uisce has commissioned a research project entitled “Optimising water quality returns from the reform of the Common Agricultural Policy”. The final report will be available in September 2020 and will provide strong policy analysis around CAP reform and its potential impact on water quality.

As mentioned in the previous question, historical agricultural policies, such as the CAP, have resulted in a reduction in the social and economic value of water and its associated ecosystems, as well significantly contributing to the continued decline in overall national water quality. CAP reform has the opportunity to redress this by providing incentives to maintain, protect and improve agricultural management of water and water related ecosystems while providing important co-benefits for climate and biodiversity. The FILLM provides the overarching framework as to how this can be achieved in a holistic and integrated manner.

Q: Do you think CAP measures to protect water quality should be retained at a national scale or become more locally targeted?

There is no one-size fits all approach to protecting and improving water quality. Agriculture, facilitated by policy, has been identified as a significant pressure acting on water quality nationally. A combination of national and locally targeted approaches will be necessary. National guidance is important, but an opportunity exists for locally targeted approaches in which farmers can decide on which is the best approach to use on their land through knowledge-sharing and co-design principles.

3.1.5 Climate Change

Q: Do you believe the links between climate change policy and water quality can be improved, and if so, have you any suggested on how they could be improved?

Water is often missing from the climate change conversation despite the inherent linkages between the changing climate, water quality and water availability. Increasing the visibility of water within climate mitigation and adaptation measures is an initial step to improving the links between climate change policy and water quality.

As climate change becomes more apparent in Ireland, water availability will become a more frequent issue, as highlighted by two droughts in two years between 2018-2020. Knowledge gaps surrounding abstractions in agriculture, and their cumulative effect within catchments, create difficulties for implementing abstraction legislation into the future. As noted in An Fóram Uisce’s submission in October 2018 to the DHPLG on the consultation process in relation to the Water Environment (Abstractions) Bill 2018 General Scheme, the cumulative impact of abstractions below the threshold for registration is unknown.

Q: Do you consider climate change to be a significant threat to water quality in Ireland?

This submission addresses the impact of climate change on water resources under Section 2.16 and Appendix 1.

3.1.6 Pollution of Waters (phosphorus and nitrogen)

Q: Investing in urban waste water infrastructure and providing free agricultural advisory services are two targeted ways that the last RBMP aimed to reduce nutrient losses to surface waters. What other kinds of measures could be targeted and how?

Progress on the urban wastewater infrastructure commitments made in the 2nd RBMP has been slow, and urgent progress on these commitments is essential to reduce nutrient pollution of our waters. The 3rd RBMP should include statements on the progress made to date on the 2nd RBMP commitments to improving wastewater infrastructure, providing reasons for any lack of progress. This should include updates on compliance and non-compliance of individual WWTPs, projected timeframes for achieving compliance where needed, and an action plan for achieving any 2027 wastewater infrastructure upgrades committed to in the 3rd RBMP. It is not acceptable that 36 agglomerations are without wastewater treatment systems. Urgent action is needed to address this and to ensure that Ireland complies with the UWWT Directive. Currently 58% of the population’s wastewater does not meet EU wastewater treatment standards. Greater innovation is needed to address wastewater in urban areas under 500pe and sustainable urban drainage should be further implemented.

Soft engineering options, such as integrated constructed wetlands, for example, should be included as management options for reducing nutrient pollution at the catchment scale rather than solely relying on WWTP engineered solutions.

Data gaps exist regarding the number of combined sewer overflows and storm water overflows present nationally, their locations, discharge rates and discharge volumes29. The UK Rivers Trust has recently published mapping for all known CSOs and storm water overflows in England30. Funding should be provided to review the current data available for CSOs and SWOs in Ireland with the aim of developing a similar publicly available data-hub to that produced by the Rivers Trust.

The implementation of the recently announced grant system for domestic wastewater treatment systems is welcomed, along with the online interactive map for households to identify if they are eligible for the grant. But An Fram Uisce notes the delay in the implementation of this grant system since its inclusion in the 2nd RBMP in 2018. The grant system must be continued into the 3rd RBMP.

Greater transparency in reporting of progress against RBMP measures and actions is necessary. In communications with An Fram Uisce, Irish Water have confirmed that their monitoring and evaluation and reporting metrics regarding wastewater infrastructure are not aligned to the 2nd RBMP. This impedes the monitoring and evaluation of the RBMP and inhibits transparency on progress on commitments made.

Nutrient recovery from wastewater and its recycling into agriculture has the potential to both reduce nutrient pollution of water bodies and reduce use of, for example, mineral phosphorus as land fertiliser. Further research into the efficacy and contaminant removal from wastewater sludge for recycling is necessary as are measures and policy to further encourage the recovery and recycling of nutrients from wastewater31.

In addition, further research into alternative waste recovery and recycling methods are required, with consideration given to revision to Part H of the Building Regulations to facilitate domestic urine separation and toilet composting where feasible and appropriate.

The initiation of EPA-funded research projects, such as the SLAM Project regarding load apportionment, are welcomed and the results of such research must be used to inform the

29 Morgan, D., Xiao, L. and McNabola, A. (2018). Technologies for monitoring, detecting and treating overflows from urban wastewater networks. Report to the Environmental Protection Agency of Ireland. Available from:

http://www.epa.ie/pubs/reports/research/water/Research_Report_240.pdf

30https://www.arcgis.com/apps/webappviewer/index.html?id=a6dd42e3bc264fc28134c64c00db4a5b&extent=146436.957

6%2C27590.8012%2C854242.0922%2C563326.0668%2C27700

31 Ryan, M.P., Boyce, A. and Walsh, G. (2016). Identification and evaluation of phosphorus recovery technologies in an Irish contentxt. Report to the Environmental protection Agency of Ireland.

https://www.epa.ie/researchandeducation/research/researchpublications/researchreports/EPA%20RR%20189%20final%20

web.pdf

development of the 3rd RBMP. Further such research must be prioritised to increase the evidence base around nutrient pollution.

An Fram Uisce recommends that while nutrient management planning is an important means for reducing nutrient losses from land, pathway interception measures should be prioritised for mitigating impacts from phosphate, and source reduction and mobilisation control measures should be prioritised for mitigating impacts from nitrate.

3.1.7 Physical Changes to Surface Waters/Hydromorphology (including barriers to fish migration)

Q: How can natural processes in waters be protected and restored?

Physical changes to surface waters have often been implemented due to previous legislation, such as the Arterial Drainage Act 1947, policies and incentives for undertaking bodies of work. To redress some of the physical changes made, consideration needs to be given to the mechanisms through which incentives can be applied to deliver the changes required. Other barriers to facilitating restoration works also need to be examined, for example the planning process for undertaking river restoration works.

In addition, there are no guidelines for assessing hydromophological impacts on waters in the planning process, and these should be introduced.

Q: Do you think that natural water retention measures, i.e. slowing the flow, should be explored further? How could these types of measures be implemented?

Yes, natural water retention measures must be, not just explored further, but incorporated as options for catchment-scale flood mitigation measures and habitat restoration measures. The FILLM provides the holistic framework for environmental management, connecting legislation including the Floods Directive. Inter-agency collaboration is necessary for the design and implementation of these types of measures, along with shared and coordinated policies.

Lessons from international best practice and case studies of successful implementation of natural water retention measures should be incorporated into any plans for delivering such measures. Examples of best practice include the Scottish Environmental Protection Agency Natural Flood Management Handbook32 and successful implementation of such measures include those presented at the EPA Water Conference 2020 by Hamish Moir of the Rivers and Lochs Institute, University of the Highlands and Islands, Scotland; and Mary-Liz Walshe of Dublin City Council33.

Q: How should existing barriers to fish migration be prioritised for mitigation (either removal or modification to improve fish migration and natural processes)?

Those rivers where migratory fish populations are in crisis in comparison to historical figures and where barriers to fish migration have been found to be a significant contributary factor to the population declines should be prioritised for action.

32 https://www.sepa.org.uk/media/163560/sepa-natural-flood-management-handbook1.pdf

33 https://www.catchments.ie/2020-epa-water-conference-watch-online-now/

Progress on the actions stated in Ireland’s National Biodiversity Action Plan 2017-202134 should be reviewed and lessons learned, and knowledge gaps identified to inform the actions required through the 3rd RBMP to help achieve the Biodiversity Action Plan.

3.1.8 Siltation

Q: Would you consider source control measures, such as catch crops for tillage and appropriate riparian margins, to prevent soil loss (silt and nutrients) from land and increase biodiversity?

These measures could be included as part of individual catchment management plans for each RBMP catchment where appropriate. Developing such catchment management plans in collaboration with local communities and stakeholders would help raise awareness of issues occurring within the catchment as well as incorporating local knowledge and solutions into the plans. The FILLM provides the supporting framework for the integrated development of catchment management plans.

Pathway interception measures are important for the management of siltation in addition to being important for nutrient management as stated under section 3.1.6. A targeted approach to pathway mitigation is likely to achieve greater results than a one-size-fits all approach.

Q: Would you consider developing a land management plan to reduce silt and nutrient losses to waters? This could include measures such as drainage towards naturally wet low-lying areas; the use of drain blocks/silt traps?

As for the previous question, these measures could be included as part of a catchment management plan co-developed by the local communities and stakeholders for each individual catchment, for which the FILLM provides the supporting framework.

Q: What else should we consider?

Sediment is identified in this submission as a stressor (see Section 2.2 and Appendix 1). Using the sector-pressure-stressor approach as advocated in this submission enables the issue of siltation to be addressed in a holistic and integrated manner within the context of the FILLM.

3.1.9 Public Health/Drinking Water Quality

Q: What can we do to improve the resilience of our drinking water supplies and their associated ecosystems? How can climate change impact on this resilience?

The vulnerability of the drinking water supply for the Greater Dublin area was highlighted by the outages at the Liffey water treatment plant which affected 600,000 on two separate occasions in 2019. Increasing the diversity of supply to the Dublin area is essential as are infrastructure upgrades to increase headroom in water treatment plants.

Irish Water’s preferred option for diversifying supply is the Eastern and Midlands Supply Project. If the project is approved to proceed, it may take more than 10 years to be completed. In the meantime, it is feasible that the country will face further water shortages following two droughts in two years. An

34https://www.npws.ie/sites/default/files/publications/pdf/National%20Biodiversity%20Action%20Plan%20English.pdf

Fram Uisce provided a submission to the CRU on the proposed Eastern and Midlands Supply Project in June 2019.

Irish Water is aiming to reduce leakage from the current 43% to 38% in 2021 following a €500 million investment. Recognising that further resources and time are necessary to reduce leakage rates further, An Fram Uisce presses for greater ambition to reduce leakage below 38% post 2021. Given the wide range of infrastructure upgrades required nationally, the regional population growth projections and the expenditure controls applied by the CRU for the period 2020-2024, An Fram Uisce has concerns regarding achieving further ambitious targets to increase the resilience of drinking water supplies. Leakage reduction will reduce water demand, but will not, on its own, address the issue of water security and water resilience.

Climate change will undoubtedly impact on the resilience of Ireland’s water supplies, directly through water availability (both high and low flow scenarios), water quality; and indirectly, for example, as projected temperature increases in surface waters are expected to increase the potential for disinfection by-products such as Trihalomethanes35. Comment on climate change in the context of the SWMI public consultation document, the sector-pressure-stressor approach and the FILLM is provided in Section 2.1.6 of this submission.

The resilience of ecosystems which are used as drinking water supplies is dependent on their ecological character and, in the case of surface water supplies, the maintenance of flow and water level regimes. A whole-of-catchment cumulative approach to abstraction licencing should be undertaken, with due consideration to the impact of abstractions on ecological character and flow and water level regimes.

Q: Who should implement drinking water source protection? How can a collaborative approach in the catchments be fostered? How can we engage with landowners and the wider public?

A collaborative approach to drinking water source protection is essential to deliver Integrated Catchment Management through the FILLM. Such a collaborative approach can only be fostered through clear and strong governance, defined roles for action, and appropriate resourcing. Key lessons can be drawn from the two Drinking Water Phase II Source Protection Pilot Projects implemented by the National Federation of Group Water Schemes, as well as the large body of work undertaken by the NFGWS to deliver Phase I drinking water source protection assessments for all Group Water Schemes.

Irish Water has a defined role in developing the National Water Resources Plan and in implementing Drinking Water Safety Plans. The utility has recently begun the process of implementing source protection pilot projects across a small number of catchments, and this is welcomed. Clarity is needed as to how the National Water Resources Plan and the Drinking Water Safety Plans in development by Irish Water link to the 3rd RBMP and catchment-scale objectives.

35 Valvidia-Garcia, M. et al. (2020). Predicted impact of climate change on trihalomethane formation in drinking water treatment. Nature Scientific Reports 9. https://www.nature.com/articles/s41598-019-46238-0

Engagement with landowners and the general public on water related matters is currently the role of LAWPRO and ASSAP, and these two bodies seem to be collaborating well. Yet, deficiencies in the monitoring and evaluation of engagement actions mean that it is difficult to identify the true impacts and results of engagement actions undertaken to date. As advocated in Section 3.1.2 of this

submission, there is the opportunity to develop ‘pilot engagement catchments’ which incorporate

social science expertise and methodologies to deliver Integrated Catchment Management within the FILLM.

Small Private Supplies are consistently shown to have lower drinking water quality than public supplies, publicly-sourced Group Water Scheme supplies and privately-sourced Group Water Scheme supplies. A greater focus on improving water quality in Small Private Supplies is needed and the National Federation of Group Water Schemes Framework for Drinking Water Source Protection36 would assist this. In addition, greater awareness of the importance of drinking water source protection within the Small Private Supplies sector is necessary.

Q: How can we realise co-benefits from source protection including for biodiversity and climate?

Many aspects of the FILLM and consequently Integrated Catchment Management can be achieved through drinking water source protection actions. In particular, An Fram Uisce recommends adopting the National Federation of Group Water Schemes Framework for Drinking Water Source Protection36, which emphasises the importance of co-benefits in protecting drinking water sources, and which applies the FILLM approach to source protection.

Within the sector-pressure-stressor approach of Section 2.2 of this submission, all of the stressors have a direct link to drinking water quality; and drinking water source protection measures aimed at mitigating the pressures acting on the stressors could also provide co-benefits for biodiversity and climate. For example, a national peatlands rewetting strategy would reduce sediment entering water courses and reduce dissolved organic carbon concentrations (leading to fewer lower concentrations disinfection by-products, such as Trihalomethanes, in drinking water supplies), while providing co-benefits for flood alleviation (by slowing the flow), carbon sequestration, and biodiversity through peatland rehabilitation.

Q: How would you describe our attitudes to water usage and the value of water? How could we develop this area?

This is a key component of An Fóram Uisce’s role and is incorporated into its Strategic Plan. An Fóram Uisce is committed to working with all stakeholders to increase the social value of water and to help raise awareness to create water-wise communities. A number of awareness and engagement initiatives are being planned by An Fram Uisce and collaboration with the DHLGH and other stakeholders in the delivery of these initiatives would be warmly welcomed.

36 https://nfgws.ie/a-framework-for-drinking-water-source-protection-2/

3.1.10 Invasive Alien Species

Q: In your opinion, what invasive species are the biggest concern in Ireland?

For species that have yet to arrive in Ireland, recent horizon-scanning research37 has identified the invasive species of greatest concern to experts and stakeholders working in invasive species management. Priority should be given to addressing management actions required to reduce the likelihood of introduction and spread of those species identified in this research (Appendix 1).

Q: What more could be done to help prevent the introduction and spread of riparian invasive species at a national level and a local level?

At a local level, easily accessible funding could be provided to local community groups, such as River Trusts and Catchment Partnerships and Associations to map riparian invasive species presence within their catchments and to develop invasive species management plans to implement the appropriate management measures to reduce their prevalence and potential to spread.

At the national level, clear and transparent governance structures for invasive species management are necessary. This needs to be combined with active engagement measures to raise awareness of local IAS issues, preventative measures and activities associated with the spread of IAS.

An Fram provided the following in its submission under the public consultation for the National Marine Planning Framework under the Descriptor Non-Native Invasive Species. The content is highly relevant to RBMP measures to address IAS and highlights the necessary policy coherence required to deliver integrated management of IAS in Ireland:

Minimising the introduction and spread of NIS is key to achieving and maintaining Good Environmental Status. Public consultation and awareness raising is a key component of this, and An Fram Uisce proposes a targeted information campaign across all relevant stakeholders highlighting the actions necessary to minimise introduction opportunities and spread of NIS.

In order to coordinate such a public awareness campaign, clear and transparent governance structures are required for NIS management and to assist in the implementation of actions outlined in the National Biodiversity Action Plan. Such governance structures should include

1.

An overarching lead authority/body/agency for the management of NIS in marine, transitional and freshwater environments (recognising that the National Biodiversity Action Plan identifies Inland Fisheries Ireland as the lead agency for aquatic invasive species).

2.

Clearly defined roles for all agencies and management working groups/taskforces within the governance structure.

3.

Realistic, integrated national action plans aim to minimise the introduction and spread of NIS in marine, transitional and freshwater environments.

37 Lucy, F. et al. (2020). Horizon scan of invasive alien species for the island of Ireland. Management of Biological Invasions. International Journal of Applied Research on Biological Invasions 11: 155-177.

https://www.reabic.net/journals/mbi/2020/2/MBI_2020_Lucy_etal.pdf

4. Strong policy coherence and integrated management across marine, transitional and freshwater environments.

To support the actions undertaken within this governance structure, greater scientific understanding is required to inform public awareness campaigns in terms of:

•

The prevalence, distribution and risk of spread of established NIS present in marine waters (with the same information available for transitional and freshwater NIS also, delivered through the governance structure and policy coherence recommended above).

•

The prevalence, distribution and risk of spread of newly introduced NIS.

•

An assessment of risk of introduction of NIS not yet present in Irish marine/transitional/freshwater environments, and mitigating actions to prevent their introduction and spread.

The non-native species risk assessments undertaken by IFI and the National Biodiversity Data Centre (http://nonnativespecies.ie/risk-assessments/) should be frequently updated, and expanded beyond those undertaken for non-native species which are subject to trade or potentially subject to trade.

Ensuring direct legal provision in Ireland of the Ballast Water Convention should be undertaken as a matter of urgency.

The European Commission Council Regulation 708/2007 concerning the use of alien and locally absent species in aquaculture should be strictly enforced.

Addressing the above items through the FILLM enables an integrated approach to be undertaken in collaboration with the sectors identified in Part Two of this submission which contribute to the IAS pressures acting on water bodies, and consequently addressing the stressors which IAS influence.

Q: How can the awareness of invasive species at a local level be improved?

Local community and sporting groups could be engaged through a national campaign to raise awareness of local IAS issues, preventative measures and activities associated with the spread of IAS. This can be facilitated through new, improved governance structures and appropriate resourcing as outlined above.

3.1.11 Hazardous Chemicals

Q: How can information on current sectoral pesticide usage statistics (Agriculture, local authorities, forestry, amenities and domestic (home and garden)) be improved to help in assessing risks to water in catchment areas?

It is not possible to fully answer this question without being aware of the current sectoral pesticide usage statistics and how they are communicated. To assess risks to water in catchment areas requires a detailed understanding of, for example, land use, topography, soil type, geology, field and drain connections to waters in addition to the likelihood of pesticide application and amount of pesticide to be applied. Even if a catchment pesticide risk map to waters can be established for catchments, it

doesn’t account for human behaviour actions, for example where an individual rinses out a pesticide

container in a local drain or stream resulting in wide-spread contamination of waters in that catchment.

Q: How can citizen’s behaviour regarding the safe disposal of medication be influenced and changed? What other measures can be taken to prevent medications from ending up in wastewater treatment plants?

Influencing behavioural change is only likely to be achieved if there is an understanding of risk to and by the user or target population. Therefore, public awareness campaigns and labelling information are important, and lessons can be learned from other campaigns such as Think before you Flush.

Q: How can consumer choice be better guided towards choosing personal care products that

don’t impact negatively on the water environment?

Public awareness campaigns and effective labelling are important for influencing consumer choice, but price is the over-riding factor. If personal care products which impact negatively on the water environment were more expensive, for example due to a levy, then it would help drive consumer choice to those products that cause less negative impact. Policy and legislation are also important, as has been observed regarding microplastics/microbeads in personal care products (Appendix 1).

3.1.12 Urban Pressures

Q: How can Green infrastructure be best applied in Ireland to benefit water quality and the alleviation of flooding in towns and cities?

Lessons can be learned from international best practice to create and deliver guidance on design and implementation of green infrastructure and sustainable drainage systems, such as that recently produced by the RSPB and Wildfowl and Wetlands Trust in the UK38. Policy and resources need to be devoted by Local Authorities to further install such green infrastructure in urban areas to slow the flow while creating co-benefits for biodiversity and society.

Catchment-scale flood alleviation requires a greater focus on natural water retention measures to be used in combination with harder engineering flood alleviation measures where deemed appropriate and subject to the required legislative environmental assessments.

At the individual householder scale, the opportunity for increasing rainwater harvesting and greywater recycling exist. But Ireland’s building regulations need revision to facilitate national-scale action to reduce water consumption. Opportunities for retrofitting also need to be pursued. In the UK, current building regulations state that all new homes should be built to a water consumption standard of 125 litres per person per day, with an optional requirement of 110 litres per person per day in water stressed areas where there is a clear need. In Ireland, the average person uses 129 litres of water per day and encouragement is needed to increase water conservation measures.

In 2015, the €100 Water Conservation Grant for all households registered with Irish Water, promoted household expenditure on water conservation measures. No audits were held regarding the use of this grant which was suspended in 2016, and no further grants to enable domestic water conservation

38 https://www.rspb.org.uk/globalassets/downloads/documents/positions/planning/sustainable-drainage-systems.pdf

measures have been introduced since. Consequently, there is little stimulus for the general public to initiate domestic water conservation measures or install domestic green infrastructure which could help to both slow the flow and improve water quality.

Q: What are the particular issues associated with river restoration in urban rivers, and are we applying appropriate actions?

Where possible, opportunities to create green and blue spaces around water courses that would create environmental and societal co-benefits should be prioritised ahead of culverting or other hard engineering solutions. Such spaces have been shown to promote mental and physical health, and reduce morbidity and mortality by providing psychological relaxation and stress alleviation, simulating social cohesion, supporting physical activity and reducing exposure to air pollutants, noise and excessive heat39. Irish-focused research on green-blue infrastructure40 should be used in combination with lessons from international case studies41 42 which successfully delivered such infrastructure should be used to inform recommendations for its delivery through the 3rd RBMP in Ireland.

Q: Are there any additional concerns in relation to urban pressures that are currently not being considered in Ireland?

The economic impact of the COVID-19 pandemic on funding availability for Irish Water to urgently progress and complete their commitments on upgrading urban wastewater treatment infrastructure needs clarification. An Fram Uisce considers it essential for the appropriate funding to be delivered to ensure no impairments of Irish Water’s ability to meet their commitments on this matter.

Q: What other actions do you think could be put in place to reduce the pollution of waters caused by urban pressures?

As mentioned above, revision of the Building Regulations to encourage increased rainwater harvesting and greywater recycling is necessary. Further actions are necessary, including:

•

Ambitious standards for water consumption for new build houses, with consideration for stricter standards in current and future water-stressed areas.

•

Adoption of water quality standards for water recovered from waste streams for reuse, addressing the different purposes for reuse rather than a single standard for all recovered water.

•

Implementation of a water conservation scheme for houses in addition to or incorporated into the Building Energy Rating (BER) Scheme.

•

More stringent standards under Technical Guidance Document G, Section 2.2 to encourage installation of water conserving fittings and water saving appliances particularly for current and future water-stressed areas.

39 https://www.euro.who.int/en/health-topics/environment-and-health/urban-health/publications/2016/urban-green.

spaces-and-health-a-review-of-evidence-2016

40 http://www.epa.ie/pubs/reports/research/health/Research_Report_264.pdf

41 Well, F. and Ludwig, F. (2020). Blue-green architecture: A case study analysis considering the synergetic effects of water and vegetation. Frontiers of Architectural Research 9: 191-202.

https://www.sciencedirect.com/science/article/pii/S2095263519300822

42 O’Connell, E.C. et al. (2017). Recognising barriers to implementation of blue-green infrastructure: A Newcastle case study. Urban Water Journal 14: 964-971 https://www.tandfonline.com/doi/full/10.1080/1573062X.2017.1279190

•

Administering grant aid for retrofitting water conservation measures for existing housing, including rainwater harvesting systems and grey water reuse systems, with consideration for additional aid in current and future water-stressed areas.

•

Developing a national programme across multiple stakeholders for identifying domestic misconnections where household wastewater ends up in the surface drainage system rather than in sewers. Learning from the experiences of the UK Rivers Trusts, for example through their ‘Outfall Safari’43 programme could be beneficial.

3.1.13 Other Issues – Aquaculture

An Fram Uisce recognises that aquaculture is an important component of the Irish coastal economy, providing multiple socio-economic benefits, and aquaculture and fisheries are included as a sector in the sector-pressure-stressor approach outlined in Section 2.2 of this submission.

The following was provided in An Fóram Uisce’s response to the public consultation on the draft National Marine Planning Framework (dNMPF). As stated for Invasive Alien Species, the content is highly relevant to RBMP measures and highlights the necessary policy coherence required to deliver integrated management through the FILLM.

The dNMPF states that increased intensity of storms and the frequency of storm surge ‘will result

in damage to vessels and infrastructure including gear loss in inshore and coastal sector of fisheries

and aquaculture’ (dNMPF, p. 62). Evidence from Coastwatch shows that aquaculture is becoming

an increasing source of marine litter in the Irish environment, yet the OSPAR litter monitoring activities undertaken for the MSFD do not assess litter present in estuarine/transitional waters and no OSPAR marine litter survey locations are close to areas where aquaculture is present. Therefore, the formal reporting of marine litter under the MSFD significantly underestimates the contribution of the aquaculture sector to marine litter.

In addition, aquaculture represents a significant threat to native species – not only, for example, through escaping farmed fish impacting on wild populations; but also through nutrient impacts, disease, marine litter, and the introduction and spread of NIS. The Pacific oyster is a NIS commonly cultivated for aquaculture and despite assurances that this species will not become a problem invasive species in Ireland due to low water temperature, it has already become naturalised in Irish waters (for example, in Lough Foyle). Therefore, cumulative impact of aquaculture should be included in the aquaculture licencing system and the aquaculture planning application process. An Fram welcomes the proposed ecosystem-based approach to the assessment of proposals, but guiding clarification for this approach is necessary.

The focus of the Department on elimination of the aquaculture licencing backlog following recommendations from the 2016 Review of the Aquaculture Licencing Process is understandable,

‘having an immediate beneficial effect on every individual aquaculture operator’ (dNMPF, p.92).

This elimination process should not be undertaken to the detriment of the environment, and all

43 https://www.theriverstrust.org/2019/07/18/drain-misconnections/

relevant legislation and enforcement should be adhered to. Again, An Fram Uisce considers that a cumulative impact assessment in the licencing process is essential.

Aquaculture appears to not be included in the draft Marine Planning and Development Bill and therefore it is unclear how the NMPF, including provisions regarding aquaculture, will be fully implemented through the Bill.

The dNMPF states that ‘Eutrophication can have an adverse impact on aquaculture…’ with land-based sources identified as the causes of this eutrophication. It should also be recognised that aquaculture can be a source of nutrients entering the local environment with, for example, uneaten feed and fish wastes from finfish farms being a source of organic nutrients.

Addressing the above items through the FILLM enables an integrated approach to be undertaken to mitigate the pressures acting on water bodies through the aquaculture and fisheries sector and consequently addressing the stressors which this sector influences.

Regarding the clearance of the aquaculture licencing backlog, An Fram Uisce expresses concerns that many aquaculture operations were able to continue operating without a licence due to a loophole in the Fisheries Amendment Act which allows continued operation once a licence renewal has been applied for. In addition, the speedy process at which the backlog was eliminated provided local communities with little opportunity to take part in the public participation process.

Regarding nutrient inputs from aquaculture, An Fram Uisce highlights that pseudofaeces, faeces and silt from shellfish aquaculture can also have detrimental impacts on the local environment through anoxia and reduction in faunal abundance and diversity.

3.1.14 Other Issues – Antimicrobial Resistance (AMR) Bacteria in Waste Water

Further understanding is needed on the prevalence of AMR bacteria in wastewater in addition to the pathways through which they can present a public health threat – e.g. contamination of drinking water, bathing/recreational waters, etc. A One Health approach44 is required to reduce both water contamination risk from wastewater treatment discharge and public health risk from contact with contaminated waters. Both the One Health approach and the FILLM require multidisciplinary, integrated cooperation of multiple stakeholders across human and animal health sectors, agriculture, environmental management and water and wastewater services.

3.2. SWMIs Not Identified in the Public Consultation Document

It is considered that some important items are omitted from the SWMI public consultation document:

1. Governance. Delivering water resources management through clear, transparent and integrated governance is essential. Section 2.1.1 of this submission briefly details how aspects of governance can be improved for the 3rd RBMP. Considering that the 2nd RBMP introduced a new governance structure, and that a current review of governance is being undertaken by

44 https://www.who.int/news-room/q-a-detail/one-health

the IPA-EPA Experimental Governance project, it is surprising that governance did not feature prominently within the SWMI public consultation document. The FILLM provides a governance approach to land and landscape management through broadening Integrated Catchment Management. And this should be incorporated into the 3rd RBMP.

2.

Coastal Issues. The WFD includes transitional and coastal waters to one nautical mile, yet coastal issues are poorly represented within the SWMI public document. The non-land-based pressures on our coastal zone in particular need to be addressed.

3.

Forestry. Page 17 of the SWMI public consultation document identifies Forestry as a pressure acting on Ireland’s waters, yet linkages to this pressure are limited throughout the document. Forestry is included as a sector in the sector-pressure-stressor approach described in Section

2.2 of this submission (Appendix 1).

4.

Microplastics. There is mounting evidence that our river catchments and transitional and coastal waters are heavily impacted by microplastic pollution from a number of sources including wastewater treatment plants, road run-off, industry, agriculture, aquaculture and domestic appliances. Yet there is no reference to this issue in the SWMI public consultation documents. Microplastics are included as a stressor in the sector-pressure-stressor approach described in Section 2.2 of this submission (Appendix 1).

5.

Water level and water availability. These are likely to be impacted by factors such as climate change and abstraction and will in combination manifest issues in relation to water quality, ecological status, drinking water quality and availability, irrigation and flooding. Water level and water availability are included as a stressors in the sector-pressure-stressor approach described in Section 2.2 of this submission (Appendix 1).

6.

Peat extraction. The extraction of peat is detrimental to the ecosystem functioning of peatland environments and can impact on a number of aquatic stressors as identified in section 2.2, including sediment and organic matter. These stressors have implications for environmental condition of aquatic ecosystems as well as for drinking water treatment processes and drinking water quality, and consequently public health.

7.

Unregulated wetland/peatland drainage. Planning permission is required to drain or reclaim a wetland for the purpose of agriculture where the impacted area exceeds 0.1 hectares or the works may have a significant effect on the environment. The drainage or reclamation of wetlands below the planning threshold at not addressed in the SWMI public consultation document.

Appendix 1: Background information and justification for selection of stressors

Section 2.2 of this SWMI submission provides a reconceptualization of Ireland’s SWMIs within the

Framework for Integrated Land and Landscape Management (FILLM) presented in PART ONE. This reconceptualization identifies the sector-pressure-stressor approach as an alternative to addressing Significant Water Management Issues, identifying eight stressors which, either singularly or acting in multiplicity, can result in unsatisfactory water quality and WFD status.

The information on, and the rationale for selecting each of these eight stressors is provided below.

Sediment

Work being carried out by LAWPRO during the 2nd RBMP Cycle has identified sediment in streams as a significant stressor on the water environment. Sediment is derived from weathering and erosion of bedrock and stream banks. Sedimentation impacts on the biodiversity of the river by reducing habitat diversity within the stream channel and preventing the establishment or persistence of sensitive macro-invertebrate species, resulting in an overall reduced ecological status.

Pressures acting on water resources which can result in increases in sediment include wetland degradation, hydro-morphological modification, run-off from agriculture and urban areas, historically polluted sites, industrial discharge, land management and non-indigenous species.

Sediment fingerprinting research undertaken by Teagasc, as outlined in the SWMI public consultation document, has identified the primary sources of sediment as being channel banks, roads, and runoff from agricultural land. Additional sources of sediment include poorly managed forests, peat extraction, and land management actions such as livestock poaching, riverbank erosion and runoff from ploughed fields. Management of poorly drained land is also important with regards to sediment loading in water as land drainage and channelization can be responsible for 86% of hydro-morphological pressures.

Land management practice is therefore key to reducing sediment loading in waters, with management actions such as planting deeper-rooted grasses, fencing and riparian buffer strips and planting hedgerows helping to intercept the pathway for sediment entering water courses. Some land management actions, such as the establishment of wetlands, can also provide additional co-benefits to reducing sediment loads, such as carbon sequestration and increasing biodiversity.

Recent EPA research projects such as (COSAINT, DETECT, and SILTFLUX) will help identify potential actions to minimise sedimentation pressures on water bodies. ASSAP and Teagasc advice to farmers to manage sedimentation issues will be important as part of the third cycle RBMP.

Nutrients (NO3, P, NH4)

Excess nutrients in waterways result in eutrophication of ecosystems resulting in the growth of algae and plants that can lead to a reduction of oxygen levels in the water. Nutrient enrichment is also a potential human health indicator in drinking water. Nutrient enrichment impacts negatively on fish and macroinvertebrates that could otherwise potentially thrive. Macro-invertebrates as an individual element or in combination with others are responsible for determining ecological status in 91% of monitored river waterbodies. This assessment method (Q-value) is most sensitive to ecological changes caused by organic pollution and nutrient enrichment. As shown in Figure 5 of the EPA Water Quality Report 2013-20188, nutrient conditions, phosphorous and nitrogen were responsible for moderate or less water quality (unsatisfactory) in a significant number of monitored waterbodies. For Phosphorus, 45.8% of monitored sites (260 rivers) were less than satisfactory, and for N 42.8% of monitored sites (239 rivers) were less than satisfactory.

Figure 5: Nutrient conditions, phosphorus and nitrogen were responsible for less than satisfactory ecological condition for a large number of monitored water bodies8.

Pressure acting on water resources which can result in excess nutrients include diffuse sources from agriculture (overland flow and leaching), and point sources including urban and domestic wastewater treatment plants. Diffuse-source pressures are not uniform across the country as a result of being associated with soil type and topography. For example, nitrogen levels are a particular issue for water bodies in the south east of Ireland; whereas phosphorous is more of an issue in the north-midlands where soils are more clay-rich.

Excess nutrients in rivers also impact on coastal areas causing enrichment in transitional zones.

Wastewater treatment systems (domestic and urban) can release nutrients into our waterways and continued investment in wastewater treatment systems and networks is required to mitigate this issue.

An additional long term goal to help achieve the Circular Economy and to help address the limited global supply of rock phosphorus, is for measures and legislation to encourage the recovery, and recycling of nitrogen and phosphorus from wastewater back to agriculture without the presence of toxic metals or pharmaceuticals.

Microbes, Bacteria, Parasites and viruses

Pathogens microbes such as bacteria, parasites and viruses are organisms capable of causing infection or disease in other organisms, including humans, wild and domestic animals, and plants. Several pathogens naturally occur in livestock and poultry manure and under certain circumstances may pose a risk to human health. Many water-borne parasites are often present in animal manure, such as Cryptosporidium, and Giardia.

Contamination of drinking water supplies by microbes, parasites and bacteria is a risk to human health. Bacteria such as E. coli can cause illness, and in a small number of cases it can result in severe and long-term kidney failure with older people and young children being particularly vulnerable to infection. Reported cases of VTEC1, a dangerous form of E. coli, increased in 2018. Public water supplies are regulated for such contaminants but one million people in Ireland obtain their water from private supplies many of which are unregulated and unmonitored. Of these supplies that are monitored private supplies have the lowest adherence to drinking water regulations compared to public water supplies and publicly-sourced and privately-sourced Group Water Schemes.

In 2018, commercial businesses (e.g. hotel, B&B, pub), or public buildings (e.g. schools, crèches, campsites) that obtain their water from a well or other private source are at greater risk of being contaminated than public water supplies45. More than 60 of these private supplies were found to be contaminated with human or animal waste at least once during 2018. Cases of VTEC infection – which can be contracted due to consuming water contaminated by animal waste – has continued to rise with over 1,000 reported cases in 2018. Ireland continues to have the highest incidence of VTEC infection in Europe.

Recent research by NUI Galway46 suggests that current monitoring programmes need to be expanded to include other substances and parameters. Of 75 tested samples from recreational bathing areas (seawater, lakes and rivers), 65% were positive for genetic markers for pathogenic E.coli (STEC) that can cause severe intestinal infection and potentially renal failure. River samples recorded the highest

45 http://erc.epa.ie/safer/resourcelisting.jsp?oID=10206&username=EPA%20Drinki ng%20Water

46 https://www.nuigalway.ie/about-us/news-and-events/news-archive/2020/april/study-detects-presence-of-disease.

causing-ecoli-in-recreational-waters-including-in-bathing-waters-rated-excellent-und-1.html

prevalence of 93% of samples (14/15 samples) contaminated with STEC at. All bathing waters monitored in this NUI Galway study had been identified as being of high or good ecological status. The research highlighted the ‘limitations of only assessing the total number of E.coli as an indicator of water quality without taking into consideration the pathogenicity of some variants’.

Manure management to reduce pathogen populations: Pathogens are most likely to be transported to water through surface runoff and erosion or by direct animal access to surface water47. Streams and lakes used for drinking water supply and recreational purposes provide the greatest opportunity for transporting these pathogens to humans. Pathogens usually do not move through soil profiles and reach groundwater because of the filtering capabilities of soil. Exceptions to this occur adjacent to poorly maintained well casings.

Most human pathogens do not multiply outside their host but can survive from a few days to several months depending upon environmental factors including temperature, moisture, pH, and oxygen. Composting livestock manure for several weeks prior to application to the land significantly reduces the risk of exposure to these pathogens.

Chemicals

Good chemical status means that no concentrations of priority substances exceed the relevant Environmental Quality Standards (EQS) established in the Environmental Quality Standards Directive 2008/105/EC. EQS aim to protect the most sensitive species from direct toxicity, including predators and humans via secondary poisoning. Under the WFD, losses, discharges and emissions to water of a particularly harmful subset of these, priority hazardous substances, should be completely phased out within 20 years, and uses of these substances have been significantly restricted.

Chemical pollutants are or have been emitted into water bodies through a range of pathways and from a variety of sources, including industry, agriculture, transport, mining and waste disposal, as well as from homes. Significant levels of some priority substances have built up from historical use and this legacy pollution may persist in water bodies long after pollutant discharges and inputs have ended.

Of the thousands of chemicals in daily use, relatively few are reported under the WFD48. There is a gap in knowledge at European level over whether any of these other substances present a significant risk to or via the aquatic environment, either individually or in combination with other substances. In addition, information on the sources and emissions of many pollutants remains incomplete, limiting the scope for identifying and targeting appropriate measures.

The main pressures leading to failure to achieve good chemical status are atmospheric deposition and discharges from urban wastewater treatment plants. Reducing hazardous substances in water requires implementation of the current legislation but also adopting more sustainable production and use of chemicals47.

47 https://water.unl.edu/understanding-water-quality-issues-pathogens-and-organic-matter

48 European Waters Assessment of status and pressures 2018 https://www.eea.europa.eu/themes/water/european.

waters/water-quality-and-water-assessment/water-assessments/pressures-and-impacts-of-water-bodies

The National Aquatic Environmental Chemistry Group (NAECG) are reviewing hazardous chemicals in the aquatic environment and are identifying new monitoring programmes for new compounds and a more strategic approach to the management of hazardous chemicals.

Chemicals such as pesticides are impacting our aquatic plants and wildlife and are contaminating our drinking water supplies. The EU Biodiversity Strategy has identified that pesticide use will be reduced by 50% by 2030. The herbicide MCPA, used to kill weeds and rushes, has been detected by the EPA in over half of all rivers monitored. In 2018, MCPA was responsible for three quarters of drinking water quality standard failures due to pesticides. As it is very difficult to remove MCPA from water it is a priority that its use is reduced or eliminated.

The National Pesticides in Drinking Water Action Group are a collaborative group set up to address the issue of Pesticides in Drinking water however more widespread targets are needed to achieve the Biodiversity Strategy goal of a minimum 50% reduction in use by 2030.

In addition to the training and registration of professional users of pesticides, guidance is needed for retailers including more detailed labelling to address use and storage requirements.

A public information and awareness campaign is recommended for the wider public on the labelling, identification and impact of hazardous chemicals to the aquatic environment, water quality and biodiversity.

Invasive Alien Species

Invasive Alien Species (IAS) are one of the top five threats to the natural environment worldwide. IAS are species that have moved outside of their natural range and negatively affect native biodiversity, ecosystem services and public health, through predation, competition or by transmitting disease49.

A project funded by the EPA Research Programme50, identified 40 species likely to arrive, establish, spread and cause impacts to biodiversity on the island of Ireland and of these top 40 species, 18 were freshwater species, 7 of which were placed in the top 10 for impact (Table 2). Pathways of introduction were also identified to inform on biosecurity strategies. The recommended biosecurity actions include effective risk assessment, improved detection, recording and inspection at ports and airports, full implementation of the Habitats Regulation in the ROI and the Wildlife and Natural Environment Act (Northern Ireland), to include management of trade including internet trade.

49 https://www.researchgate.net/project/Prevention-control-and-eradication-of-invasive.

species/update/5e99c7ef4f9a520001e07f67

50 https://www.researchgate.net/publication/298559361

Table 2: Horizon Scanning for Invasive Alien Species in Ireland31

A recent UK House of Commons Environmental Audit estimated the cost of INNS poses to the British economy at £1.3 billion a year; £125 million in Wales and £250 million in Scotland51. The report also stated that it is immeasurably more cost effective to prevent the establishment of INNS through biosecurity measures such as closing arrival pathways than through eradication programmes once they become established38. Public awareness campaigns are key to prevent the introduction of INNS and the Environment Committee propose training approximately 2% of the UK population as biosecurity volunteers (1.3million people) to help eradicate priority invasive species51.

Codes of practice for pathways and INNS, similar to Check-Clean-Dry, need to be developed and promoted, and more training and citizen science events are needed to reach all ages and sectors in society. The UK recommendations include that emergency funds are made available to tackle and control pathogens once they are identified.

51House of Commons Environment Audit Committee Invasive Species

https://publications.parliament.uk/pa/cm201919/cmselect/cmenvaud/88/88.pdf

Microplastics

Plastic production has increased exponentially since the early 1950s and reached 322 million tonnes in 2015, this figure does not include synthetic fibres which accounted for an additional 61 million tonnes in 201552 It is expected that production of plastics will continue to increase in the foreseeable future and production levels are likely to double by 202553. Inadequate management of plastic waste has led to increased contamination of freshwater, estuarine and marine environments.

Microplastics are usually defined as plastic items which measure less than 5 mm in their longest dimension, this definition includes also nanoplastics which are particles less than 100 nanometres (nm) in their longest dimension. Microplastics are largely resistant to biological degradation and may also act as vectors for bacteria and viruses as well as persistent, bio-accumulative and toxic contaminants (PBTs) from the environment.

Microplastics can be directly emitted by land-based sources to the aquatic environment but may also result from poor waste management or the degradation of larger plastic waste (littering). Directly emitted microplastics can be primary microplastics, such as from personal care products (also called

‘microbeads’), industrial abrasives, paints and coatings and detergents, or secondary microplastics

originating mainly from tyres, road markings, textiles and building paints, and/or pre-production pellets unintentionally emitted through accidental spills. On the European scale, a UK based research consultancy, Eunomia, estimates direct secondary microplastics emissions from land-based sources to the environment at about one million tonnes per year, with about half of it stemming from automotive tyre abrasion. It is also estimated that 28% of all microplastics released from products may end up in surface waters54.

A University College Cork research project estimates that the island of Ireland emits 5,700 kg of microplastics per year through industry, landfill, waste water, domestic sources and road surfaces. These microplastics often make their way into our waters, entering the food chain and also our drinking water55.

With regard to the impact of microplastics on freshwater ecology, some studies already indicate their detrimental impact on fish productivity and physiological processes for fisheries and aquaculture.

Microplastics contain a mixture of chemicals added during manufacture and efficiently sorb (adsorb or absorb) persistent, bioaccumulative and toxic contaminants (PBTs) from the environment. The ingestion of microplastics by aquatic organisms and the accumulation of PBTs have been central to the perceived hazard and risk of microplastics in the marine environment.

52 Microplastics and the water sector Briefing Note EurEau http://www.eureau.org/resources/briefing-notes

53Food and Agriculture Organisation of the United Nations Microplastics in fisheries and agriculture Technical paper 615

http://www.fao.org/3/a-i7677e.pdf

54 Investigating options for reducing the release to the aquatic environment of microplastics emitted by products

https://www.eunomia.co.uk/case_study/measuring-impacts-of-microplastics/

55 UCC Project Impacts of microplastics on the freshwater environment https://ecotoxicology.ucc.ie/microplastics/

Microplastics are widespread in the air we breathe, in some of the food we eat (shellfish, honey, salt), and liquids we drink52. The potential impact of microplastics on public health and ecosystems is a growing public concern and has been high on the agenda of decision makers for some time52. With growing global use of (micro-)plastics, their release to the environment is expected to increase and microplastic contamination of aquatic environments will continue to increase for the foreseeable future.

Organic Matter

The term “natural organic matter” (NOM) refers to a wide spectrum of carbon-based compounds that result from natural processes in the environment. It originates from living and dead plants, animals and microorganisms and from the degradation products of these sources56. The presence of NOM causes many problems in drinking water treatment processes, in addition to aesthetic problems such as colour, taste and odour, it contributes to the fouling of membranes and serves as a precursor for the formation of disinfectant by-products (DBPs).

NOM rich in aromatic structures has been found to be highly reactive with chlorine, with a higher potential to form DBPs35. Large molecular hydrophobic humic substances are enriched with aromatic structures and are easily removed by conventional drinking water treatment consisting of coagulation, flocculation, clarification (CFC) and filtration.

However, non-aromatic NOM can also form trihalomethanes (THMs). Low molecular weight hydrophilic and less aromatic NOM is more problematic to remove and is a major contributor of easily biodegradable organic carbon, which promotes microbiological regrowth in the distribution system. An understanding of the behaviour of different fractions or constituents of NOM present in water is crucial to understanding their fate and impact during water treatment and in water distribution systems. Therefore, accurate characterisation of NOM in raw water and along the treatment process would be an important basis for the selection of water treatment processes, monitoring of the performance of different treatment steps, and assessing distribution system water quality.

Successive Environmental Protection Agency (EPA) reports57 have shown that Ireland has an unacceptably high number of drinking water supplies exceeding the parametric value of 100 µg L–1 for average total trihalomethanes (TTHMs). Guidance issued by the HSE58 states that THMs ‘are possibly carcinogenic to humans’. In 2010, Ireland had the highest non-compliance with respect to TTHMs in drinking water across the 27 EU Member States (Figure 6).

56 O’Driscoll, C. et al. An assessment of Natural Organic Matter and Ptaquiloside in Irish waters and references within

http://www.epa.ie/researchandeducation/research/researchpublications/researchreports/EPA%20RR%20231_web.pdf

57 Drinking water quality in public supplies 2018

http://www.epa.ie/pubs/reports/water/drinking/EPA%20DW%20Public%20Supplies_web.pdf

58 Health Service Executive (2016). Trihalomethanes in drinking water. Information for consumers.

https://www.hse.ie/eng/health/hl/water/drinkingwater/information-for-consumers-trihalomethanes-in-drinking.

water.pdf

Figure 6: Non-compliance for THM exceedances in EU Member States reporting ≥0.1% compliance for 2010. Large water supply zones refer to zones supplying more than 5000 people and small supply zones to those supplying fewer than 500045.

On 14 May 2020, the European Commission provided a reasoned opinion to Ireland regarding its failure to fulfil its obligations under the Drinking Water Directive with regards to Trihalomethane (THM) levels in drinking water supply zones and schemes59. This follows on from an infringement case brought against Ireland by the EU in August 2018 for persistent exceedance of THMs in drinking water.

The majority of THM failures identified by the EPA were caused by either the absence of adequate treatment to remove organic matter or the presence of treatment that is incapable of removing high levels of organic matter 60.

Increases in NOM from peaty catchments have been attributed to global warming35 and changes in land management practices, such as peat harvesting, peatland forestry and agriculture can change aquatic NOM quantity and character61.

With Ireland struggling to adhere to the Drinking Water Directive as a result of its persistent high levels of THMs in its drinking waters over the past 20 years, there are significant implications of future climate change on the potential for THM formation in Irish drinking water supplies.

Water Level and Flow

Flow levels in are influenced by climatic factors: precipitation, temperature, evapotranspiration; by non-climatic factors such as land use, urbanisation, water withdrawals, industry; and catchment

59 https://ec.europa.eu/commission/presscorner/detail/en/inf_20_859

60 EPA Drinking water repot for public supplies

http://www.epa.ie/pubs/reports/water/drinking/2015%20DW%20Report%20Public%20Supplies_web.pdf

61 Jones et al., 2001. Global Biogeochemical Cycles 1: p863-87

storage capacity (geology and soil type). Climate change can negatively impact on freshwater ecosystems by changing streamflow and water quality.

Mean annual temperatures in Ireland have increased by 0.7˚C over the past century (Figure 7)62. Winter rainfall is projected to increases by 10% with summer reductions of 12%-17% with the most extreme reductions in the south and east63. Changes in the frequency of extreme events is also to be expected. Hydrological modelling show that catchments dependent on groundwater are most vulnerable to longer soil moisture deficits; slower groundwater recharge; and increased risk of drought when a dry summer follows a dry winter. In catchments where surface run-off is more dominant changes in summer flow levels are more pronounced. Significant changes in stream flows are also projected with up to 20% increases in springtime and significant reductions in summer and autumn63.

In terms of high flows, the 10-year flood is expected to become a 3-7 year event63. Increases in the magnitude and frequency of flood events are likely to impact on water quality. Flooding increases sedimentation and suspended loads that are problematic for aquatic life and can overwhelm foul sewer systems and the effective functioning of water treatment plants adding suspended solids and nutrient loads to rivers.

Figure 7: Annual mean surface air temperature (1900-2011)62

62 Dwyer, N. (2012). The status of Ireland’s Climate, 2012. Report for the Environmental Protection Agency of Ireland, Wexford, Ireland.

http://www.epa.ie/pubs/reports/research/climate/CCRP26%20-%20Status%20of%20Ireland%27s%20Climate%202012.pdf

63 Sweeney, J et al. 2001 Climate Change, Refining the impacts for Ireland

Climate change is projected to reduce raw water quality, posing risks to drinking water quality even with conventional treatment64. The sources of the risks are increased temperature, increases in sediment, nutrient and pollutant loadings due to heavy rainfall, reduced dilution of pollutants during droughts, and disruption of treatment facilities during floods64. Anthropogenic impacts such as increased abstractions and wastewater discharges also put further stress on the system particularly in low flow conditions.

Predicted changes in flow levels and regional variations in water availability and demand poses challenges for the management of water resources in particular matching supply and demand across the island. The Greater Dublin area is the most susceptible to drier conditions in the future yet has the greatest projected anthropogenic demands owing to projected population growth.

Drought management is an essential element of water resource policy and strategies. Drought management plans, based on the characterisation of possible droughts in a catchment, their effect, and possible mitigation measures, should be prepared on a river catchment scale and before emergency schemes need to be applied. Drought management plans, by promoting sustainable water use, are closely linked with the WFD objectives.

Land management and land use planning are essential to the management of water resources in water-scarce areas. Important wetlands, which help to store water, have been degraded or destroyed. One priority should be to retain rainwater where it falls, enabling water infiltration through the re.establishment of wetlands and the increased recharge of aquifers.

Temperature

Rising water temperatures will affect aquatic habitats and cause species migrations. Cold water fish species such as salmon and trout are particularly susceptible to increasing water temperatures. Water temperature is an important factor in determining whether a body of water is also acceptable for human consumption and use:

•

The temperature in water governs the kinds and types of aquatic life that live in it.

•

Temperature influences the rate of chemical and biological reactions.

•

It affects the dissolved oxygen levels in water, photosynthesis of aquatic plants, metabolic rates of aquatic organisms, and the sensitivity of these organisms to pollution, parasites, and disease.

Temperature and drinking water

The temperature of drinking water is largely determined by the raw water source or by the depth of the intake. Rates of chemical reaction increase with increasing temperature. The relative

64 Jiminez Cisneros, B.E., Oki, T.E., Arnell, N.W., Benito, G., Cogley, P., Doll, P., Jiang, T. and Mwakalila, S.S. (2014). Freshwater resources. In: Climate Change 2014: Impacts, Adaptation and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

http://www.ipcc.ch/site/assets/uploads/2018/02/WGIIAR5-Chap3_FINAL.pdf

concentrations of reactants and products in chemical equilibria can also change with temperature65. Increasing water temperature will also increase the vapour pressure of trace volatiles in drinking water and can lead to increased odour which can be unpalatable for consumers. Micro-fungi can grow inside plumbing systems of buildings, leading to musty or mouldy tastes if the temperature rises above 16oC. Temperature therefore can affect every aspect of the treatment and delivery of potable water.

The viscosity of water decreases with increasing temperature so the rate of sedimentation increases. Warm water stratifies over cooler water such that a small increase in temperature <1oC in raw water can decrease the efficiency of the flocculation-sedimentation process in treatment. Studies have also found that the rate of chloroform formation in raw water treated with chlorine doubled at higher temperatures and the rate of trihalomethane formation increases at higher temperatures.

Temperature and water quality

Climate change impacts how much water is available in the water cycle to refill lakes and rivers. Increased temperature increases evaporation of surface water and a warmer atmosphere can hold more moisture. This can cause lower water levels in some areas in summertime and enhanced precipitation during warmer winters and projections for Ireland are for warmer, dryer summers and warmer wetter winters66.

Temperature is a critical water quality parameter as it regulates the dissolved oxygen concentrations in aquatic environments. Organisms within ecosystems have preferred temperature regimes that change as a function of season, organism age and life cycle and other environmental factors67.

Higher water temperatures can impact on metabolic and chemical reactions. The physical features of a stream impacts on water temperature such as vegetation cover and physical aspects like channel width and land use (such as urban runoff) with increasing water temperature most impactful during low flow conditions.

Temperature impacts on lakes and reservoirs with lower dissolved oxygen coupled with nutrient concentrations often leading to algal blooms. In summer the top of the lake becomes warmer than lower layers, leading to thermal stratification that can result in anoxic conditions in the bottom layers. As seasons change, when the surface water cools and becomes denser, it sinks placing stress on biological communities within the water body.

Between 1973 and 2014, the annual minimum lake surface temperature across eight European Lakes (including Lough Feeagh, County Mayo) has increased at an average rate of +0.35 ˚C per decade68. The

65 https://www.safewater.org/fact-sheets-1/2018/8/15/water-temperature-fact-sheet

66 O’Dwyer et. al., 2017. The Development of Irish Climate Information Platform ICIP Phase 3 2015-2017 EPA Report 258

http://www.epa.ie/pubs/reports/research/climate/Research_Report_258.pdf

67 https://www.water-research.net/index.php/stream-water-quality-importance-of-temperature

68 Woolway, R.I. et al. (2019). Substantial increase in minimum lake surface temperatures under climate change. Climatic Change. https://doi.org/10.1007/s10584-019-02465-y

drought period between May-July 2018 was bisected by Storm Hector in late June 2018. The storm quickly and abruptly altered the temperature depth profile of Lough Feeagh, before the lake restabilised following the storm. The changes in lake physics as a result of these two extreme climate events had a significant impact on the lake ecology, highlighting the importance of temperature in aquatic systems and the implications of future climate change69.

69 Caldero-Pascual, M. (2020). Effects of consecutive extreme weather events on a temperate dystrophic lake: A detailed insight into physical, chemical and biological response. Water 12: 1411.

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wastewater treatment

Table of Contents

• Introduction & Top Questions

• Historical background

• Sources of water pollution

• Sewage characteristics

• Sewerage systems

• Wastewater treatment and disposal

• Sludge treatment and disposal

• Emerging technologies

References & Edit HistoryQuick Facts & Related Topics

Images & Videos

Related Questions

• What are the common pollutants present in wastewater?

• How is wastewater processed at a sewage treatment facility?

• Why is wastewater resource recovery important?

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wastewater treatment

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Also known as: sewage treatment

Written by

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Jerry A. NathansonSee All

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Last Updated: Nov 20, 2023 • Article History

Cloaca Maxima

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sewage treatment

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Nov. 20, 2023, 3:20 AM ET (AP)

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Top Questions

What is wastewater?

How is wastewater generated?

What are the common pollutants present in wastewater?

How is wastewater processed at a sewage treatment facility?

Why is wastewater resource recovery important?

Discover how wastewater is transformed back into drinking water by undergoing various processes in the wastewater treatment plants

Learn about the steps in the wastewater treatment process.

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Wastewater treatment, the removal of impurities from wastewater, or sewage, before it reaches aquifers or natural bodies of water such as rivers, lakes, estuaries, and oceans. Since pure water is not found in nature (i.e., outside chemical laboratories), any distinction between clean water and polluted water depends on the type and concentration of impurities found in the water as well as on its intended use. In broad terms, water is said to be polluted when it contains enough impurities to make it unfit for a particular use, such as drinking, swimming, or fishing. Although water quality is affected by natural conditions, the word pollution usually implies human activity as the source of contamination. Water pollution, therefore, is caused primarily by the drainage of contaminated wastewater into surface water or groundwater, and wastewater treatment is a major element of water pollution control.

Historical background

Direct discharge of sewage

Many ancient cities had drainage systems, but they were primarily intended to carry rainwater away from roofs and pavements. A notable example is the drainage system of ancient Rome. It included many surface conduits that were connected to a large vaulted channel called the Cloaca Maxima (“Great Sewer”), which carried drainage water to the Tiber River. Built of stone and on a grand scale, the Cloaca Maxima is one of the oldest existing monuments of Roman engineering.

There was little progress in urban drainage or sewerage during the Middle Ages. Privy vaults and cesspools were used, but most wastes were simply dumped into gutters to be flushed through the drains by floods. Toilets (water closets) were installed in houses in the early 19th century, but they were usually connected to cesspools, not to sewers. In densely populated areas, local conditions soon became intolerable because the cesspools were seldom emptied and frequently overflowed. The threat to public health became apparent. In England in the middle of the 19th century, outbreaks of cholera were traced directly to well-water supplies contaminated with human waste from privy vaults and cesspools. It soon became necessary for all water closets in the larger towns to be connected directly to the storm sewers. This transferred sewage from the ground near houses to nearby bodies of water. Thus, a new problem emerged: surface water pollution.

Developments in sewage treatment

It used to be said that “the solution to pollution is dilution.” When small amounts of sewage are discharged into a flowing body of water, a natural process of stream self-purification occurs. Densely populated communities generate such large quantities of sewage, however, that dilution alone does not prevent pollution. This makes it necessary to treat or purify wastewater to some degree before disposal.

The construction of centralized sewage treatment plants began in the late 19th and early 20th centuries, principally in the United Kingdom and the United States. Instead of discharging sewage directly into a nearby body of water, it was first passed through a combination of physical, biological, and chemical processes that removed some or most of the pollutants. Also beginning in the 1900s, new sewage-collection systems were designed to separate storm water from domestic wastewater, so that treatment plants did not become overloaded during periods of wet weather.

After the middle of the 20th century, increasing public concern for environmental quality led to broader and more stringent regulation of wastewater disposal practices. Higher levels of treatment were required. For example, pretreatment of industrial wastewater, with the aim of preventing toxic chemicals from interfering with the biological processes used at sewage treatment plants, often became a necessity. In fact, wastewater treatment technology advanced to the point where it became possible to remove virtually all pollutants from sewage. This was so expensive, however, that such high levels of treatment were not usually justified.

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Wastewater treatment plants became large, complex facilities that required considerable amounts of energy for their operation. After the rise of oil prices in the 1970s, concern for energy conservation became a more important factor in the design of new pollution control systems. Consequently, land disposal and subsurface disposal of sewage began to receive increased attention where feasible. Such “low-tech” pollution control methods not only might help to conserve energy but also might serve to recycle nutrients and replenish groundwater supplies.

Sources of water pollution

Water pollutants may originate from point sources or from dispersed sources. A point-source pollutant is one that reaches water from a single pipeline or channel, such as a sewage discharge or outfall pipe. Dispersed sources are broad, unconfined areas from which pollutants enter a body of water. Surface runoff from farms, for example, is a dispersed source of pollution, carrying animal wastes, fertilizers, pesticides, and silt into nearby streams. Urban storm water drainage, which may carry sand and other gritty materials, petroleum residues from automobiles, and road deicing chemicals, is also considered a dispersed source because of the many locations at which it enters local streams or lakes. Point-source pollutants are easier to control than dispersed-source pollutants, since they flow to a single location where treatment processes can remove them from the water. Such control is not usually possible over pollutants from dispersed sources, which cause a large part of the overall water pollution problem. Dispersed-source water pollution is best reduced by enforcing proper land-use plans and development standards.

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General types of water pollutants include pathogenic organisms, oxygen-demanding wastes, plant nutrients, synthetic organic chemicals, inorganic chemicals, microplastics, sediments, radioactive substances, oil, and heat. Sewage is the primary source of the first three types. Farms and industrial facilities are also sources of some of them. Sediment from eroded topsoil is considered a pollutant because it can damage aquatic ecosystems, and heat (particularly from power-plant cooling water) is considered a pollutant because of the adverse effect it has on dissolved oxygen levels and aquatic life in rivers and lakes.

Sewage characteristics

Types of sewage

There are three types of wastewater, or sewage: domestic sewage, industrial sewage, and storm sewage. Domestic sewage carries used water from houses and apartments; it is also called sanitary sewage. Industrial sewage is used water from manufacturing or chemical processes. Storm sewage, or storm water, is runoff from precipitation that is collected in a system of pipes or open channels.

Domestic sewage is slightly more than 99.9 percent water by weight. The rest, less than 0.1 percent, contains a wide variety of dissolved and suspended impurities. Although amounting to a very small fraction of the sewage by weight, the nature of these impurities and the large volumes of sewage in which they are carried make disposal of domestic wastewater a significant technical problem. The principal impurities are putrescible organic materials and plant nutrients, but domestic sewage is also very likely to contain disease-causing microbes. Industrial wastewater usually contains specific and readily identifiable chemical compounds, depending on the nature of the industrial process. Storm sewage carries organic materials, suspended and dissolved solids, and other substances picked up as it travels over the ground.

Principal pollutants

Organic material

The amount of putrescible organic material in sewage is indicated by the biochemical oxygen demand, or BOD; the more organic material there is in the sewage, the higher the BOD, which is the amount of oxygen required by microorganisms to decompose the organic substances in sewage. It is among the most important parameters for the design and operation of sewage treatment plants. Industrial sewage may have BOD levels many times that of domestic sewage. The BOD of storm sewage is of particular concern when it is mixed with domestic sewage in combined sewerage systems (see below).

Dissolved oxygen is an important water quality factor for lakes and rivers. The higher the concentration of dissolved oxygen, the better the water quality. When sewage enters a lake or stream, decomposition of the organic materials begins. Oxygen is consumed as microorganisms use it in their metabolism. This can quickly deplete the available oxygen in the water. When the dissolved oxygen levels drop too low, trout and other aquatic species soon perish. In fact, if the oxygen level drops to zero, the water will become septic. Decomposition of organic compounds without oxygen causes the undesirable odours usually associated with septic or putrid conditions.

Suspended solids

Another important characteristic of sewage is suspended solids. The volume of sludge produced in a treatment plant is directly related to the total suspended solids present in the sewage. Industrial and storm sewage may contain higher concentrations of suspended solids than domestic sewage. The extent to which a treatment plant removes suspended solids, as well as BOD, determines the efficiency of the treatment process.

Plant nutrients

Domestic sewage contains compounds of nitrogen and phosphorus, two elements that are basic nutrients essential for the growth of plants. In lakes, excessive amounts of nitrates and phosphates can cause the rapid growth of algae. Algal blooms, often caused by sewage discharges, accelerate the natural aging of lakes in a process called eutrophication.

Microbes

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Domestic sewage contains many millions of microorganisms per gallon. Most are coliform bacteria from the human intestinal tract, and domestic sewage is also likely to carry other microbes. Coliforms are used as indicators of sewage pollution. A high coliform count usually indicates recent sewage pollution.

Sewerage systems

A sewerage system, or wastewater collection system, is a network of pipes, pumping stations, and appurtenances that convey sewage from its points of origin to a point of treatment and disposal.

Combined systems

Systems that carry a mixture of both domestic sewage and storm sewage are called combined sewers. Combined sewers typically consist of large-diameter pipes or tunnels, because of the large volumes of storm water that must be carried during wet-weather periods. They are very common in older cities but are no longer designed and built as part of new sewerage facilities. Because wastewater treatment plants cannot handle large volumes of storm water, sewage must bypass the treatment plants during wet weather and be discharged directly into the receiving water. These combined sewer overflows, containing untreated domestic sewage, cause recurring water pollution problems and are very troublesome sources of pollution.

In some large cities the combined sewer overflow problem has been reduced by diverting the first flush of combined sewage into a large basin or underground tunnel. After temporary storage, it can be treated by settling and disinfection before being discharged into a receiving body of water, or it can be treated in a nearby wastewater treatment plant at a rate that will not overload the facility. Another method for controlling combined sewage involves the use of swirl concentrators. These direct sewage through cylindrically shaped devices that create a vortex, or whirlpool, effect. The vortex helps concentrate impurities in a much smaller volume of water for treatment.

Separate systems

New wastewater collection facilities are designed as separate systems, carrying either domestic sewage or storm sewage but not both. Storm sewers usually carry surface runoff to a point of disposal in a stream or river. Small detention basins may be built as part of the system, storing storm water temporarily and reducing the magnitude of the peak flow rate. Sanitary sewers, on the other hand, carry domestic wastewater to a sewage treatment plant. Pretreated industrial wastewater may be allowed into municipal sanitary sewerage systems, but storm water is excluded.

Storm sewers are usually built with sections of reinforced concrete pipe. Corrugated metal pipes may be used in some cases. Storm water inlets or catch basins are located at suitable intervals in a street right-of-way or in easements across private property. The pipelines are usually located to allow downhill gravity flow to a nearby stream or to a detention basin. Storm water pumping stations are avoided, if possible, because of the very large pump capacities that would be needed to handle the intermittent flows.

A sanitary sewerage system includes laterals, submains, and interceptors. Except for individual house connections, laterals are the smallest sewers in the network. They usually are not less than 200 mm (8 inches) in diameter and carry sewage by gravity into larger submains, or collector sewers. The collector sewers tie in to a main interceptor, or trunk line, which carries the sewage to a treatment plant. Interceptors are usually built with precast sections of reinforced concrete pipe, up to 5 metres (15 feet) in diameter. Other materials used for sanitary sewers include vitrified clay, asbestos cement, plastic, steel, or ductile iron. The use of plastic for laterals is increasing because of its lightness and ease of installation. Iron and steel pipes are used for force mains or in pumping stations. Force mains are pipelines that carry sewage under pressure when it must be pumped.

Alternative systems

Sometimes the cost of conventional gravity sewers can be prohibitively high because of low population densities or site conditions such as a high water table or bedrock. Three alternative wastewater collection systems that may be used under these circumstances include small-diameter gravity sewers, pressure sewers, and vacuum sewers.

In small-diameter gravity systems, septic tanks are first used to remove settleable and floating solids from the wastewater from each house before it flows into a network of collector mains (typically 100 mm, or 4 inches, in diameter); these systems are most suitable for small rural communities. Because they do not carry grease, grit and sewage solids, the pipes can be of smaller diameter and placed at reduced slopes or gradients to minimize trench excavation costs. Pressure sewers are best used in flat areas or where expensive rock excavation would be required. Grinder pumps discharge wastewater from each home into the main pressure sewer, which can follow the slope of the ground. In a vacuum sewerage system, sewage from one or more buildings flows by gravity into a sump or tank from which it is pulled out by vacuum pumps located at a central vacuum station and then flows into a collection tank. From the vacuum collection tank the sewage is pumped to a treatment plant.

Pumps

Pumping stations are built when sewage must be raised from a low point to a point of higher elevation or where the topography prevents downhill gravity flow. Special nonclogging pumps are available to handle raw sewage. They are installed in structures called lift stations. There are two basic types of lift stations: dry well and wet well. A wet-well installation has only one chamber or tank to receive and hold the sewage until it is pumped out. Specially designed submersible pumps and motors can be located at the bottom of the chamber, completely below the water level. Dry-well installations have two separate chambers, one to receive the wastewater and one to enclose and protect the pumps and controls. The protective dry chamber allows easy access for inspection and maintenance. All sewage lift stations, whether of the wet-well or dry-well type, should include at least two pumps. One pump can operate while the other is removed for repair.

Flow rates

There is a wide variation in sewage flow rates over the course of a day. A sewerage system must accommodate this variation. In most cities domestic sewage flow rates are highest in the morning and evening hours. They are lowest during the middle of the night. Flow quantities depend upon population density, water consumption, and the extent of commercial or industrial activity in the community. The average sewage flow rate is usually about the same as the average water use in the community. In a lateral sewer, short-term peak flow rates can be roughly four times the average flow rate. In a trunk sewer, peak flow rates may be two-and-a-half times the average.

Although sewage flows depend upon residential, commercial, and industrial connections, sewage flow rates potentially can become higher as a result of inflows and infiltration (I&I) into the sanitary sewer system. Inflows correspond to storm water entering sewers from inappropriate connections, such as roof drains, storm drains, downspouts and sump pumps. High amounts of rainwater runoff can reach the sewer system during precipitation and stormflow events or during seasonal spring flooding of rivers inundated with melting ice. Infiltration refers to the groundwater entering sewers via defective or broken pipes. In both these cases, downstream utilities and treatment plants may experience flows higher than anticipated and can become hydraulically overloaded. During such overloads, utilities may ask residents connected to the system to refrain from using dishwashers and washing machines and may even limit toilet flushing and the use of showers in an attempt to lessen the strain. Such I&I issues can be especially severe in old and aging water infrastructures.

Wastewater treatment and disposal

The size and capacity of wastewater treatment systems are determined by the estimated volume of sewage generated from residences, businesses, and industries connected to sewer systems as well as the anticipated inflows and infiltration (I&I). The selection of specific on-lot, clustered, or centralized treatment plant configurations depends upon factors such as the number of customers being served, the geographical scenario, site constraints, sewer connections, average and peak flows, influent wastewater characteristics, regulatory effluent limits, technological feasibility, energy consumption, and the operations and maintenance costs involved.

The predominant method of wastewater disposal in large cities and towns is discharge into a body of surface water. Suburban and rural areas rely more on subsurface disposal. In either case, wastewater must be purified or treated to some degree in order to protect both public health and water quality. Suspended particulates and biodegradable organics must be removed to varying extents. Pathogenic bacteria must be destroyed. It may also be necessary to remove nitrates and phosphates (plant nutrients) and to neutralize or remove industrial wastes and toxic chemicals.

The degree to which wastewater must be treated varies, depending on local environmental conditions and governmental standards. Two pertinent types of standards are stream standards and effluent standards. Stream standards, designed to prevent the deterioration of existing water quality, set limits on the amounts of specific pollutants allowed in streams, rivers, and lakes. The limits depend on a classification of the “maximum beneficial use” of the water. Water quality parameters that are regulated by stream standards include dissolved oxygen, coliforms, turbidity, acidity, and toxic substances. Effluent standards, on the other hand, pertain directly to the quality of the treated wastewater discharged from a sewage treatment plant. The factors controlled under these standards usually include biochemical oxygen demand (BOD), suspended solids, acidity, and coliforms.

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There are three levels of wastewater treatment: primary, secondary, and tertiary (or advanced). Primary treatment removes about 60 percent of total suspended solids and about 35 percent of BOD; dissolved impurities are not removed. It is usually used as a first step before secondary treatment. Secondary treatment removes more than 85 percent of both suspended solids and BOD. A minimum level of secondary treatment is usually required in the United States and other developed countries. When more than 85 percent of total solids and BOD must be removed, or when dissolved nitrate and phosphate levels must be reduced, tertiary treatment methods are used. Tertiary processes can remove more than 99 percent of all the impurities from sewage, producing an effluent of almost drinking-water quality. Tertiary treatment can be very expensive, often doubling the cost of secondary treatment. It is used only under special circumstances.

For all levels of wastewater treatment, the last step prior to discharge of the sewage effluent into a body of surface water is disinfection, which destroys any remaining pathogens in the effluent and protects public health. Disinfection is usually accomplished by mixing the effluent with chlorine gas or with liquid solutions of hypochlorite chemicals in a contact tank for at least 15 minutes. Because chlorine residuals in the effluent may have adverse effects on aquatic life, an additional chemical may be added to dechlorinate the effluent. Ultraviolet radiation, which can disinfect without leaving any residual in the effluent, is becoming more competitive with chlorine as a wastewater disinfectant.

Primary treatment

activated sludge process

Primary and secondary treatment of sewage, using the activated sludge process.(more)

Primary treatment removes material that will either float or readily settle out by gravity. It includes the physical processes of screening, comminution, grit removal, and sedimentation. Screens are made of long, closely spaced, narrow metal bars. They block floating debris such as wood, rags, and other bulky objects that could clog pipes or pumps. In modern plants the screens are cleaned mechanically, and the material is promptly disposed of by burial on the plant grounds. A comminutor may be used to grind and shred debris that passes through the screens. The shredded material is removed later by sedimentation or flotation processes.

Grit chambers are long narrow tanks that are designed to slow down the flow so that solids such as sand, coffee grounds, and eggshells will settle out of the water. Grit causes excessive wear and tear on pumps and other plant equipment. Its removal is particularly important in cities with combined sewer systems, which carry a good deal of silt, sand, and gravel that wash off streets or land during a storm.

Suspended solids that pass through screens and grit chambers are removed from the sewage in sedimentation tanks. These tanks, also called primary clarifiers, provide about two hours of detention time for gravity settling to take place. As the sewage flows through them slowly, the solids gradually sink to the bottom. The settled solids—known as raw or primary sludge—are moved along the tank bottom by mechanical scrapers. Sludge is collected in a hopper, where it is pumped out for removal. Mechanical surface-skimming devices remove grease and other floating materials.

Secondary treatment

Secondary treatment removes the soluble organic matter that escapes primary treatment. It also removes more of the suspended solids. Removal is usually accomplished by biological processes in which microbes consume the organic impurities as food, converting them into carbon dioxide, water, and energy for their own growth and reproduction. The sewage treatment plant provides a suitable environment, albeit of steel and concrete, for this natural biological process. Removal of soluble organic matter at the treatment plant helps to protect the dissolved oxygen balance of a receiving stream, river, or lake.

There are three basic biological treatment methods: the trickling filter, the activated sludge process, and the oxidation pond. A fourth, less common method is the rotating biological contacter.

Trickling filter

A trickling filter is simply a tank filled with a deep bed of stones. Settled sewage is sprayed continuously over the top of the stones and trickles to the bottom, where it is collected for further treatment. As the wastewater trickles down, bacteria gather and multiply on the stones. The steady flow of sewage over these growths allows the microbes to absorb the dissolved organics, thus lowering the biochemical oxygen demand (BOD) of the sewage. Air circulating upward through the spaces among the stones provides sufficient oxygen for the metabolic processes.

Settling tanks, called secondary clarifiers, follow the trickling filters. These clarifiers remove microbes that are washed off the rocks by the flow of wastewater. Two or more trickling filters may be connected in series, and sewage can be recirculated in order to increase treatment efficiencies.

Activated sludge

The activated sludge treatment system consists of an aeration tank followed by a secondary clarifier. Settled sewage, mixed with fresh sludge that is recirculated from the secondary clarifier, is introduced into the aeration tank. Compressed air is then injected into the mixture through porous diffusers located at the bottom of the tank. As it bubbles to the surface, the diffused air provides oxygen and a rapid mixing action. Air can also be added by the churning action of mechanical propeller-like mixers located at the tank surface.

Under such oxygenated conditions, microorganisms thrive, forming an active, healthy suspension of biological solids—mostly bacteria—called activated sludge. About six hours of detention is provided in the aeration tank. This gives the microbes enough time to absorb dissolved organics from the sewage, reducing the BOD. The mixture then flows from the aeration tank into the secondary clarifier, where activated sludge settles out by gravity. Clear water is skimmed from the surface of the clarifier, disinfected, and discharged as secondary effluent. The sludge is pumped out from a hopper at the bottom of the tank. About 30 percent of the sludge is recirculated back into the aeration tank, where it is mixed with the primary effluent. This recirculation is a key feature of the activated sludge process. The recycled microbes are well acclimated to the sewage environment and readily metabolize the organic materials in the primary effluent. The remaining 70 percent of the secondary sludge must be treated and disposed of in an acceptable manner (see Sludge treatment and disposal).

aeration treatment

Schematic diagram of a prefabricated package plant for the aeration treatment of small sewage flows.(more)

Variations of the activated sludge process include extended aeration, contact stabilization, and high-purity oxygen aeration. Extended aeration and contact stabilization systems omit the primary settling step. They are efficient for treating small sewage flows from motels, schools, and other relatively isolated wastewater sources. Both of these treatments are usually provided in prefabricated steel tanks called package plants. Oxygen aeration systems mix pure oxygen with activated sludge. A richer concentration of oxygen allows the aeration time to be shortened from six to two hours, reducing the required tank volume.

Oxidation pond

Oxidation ponds, also called lagoons or stabilization ponds, are large, shallow ponds designed to treat wastewater through the interaction of sunlight, bacteria, and algae. Algae grow using energy from the sun and carbon dioxide and inorganic compounds released by bacteria in water. During the process of photosynthesis, the algae release oxygen needed by aerobic bacteria. Mechanical aerators are sometimes installed to supply yet more oxygen, thereby reducing the required size of the pond. Sludge deposits in the pond must eventually be removed by dredging. Algae remaining in the pond effluent can be removed by filtration or by a combination of chemical treatment and settling.

Rotating biological contacter

In this treatment system a series of large plastic disks mounted on a horizontal shaft are partially submerged in primary effluent. As the shaft rotates, the disks are exposed alternately to air and wastewater, allowing a layer of bacteria to grow on the disks and to metabolize the organics in the wastewater.

Tertiary treatment

When the intended receiving water is very vulnerable to the effects of pollution, secondary effluent may be treated further by several tertiary processes.

Effluent polishing

tertiary treatment of wastewater

(Left) During the filtering step, wastewater from secondary treatment, still containing suspended solids, pours from a trough and percolates through a filter bed made of porous media such as sand, gravel, and anthracite. The filtered water is then piped away for disposal. (Right) In the backwashing step, entrained solids are periodically flushed from the filter media by pumping filtered water back through the assembly. The backwash water, carrying suspended solids, is returned to the beginning of the wastewater treatment process.(more)

For the removal of additional suspended solids and BOD from secondary effluent, effluent polishing is an effective treatment. It is most often accomplished using granular media filters, much like the filters used to purify drinking water. Polishing filters are usually built as prefabricated units, with tanks placed directly above the filters for storing backwash water. Effluent polishing of wastewater may also be achieved using microstrainers of the type used in treating municipal water supplies.

Removal of plant nutrients

When treatment standards require the removal of plant nutrients from the sewage, it is often done as a tertiary step. Phosphorus in wastewater is usually present in the form of organic compounds and phosphates that can easily be removed by chemical precipitation. This process, however, increases the volume and weight of sludge. Nitrogen, another important plant nutrient, is present in sewage in the form of ammonia and nitrates. Ammonia is toxic to fish, and it also exerts an oxygen demand in receiving waters as it is converted to nitrates. Nitrates, like phosphates, promote the growth of algae and the eutrophication of lakes. A method called nitrification-denitrification can be used to remove the nitrates. It is a two-step biological process in which ammonia nitrogen is first converted into nitrates by microorganisms. The nitrates are further metabolized by another species of bacteria, forming nitrogen gas that escapes into the air. This process requires the construction of more aeration and settling tanks and significantly increases the cost of treatment.

A physicochemical process called ammonia stripping may be used to remove ammonia from sewage. Chemicals are added to convert ammonium ions into ammonia gas. The sewage is then cascaded down through a tower, allowing the gas to come out of solution and escape into the air. Stripping is less expensive than nitrification-denitrification, but it does not work very efficiently in cold weather.

Land treatment

In some locations, secondary effluent can be applied directly to the ground and a polished effluent obtained by natural processes as the wastewater flows over vegetation and percolates through the soil. There are three types of land treatment: slow-rate, rapid infiltration, and overland flow.

In the slow-rate, or irrigation, method, effluent is applied onto the land by ridge-and-furrow spreading (in ditches) or by sprinkler systems. Most of the water and nutrients are absorbed by the roots of growing vegetation. In the rapid infiltration method, the wastewater is stored in large ponds called recharge basins. Most of it percolates to the groundwater, and very little is absorbed by vegetation. For this method to work, soils must be highly permeable. In overland flow, wastewater is sprayed onto an inclined vegetated terrace and slowly flows to a collection ditch. Purification is achieved by physical, chemical, and biological processes, and the collected water is usually discharged into a nearby stream.

Land treatment of sewage can provide moisture and nutrients for the growth of vegetation, such as corn or grain for animal feed. It also can recharge, or replenish, groundwater aquifers. Land treatment, in effect, allows sewage to be recycled for beneficial use. Large land areas are required, however, and the feasibility of this kind of treatment may be limited further by soil texture and climate.

Clustered wastewater treatment systems

In certain instances when it is not feasible to connect residences or units to public sewer systems, communities may opt for a clustered wastewater treatment system. Such facilities are smaller versions of centralized treatment plants and serve only a limited number of connections. The technologies used for clustered wastewater treatment may be the same as those used for centralized systems or for individual on-site systems, depending upon the specific applications and degree of treatment required. Upon treatment, effluent from clustered wastewater systems can be discharged via surface or subsurface disposal methods.

On-site septic tanks and leaching fields

In sparsely populated suburban or rural areas, it is usually not economical to build sewage collection systems and a centrally located treatment plant. Instead, a separate treatment and disposal system is provided for each home. On-site systems provide effective, low-cost, long-term solutions for wastewater disposal as long as they are properly designed, installed, and maintained. In the United States, about one-third of private homes make use of an on-site subsurface disposal system.

septic tank

A septic tank before installation.

The most common type of on-site system includes a buried, watertight septic tank and a subsurface absorption field (also called a drain field or leaching field). The septic tank serves as a primary sedimentation and sludge storage chamber, removing most of the settleable and floating material from the influent wastewater. Although the sludge decomposes anaerobically, it eventually accumulates at the tank bottom and must be pumped out periodically (every two to four years). Floating solids and grease are trapped by a baffle at the tank outlet, and settled sewage flows out into the absorption field, through which it percolates downward into the ground. As it flows slowly through layers of soil, the settled wastewater is further treated and purified by both physical and biological processes before it reaches the water table.

An absorption field includes several perforated pipelines placed in long, shallow trenches filled with gravel. The pipes distribute the effluent over a sizable area as it seeps through the gravel and into the underlying layers of soil. If the disposal site is too small for a conventional leaching field, deeper seepage pits may be used instead of shallow trenches; seepage pits require less land area than leaching fields. Both leaching field trenches and seepage pits must be placed above seasonally high groundwater levels.

For subsurface on-site wastewater disposal to succeed, the permeability, or hydraulic conductivity, of the soil must be within an acceptable range. If it is too low, the effluent will not be able to flow effectively through the soil, and it may seep out onto the surface of the absorption field, thereby endangering public health. If permeability is too high, there may not be sufficient purification before the effluent reaches the water table, thereby contaminating the groundwater. The capacity of the ground to absorb settled wastewater depends largely on the texture of the soil (i.e., relative amounts of gravel, sand, silt, and clay). Permeability can be evaluated by direct observation of the soil in excavated test pits and also by conducting a percolation test, or “per test.” The perc test measures the rate at which water seeps into the soil in small test holes dug on the disposal site. The measured perc rate can be used to determine the total required area of the absorption field or the number of seepage pits.

Where unfavourable site or soil conditions prohibit the use of both absorption fields and seepage pits, mound systems may be utilized for on-site sewage disposal. A mound is an absorption field built above the natural ground surface in order to provide suitable material for percolation and to separate the drain field from the water table. Septic tank effluent is intermittently pumped from a chamber and applied to the mound. Other alternative on-site disposal methods include use of intermittent sand filters or of small, prefabricated aerobic treatment units. Disinfection (usually by chlorination) of the effluent from these systems is required when the effluent is discharged into a nearby stream.

Wastewater reuse

Wastewater can be a valuable resource in cities or towns where population is growing and water supplies are limited. In addition to easing the strain on limited freshwater supplies, the reuse of wastewater can improve the quality of streams and lakes by reducing the effluent discharges that they receive. Wastewater may be reclaimed and reused for crop and landscape irrigation, groundwater recharge, or recreational purposes. Reclamation for drinking is technically possible, but this reuse faces significant public resistance.

There are two types of wastewater reuse: direct and indirect. In direct reuse, treated wastewater is piped into some type of water system without first being diluted in a natural stream or lake or in groundwater. One example is the irrigation of a golf course with effluent from a municipal wastewater treatment plant. Indirect reuse involves the mixing of reclaimed wastewater with another body of water before reuse. In effect, any community that uses a surface water supply downstream from the treatment plant discharge pipe of another community is indirectly reusing wastewater. Indirect reuse is also accomplished by discharging reclaimed wastewater into a groundwater aquifer and later withdrawing the water for use. Discharge into an aquifer (called artificial recharge) is done by either deep-well injection or shallow surface spreading.

Quality and treatment requirements for reclaimed wastewater become more stringent as the chances for direct human contact and ingestion increase. The impurities that must be removed depend on the intended use of the water. For example, removal of phosphates or nitrates is not necessary if the intended use is landscape irrigation. If direct reuse as a potable supply is intended, tertiary treatment with multiple barriers against contaminants is required. This may include secondary treatment followed by granular media filtration, ultraviolet radiation, granular activated carbon adsorption, reverse osmosis, air stripping, ozonation, and chlorination.

The use of gray-water recycling systems in new commercial buildings offers a method of saving water and reducing total sewage volumes. These systems filter and chlorinate drainage from tubs and sinks and reuse the water for nonpotable purposes (e.g., flushing toilets and urinals). Recycled water can be marked with a blue dye to ensure that it is not used for potable purposes.

Sludge treatment and disposal

sewage sludge treatment

Mixed sludge received from secondary wastewater treatment is passed through a dissolved-air flotation tank, where solids rise to the surface and are skimmed off. The thickened sludge is pulped with steam, then passed to thermal hydrolysis, where large molecules such as proteins and lipids are broken down under heat and pressure. The hydrolyzed sludge is passed through a flash tank, where a sudden drop in pressure causes cells to burst, and then to anaerobic digestion, where bacteria convert dissolved organic matter to biogas (which can be used to fuel the treatment process). Digested sludge is passed through a dewatering step; the dried solids are disposed of, and the water is sent back to secondary treatment.(more)

The residue that accumulates in sewage treatment plants is called sludge (or biosolids). Sewage sludge is the solid, semisolid, or slurry residual material that is produced as a by-product of wastewater treatment processes. This residue is commonly classified as primary and secondary sludge. Primary sludge is generated from chemical precipitation, sedimentation, and other primary processes, whereas secondary sludge is the activated waste biomass resulting from biological treatments. Some sewage plants also receive septage or septic tank solids from household on-site wastewater treatment systems. Quite often the sludges are combined together for further treatment and disposal.

Treatment and disposal of sewage sludge are major factors in the design and operation of all wastewater treatment plants. Two basic goals of treating sludge before final disposal are to reduce its volume and to stabilize the organic materials. Stabilized sludge does not have an offensive odour and can be handled without causing a nuisance or health hazard. Smaller sludge volume reduces the costs of pumping and storage.

Treatment methods

Treatment of sewage sludge may include a combination of thickening, digestion, and dewatering processes.

Thickening

Thickening is usually the first step in sludge treatment because it is impractical to handle thin sludge, a slurry of solids suspended in water. Thickening is usually accomplished in a tank called a gravity thickener. A thickener can reduce the total volume of sludge to less than half the original volume. An alternative to gravity thickening is dissolved-air flotation. In this method, air bubbles carry the solids to the surface, where a layer of thickened sludge forms.

Digestion

Sludge digestion is a biological process in which organic solids are decomposed into stable substances. Digestion reduces the total mass of solids, destroys pathogens, and makes it easier to dewater or dry the sludge. Digested sludge is inoffensive, having the appearance and characteristics of a rich potting soil.

Most large sewage treatment plants use a two-stage digestion system in which organics are metabolized by bacteria anaerobically (in the absence of oxygen). In the first stage, the sludge, thickened to a dry solids (DS) content of about 5 percent, is heated and mixed in a closed tank for several days. Acid-forming bacteria hydrolyze large molecules such as proteins and lipids, breaking them into smaller water-soluble molecules, and then ferment those smaller molecules into various fatty acids. The sludge then flows into a second tank, where the dissolved matter is converted by other bacteria into biogas, a mixture of carbon dioxide and methane. Methane is combustible and is used as a fuel to heat the first digestion tank as well as to generate electricity for the plant.

Anaerobic digestion is very sensitive to temperature, acidity, and other factors. It requires careful monitoring and control. In some cases, the sludge is inoculated with extra hydrolytic enzymes at the beginning of the first digestion stage in order to supplement the action of the bacteria. It has been found that this enzymatic treatment can destroy more unwanted pathogens in the sludge and also can result in the generation of more biogas in the second stage of digestion.

Another enhancement of the traditional two-stage anaerobic digestion process is thermal hydrolysis, or the breaking down of the large molecules by heat. This is done in a separate step before digestion. In a typical case, the process begins with a sludge that has been dewatered to a DS content of some 15 percent. The sludge is mixed with steam in a pulper, and this hot homogenized mixture is fed to a reactor, where it is held under pressure at approximately 165 °C (about 330 °F) for about 30 minutes. At that point, with the hydrolytic reactions complete, some of the steam is bled off (to be fed to the pulper), and the sludge, still under some pressure, is released suddenly into a “flash tank,” where the sudded drop in pressure bursts the cell walls of much of the solid matter. The hydrolyzed sludge is cooled, diluted slightly with water, and then sent directly to the second stage of anaerobic digestion.

Sludge digestion may also take place aerobically—that is, in the presence of oxygen. The sludge is vigorously aerated in an open tank for about 20 days. Methane gas is not formed in this process. Although aerobic systems are easier to operate than anaerobic systems, they usually cost more to operate because of the power needed for aeration. Aerobic digestion is often combined with small extended aeration or contact stabilization systems.

Aerobic and conventional anaerobic digestion convert about half of the organic sludge solids to liquids and gases. Thermal hydrolysis followed by anaerobic digestion can convert some 60 to 70 percent of the solid matter to liquids and gases. Not only is the volume of solids produced smaller than in conventional digestion, but the greater production of biogas can make some wastewater treatment plants self-sufficient in energy.

Dewatering

Digested sewage sludge is usually dewatered before disposal. Dewatered sludge still contains a significant amount of water—often as much as 70 percent—but, even with that moisture content, sludge no longer behaves as a liquid and can be handled as a solid material. Sludge-drying beds provide the simplest method of dewatering. A digested sludge slurry is spread on an open bed of sand and allowed to remain until dry. Drying takes place by a combination of evaporation and gravity drainage through the sand. A piping network built under the sand collects the water, which is pumped back to the head of the plant. After about six weeks of drying, the sludge cake, as it is called, may have a solids content of about 40 percent. It can then be removed from the sand with a pitchfork or a front-end loader. In order to reduce drying time in wet or cold weather, a glass enclosure may be built over the sand beds. Since a good deal of land area is needed for drying beds, this method of dewatering is commonly used in rural or suburban towns rather than in densely populated cities.

Alternatives to sludge-drying beds include the rotary drum vacuum filter, the centrifuge, and the belt filter press. These mechanical systems require less space than do sludge-drying beds, and they offer a greater degree of operational control. However, they usually have to be preceded by a step called sludge conditioning, in which chemicals are added to the liquid sludge to coagulate solids and improve drainability.

Disposal

The final destination of treated sewage sludge usually is the land. Dewatered sludge can be buried underground in a sanitary landfill. It also may be spread on agricultural land in order to make use of its value as a soil conditioner and fertilizer. Since sludge may contain toxic industrial chemicals, it is not spread on land where crops are grown for human consumption.

Where a suitable site for land disposal is not available, as in urban areas, sludge may be incinerated. Incineration completely evaporates the moisture and converts the organic solids into inert ash. The ash must be disposed of, but the reduced volume makes disposal more economical. Air pollution control is a very important consideration when sewage sludge is incinerated. Appropriate air-cleaning devices such as scrubbers and filters must be used.

Dumping sludge in the ocean, once an economical disposal method for many coastal communities, is no longer considered a viable option. It is now prohibited in the United States and many other coastal countries.

Jerry A. NathansonThe Editors of Encyclopaedia Britannica

Emerging technologies

Experts in the wastewater treatment sector have been working to implement established technologies and to improve environmental rules and regulations to meet water quality goals and human health protection. At the same time, the industry has also been transitioning to prepare for future challenges, such as climate change, changing populations, and aging infrastructure.

Improved treatment methods

Many older wastewater treatment facilities require upgrading because of increasingly strict water quality standards, but this is often difficult because of limited space for expansion. In order to allow improvement of treatment efficiencies without requiring more land area, new treatment methods have been developed. These include the membrane bioreactor process, the ballasted floc reactor, and the integrated fixed-film activated sludge (IFAS) process.

In the membrane bioreactor process, hollow-fibre microfiltration membrane modules are submerged in a single tank in which aeration, secondary clarification, and filtration can occur, thereby providing both secondary and tertiary treatment in a small land area.

In a ballasted floc reactor, the settling rate of suspended solids is increased by using sand and a polymer to help coagulate the suspended solids and form larger masses called flocs. The sand is separated from the sludge in a hydroclone, a relatively simple apparatus into which the water is introduced near the top of a cylinder at a tangent so that heavy materials such as sand are “spun” by centrifugal force toward the outside wall. The sand collects by gravity at the bottom of the hydroclone and is recycled back to the reactor.

Biological aerated filters use a basin with submerged media that serves as both a contact surface for biological treatment and a filter to separate solids from the wastewater. Fine-bubble aeration is applied to facilitate the process, and routine backwashing is used to clean the media. The land area required for a biological aerated filter is only about 15 percent of the area required for a conventional activated sludge system.

Automation

Advanced wastewater purification processes involve biological treatments that are sensitive to processing parameters and to the environment. To ensure stable and reliable operations of physical, chemical, and biological processes, treatment plants quite often need to implement sophisticated technologies involving complex instrumentation and process control systems. Use of online analytical instruments, programmable logic controllers (PLC), supervisory control and data acquisition (SCADA) systems, human machine interface (HMI), and various process control software allow for the automation and computerization of treatment processes with the provision for remote operations. Such innovations improve system operations significantly, thus minimizing supervision needs.

Environmental considerations

Natural treatments, energy conservation, and carbon footprint reduction are some of the key considerations for communities facing energy and electricity challenges. Green technologies and the use of renewable energy sources, including solar and wind power, for wastewater treatment are evolving and will help minimize the environmental impacts of human activities. Ecological and economical natural wastewater treatment and disposal systems have already gained importance in many places, especially in smaller communities. These include constructed wetlands, lagoons, stabilization ponds, soil filters, drip irrigation, groundwater recharge, and other similar systems. The simplicity, cost-effectiveness, efficiency, and reliability of these systems have provided potential applications for such environmentally friendly technologies.

Given that wastewater is rich in nutrients and other chemicals, sewage treatment facilities have gained recognition as resource recovery facilities, overcoming their former reputation as mere pollution mitigation entities. Newer technologies and approaches have continued to improve the efficiency by which energy, nutrients, and other chemicals are recovered from treatment plants, helping create a sustainable market and becoming a revenue generation source for wastewater processing facilities.

Concepts such as nutrient trading have also emerged. The intention of such initiatives is to control and meet overall pollution load targets for a given watershed by trading nutrient reduction credits between point and non-point source dischargers. Such programs can help to minimize nutrient pollution effects as well as reduce financial burdens on societies for costly treatment plant upgrades.

Archis AmbulkarThe Editors of Encyclopaedia Britannica

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Biosolids, sewage sludge, the residues remaining from the treatment of sewage. For use as a fertilizer in agricultural applications, biosolids must first be stabilized through processing, such as digestion or the addition of lime, to reduce concentrations of heavy metals and harmful organisms (certain bacteria, viruses, and other pathogens). This processing also reduces the volume of material and stabilizes the organic matter in it, thus reducing the potential for odours. Use of biosolids in agriculture has become controversial, critics claiming that even treated sewage may harbour harmful bacteria, viruses, and heavy metals.

This article was most recently revised and updated by Michele Metych.

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Also known as: sanitary system, sanitation system, sewage system

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Sewerage system, network of pipes, pumps, and force mains for the collection of wastewater, or sewage, from a community. Modern sewerage systems fall under two categories: domestic and industrial sewers and storm sewers. Sometimes a combined system provides only one network of pipes, mains, and outfall sewers for all types of sewage and runoff. The preferred system, however, provides one network of sewers for domestic and industrial waste, which is generally treated before discharge, and a separate network for storm runoff, which may be diverted to temporary detention basins or piped directly to a point of disposal in a stream or river. See wastewater treatment.

The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Barbara A. Schreiber.

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Environmental infrastructure, infrastructure that provides cities and towns with water supply, waste disposal, and pollution control services. They include extensive networks of aqueducts, reservoirs, water distribution pipes, sewer pipes, and pumping stations; treatment systems such as sedimentation tanks and aeration tanks, filters, septic tanks, desalination plants, and incinerators; and waste disposal facilities such as sanitary landfills and secure hazardous-waste storage impoundments. These municipal works serve two important purposes: they protect human health and safeguard environmental quality. Treatment of drinking water helps to prevent the spread of waterborne diseases such as cholera, dysentery, and typhoid fever, and proper waste treatment and disposal practices prevent degradation of ecosystems and neighbourhoods. Similarly, cleaning the air of pollutant gases and particles as they are generated prevents adverse effects on both human health and the environment.

wastewater-treatment plant

Wastewater-treament plants remove chemical or biological waste from water.

Steady population growth, urbanization, global warming, and industrial development place steadily increasing demands on existing infrastructure, and these demands in turn create a need for the planning, design, and construction of new environmental works. In addition, aging or mismanaged environmental infrastructure can contribute to water scarcity, groundwater contamination, and other environmental or public health problems, and thus its upkeep should be prioritized. Because the provision, operation, and maintenance of these works require a major investment of public funds, concerned citizens as well as municipal officials and decision makers should be familiar with the basic concepts of environmental engineering.

For full discussion of the various elements of environmental infrastructure, see water supply system, wastewater treatment, solid-waste management, hazardous-waste management, pollution control, and air pollution control.

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Emissions trading, an environmental policy that seeks to reduce air pollution efficiently by putting a limit on emissions, giving polluters a certain number of allowances consistent with those limits, and then permitting the polluters to buy and sell the allowances. The trading of a finite number of allowances results in a market price being put on emissions, which enables polluters to work out the most cost-effective means of reaching the required reduction. Emissions trading has been used with notable success to reduce emissions that cause acid rain, and it is currently being used in various attempts around the world to control emissions of greenhouse gases.

Emissions trading in principle

emissions trading

How emissions trading worksAssume two emitting plants, A and B. Each plant emits 100 tons of pollutants (for a total emission of 200 tons), and the requirement is that these emissions be cut in half, for an overall reduction of 100 tons.(Left) In a traditional command-and-control system, each plant might be required to reduce by 50 percent, or 50 tons, to meet the overall reduction of 100 tons. Plant A might be able to reduce at only $100 a ton, for a total expenditure of $5,000. Plant B might have to spend $200 a ton, for a total of $10,000. The cost for both plants to reach the overall reduction of 100 tons would therefore be $15,000.(Right) In a cap-and-trade system, each plant might be given allowances for only half its previous emissions. Plant A, where reduction costs only $100 a ton, might be able to reduce emissions to as little as 25 tons, leaving it with unused allowances for 25 tons of pollutants that it is not emitting. Plant B, where reduction costs $200 a ton, might find it less costly to reduce to only 75 tons and then buy Plant A's unused allowances, effectively paying Plant A to make the 25 tons of reductions that Plant B cannot afford. The overall reduction of 100 tons would still be reached but at a lower overall cost ($12,500) than under the command-and-control system.(more)

An idealized trading scheme might work in the following manner: A regulating authority might assign polluters a certain number of allowances defining the amount of pollutants they are permitted to emit that year. The total number of allowances would represent a certain reduction over the year before, and they would probably be scheduled to go down each subsequent year in order to reach the long-term reduction targets. One group of polluters might be able to take action during the year at relatively little cost that would actually reduce their emissions well below their allowances. In that case, they would face the prospect of finishing the year with unused allowances. A second group of polluters, meanwhile, might find it very expensive to reach their own reduction goals. In order to avoid this cost but also to avoid being fined by the regulating authority for exceeding their allowances, the second group of polluters might be willing to buy unused allowances from the first group—in effect, paying the first group to undertake the extra reductions that are too expensive for the second group. The two would then negotiate a price for the allowances, and the agreed-upon reductions would be undertaken.

The regulating authority would not be concerned with who owned the unused allowances, so long as the total emissions were reduced. Over time, as emissions limits were progressively lowered, the allowances would become fewer in number and fetch a higher price on the market. At some point even the most severe polluter might find it cheaper to invest in pollution reduction than to purchase expensive allowances, though this would not necessarily be the case; some polluters might continue to emit above their allowed levels indefinitely, so long as other polluters were still able to sell them unused allowances at an affordable price. Polluters would continue to invest in emissions-reduction schemes or in emissions trading, depending on which was less expensive at any given time, until the overall reduction target was met.

Acid rain and greenhouse gases

The economic principles behind trading in emissions were explained by American economist Thomas Crocker in his 1966 essay “The Structuring of Atmospheric Pollution Control Systems” and by Canadian economist John H. Dales in his landmark book Pollution, Property, and Prices: An Essay in Policy-Making and Economics (1968). Emissions trading received its first large-scale practical application in the Acid Rain Program run by the U.S. Environmental Protection Agency in the 1990s. In 1990, amendments to the U.S. Clean Air Act of 1970 called for a halving of emissions of sulfur dioxide (SO2) within two decades, along with a parallel ambitious reduction in emissions of nitrogen oxides. Emissions of SO2, mainly by electric power plants, were eventually to be “capped” at 8.95 million tons per year in the continental United States—as opposed to the approximately 17 million tons emitted in 1980. Beginning in 1995, a growing number of power plants (eventually reaching more than 1,000) were brought into the program. Each plant was given a number of annual emission allowances consistent with the nationwide cap, and each plant’s management was left to its own devices either to align its actual emissions with its allowances or to buy allowances from plants that had reduced their emissions below their yearly allowances. By 2010, power plants included in the Acid Rain Program were emitting about five million tons of SO2 per year—well below the program’s cap—and North America’s acid rain problem was universally considered to have been brought under control. Industry and government officials agreed that the reductions were accomplished more efficiently under the cap-and-trade program than they would have been under a more traditional “command-and-control” system of regulations that would have specified how, when, and by how much at each plant emissions were to be reduced.

The world’s first multilateral trading scheme for greenhouse gas emissions was the European Union Emissions Trading Scheme (EU ETS), established in 2005 in response to goals set by the Kyoto Protocol of 1997. The EU ETS is a cap-and-trade system similar in theory to the U.S. Acid Rain Program but vastly more complicated in practice, covering more than 10,000 large installations, from power plants to iron and steel mills as well as all of transport, including flights of non-EU airlines that arrive and depart from EU airports. Among other ambitious goals, the EU ETS aims to reduce the EU’s emissions of greenhouse gases (particularly carbon dioxide) to 20 percent below 1990 levels by the year 2020.

Other so-called carbon-trading schemes exist outside the EU, though none is as ambitious or as complex. Some are limited to individual regions (e.g., Alberta, California), some are undertaken by a collection of regional governments (e.g., the Regional Greenhouse Gas Initiative in the northeastern United States), and some are organized countrywide (e.g., New Zealand, Australia).

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Some proponents of emissions trading argue that no system will be truly effective at reducing greenhouse gases until it is joined by all the world’s major emitters, including not just the EU but also the United States, China, and India. The linking of emissions-trading schemes around the world under the umbrella of internationally agreed-upon reduction targets, so their argument goes, would create a global price on carbon, and a globally accepted price on carbon would in turn eventually result in an efficient reduction of greenhouse gases. Some other analysts, however, argue that no emissions-trading scheme could efficiently reduce greenhouse gases, especially on a global scale. First, they argue, the damage caused to the global environment by each incremental emission of CO2 is very small and perhaps unknowable, making it very hard to put an accurate price on emissions. Second, a global cap-and-trade system would be very difficult to administer and almost impossible to enforce. Political opponents of emissions trading add the argument that any cap-and-trade arrangement would be an unnecessary and burdensome tax on economic activity.

This article was most recently revised and updated by Robert Curley.

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• Introduction

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Anaerobic digestion, chemical process in which organic matter is broken down by microorganisms in the absence of oxygen, which results in the generation of carbon dioxide (CO2) and methane (CH4). Materials high in organic content, such as municipal wastewater, livestock waste, agricultural waste, and food wastes, may all undergo anaerobic digestion. The methane gas produced may be collected and used directly as a fuel for cooking or heating, or it can be burned to generate electricity. Unlike the production of methane from gas wells, anaerobic digestion is a renewable source of energy.

Feedstocks

Several feedstocks exist for the anaerobic digestion process, all of which contain organic matter, including municipal and animal wastewaters and agricultural and food wastes. Anaerobic digestion is frequently used in the treatment of municipal wastewaters, often in a process that also includes aerobic digestion (digestion in the presence of oxygen) and sedimentation. The amount of solids produced from wastewater treatment can be reduced though anaerobic digestion, which in turn reduces the costs associated with their disposal. Similar to human waste, animal waste may also provide the feedstock for anaerobic digestion.

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biogas

Confined feeding operations (CFOs) and concentrated animal feeding operations (CAFOs) are large animal-feeding operations, typically containing more than 300 cattle, 600 swine or sheep, or 30,000 fowl. When that many animals exist on one farm, the resulting manure and wastewater can have significant environmental impacts if they are allowed to simply run over land and into storm sewers and surface waters. The waste depletes water of its oxygen as it degrades, which can be detrimental to aquatic wildlife. Containing the animal waste is often required to protect water quality. Anaerobic digestion reduces the volume of the waste, produces methane for use, and provides a by-product that can be used as fertilizer.

In addition to animal waste, plant waste from agriculture can be processed by anaerobic digestion. In Europe, energy crops are grown for plants dedicated to anaerobic digestion, called biogas plants. (If the plant accepts more than one agricultural feedstock, it is termed a co-digestion plant.) Crops blighted by disease or insects may also be harvested and used as a feedstock for anaerobic digestion.

Most organics can undergo anaerobic digestion, the exception being woody wastes. Wood contains lignin, which most anaerobic microorganisms cannot degrade. However, in the early 21st century, research in the biofuels industry focused on anaerobes that can break down cellulose for the purpose of producing ethanol from woody wastes.

Process

The anaerobic digestion process is used in the treatment of domestic and industrial wastewater. Within the typical wastewater process, both primary (solid) and secondary (liquid) organic wastes can be anaerobically digested. Although that digestion process does produce methane, its primary intent is to reduce the volume of waste solids that must be disposed of. Increasingly, municipal plants are viewing methane as a beneficial by-product of solids processing, and they are capturing the methane to be used on-site. The organic material (or organics) within the low-oxygen environment of landfills also undergoes anaerobic digestion, producing methane.

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The organics that feed the anaerobic digestion process are composed of carbon, nitrogen, and oxygen (C, N, and O). Microorganisms use those organics as a substrate for growth and combine them with water (H2O) to form carbon dioxide (CO2) and methane (CH4). The actual breakdown of organics to methane is not performed by a single microorganism but occurs in three stages through the teamwork of various microorganisms. The first microorganisms convert the organics to a substance that other microorganisms can convert to organic acids. Methanogenic (methane-producing) anaerobic bacteria convert the organic acids to methane.

The amount of methane versus carbon dioxide produced depends on the composition of the original organic substrate being broken down. Sugars, starches, and cellulose produce approximately equal amounts of methane and carbon dioxide. When proteins and fats undergo anaerobic digestion, more methane than carbon dioxide is produced. Digested biogas typically contains a maximum concentration of 70 percent when fats are digested. Digested slaughter-facility wastes can produce approximately 60 percent methane.

Gas production is also very dependent upon temperature. Anaerobic bacteria survive in a broad range of temperatures, but there are two broad categories of methanogens. Medium-temperature (mesophilic) bacteria thrive between 20 and 45 °C (68 and 113 °F), and anaerobic digestion using mesophilic bacteria takes place between 30 and 38 °C (86 and 100 °F). In contrast, the optimum gas-producing temperature range for high-temperature (thermophilic) bacteria is 49–57 °C (120–135 °F). Gas production can be maximized when the temperature is kept within those ranges and the feedstock is constant.

Landfill methane

Although it is not an intentional treatment technique for municipal solid waste, the decomposition of organic matter in the low-oxygen environment of landfills naturally produces gas that is about 50 percent methane and 50 percent carbon dioxide. According to the U.S. Environmental Protection Agency, approximately one-fifth of human-caused emissions of methane come from landfills. Landfill gas can be extracted and collected using a series of wells. The gas can be flared directly if heat or electricity is needed on-site. It can also be processed to increase the methane content, providing a higher-quality gas for pipelines or storage in tanks.

End uses of methane

Methane may be burned to release energy. The energy can then be used for residential heating, cooking, or electricity generation. Methane combusted at wastewater-treatment plants is typically used for on-site heat. This methane would otherwise be flared or vented directly to the atmosphere. Using methane on-site reduces a plant’s overall operating costs.

In the early 21st century, biogas use for the production of electricity was on the rise worldwide, especially in India, Pakistan, and China. In Europe, Germany emerged as the leader in the effort to use biogas for electricity production.

In developing countries, small-scale anaerobic digesters can provide fuel for cooking and lighting within homes. For small farms, it is estimated that the waste from one cow can provide approximately 0.45 cubic metre (about 15.9 cubic feet) of methane per day when digested. The United Nations Development Programme recognizes small-scale home and farm anaerobic digesters as one of the most useful decentralized sources of energy. Small home-based systems allow households to use human, animal, and agricultural wastes to produce their own energy.

Whatever the ultimate use of biogas, it reduces the consumption of nonrenewable methane sources. Biogas also has less environmental impact because its production does not require drilling. Carbon-neutral biogas contributes less to global warming than does methane extracted from the ground, as it releases carbon into the atmosphere that would have been released when the original organic matter naturally decomposed.

Michelle E. Jarvie

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Trickling filter, in wastewater treatment, a bed of crushed rock or other coarse media roughly 2 metres (6 feet) deep and up to 60 metres (200 feet) in diameter. Settled sewage is sprayed over the bed surface and is further purified as it trickles downward, coming in contact with filmy layers of microorganisms (slime) attached to the media. The microorganisms absorb the organic matter in the sewage and stabilize it by aerobic metabolism, thereby removing oxygen-demanding substances from the sewage. Trickling filters remove up to 85 percent of organic pollutant from sewage.

This article was most recently revised and updated by Robert Curley.

Clean Water Act

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Clean Water Act

United States [1972]

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Also known as: CWA, Federal Water Pollution Control Act Amendments of 1972

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Also known as:

Federal Water Pollution Control Act Amendments of 1972

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Wastewater-treament plants remove chemical or biological waste from water.(more)

Clean Water Act (CWA), U.S. legislation enacted in 1972 to restore and maintain clean and healthy waters. The CWA was a response to increasing public concern for the environment and for the condition of the nation’s waters. It served as a major revision of the Federal Water Pollution Control Act of 1948, which had proven ineffective. The CWA was itself amended in 1977 to regulate the discharge of untreated wastewater from municipalities, industries, and businesses into rivers, lakes, and coastal waters.

The CWA is in charge of water quality and sets minimum standards for waste discharges for each industry, as well as regulations for specific problems such as toxic chemicals and oil spills. Point-source pollution, which is discharged by sewers and factories or other sources with a specific origin, is regulated by the Environmental Protection Agency (EPA) and the CWA’s discharge permit program, the National Pollutant Discharge Elimination System (NPDES). NPDES requires any wastewater-treatment plant to obtain discharge permits and follow EPA guidelines for water treatment. The permits place limits on the amount of material that can be discharged. Additionally, many wastewater plants participate in the National Pretreatment Program, which is designed to reduce the number of pollutants discharged into the sewer system by industrial sources and results in safer plant operation and the reuse or recycling of wastewater and sludge.

As a result of the CWA, many municipalities across the U.S. received federal funds to build and improve wastewater-treatment plants. Revisions to the CWA in 1987 removed the original construction grant program and replaced it with a streamlined State Water Pollution Control Revolving Fund. The CWA was also amended to address specific environmental issues such as wetlands protection or Great Lakes water quality. While significant improvements have been made in public health and the environment as a result of the EPA’s enforcement of the CWA, the CWA still faces challenges related to nonpoint-source pollution, such as motor oil in rainwater runoff; sanitary sewer overflows; continued water-treatment infrastructure improvements; and municipal sewage sludge use and disposal.

In October 2022 the U.S. Supreme Court heard arguments in a case, Sackett v. Environmental Protection Agency, that challenged a lower court’s ruling that a privately owned wetland was subject to regulation under the CWA by virtue of its legal status as “navigable waters” or “waters of the United States.” The case raised concerns among environmentalists and others because it presented the Court with the opportunity to adopt a test of regulable wetlands (first proposed in the Court’s plurality opinion in Rapanos v. United States [2006]) that would significantly reduce the number of wetlands that the EPA could protect.

Arthur HolstThe Editors of Encyclopaedia Britannica

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Septic tank, sewage treatment and disposal unit used principally for single residences not connected to municipal sewerage systems. It consists ordinarily of either a single- or double-compartment concrete or fibreglass tank buried in the ground. Solids settle to the bottom of the tank and are partially decomposed by anaerobic bacterial metabolism in the sludge. Grease and floating solids are blocked by a baffle at the top of the tank as the effluent flows out into a drain field, from which it percolates downward into the ground. After several years of use, the accumulated sludge must be pumped out of the tank for disposal at a municipal sewage-treatment plant. When properly designed, installed, and maintained, septic tanks and drain fields provide effective long-term, low-cost, on-site wastewater disposal.

This article was most recently revised and updated by Robert Curley.

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Sewer, conduit that carries wastewater from its source to a point of treatment and disposal. The wastewater may be domestic (sanitary) sewage, industrial sewage, storm runoff, or a mixture of the three. Large-diameter pipes or tunnels that carry a mixture of the three types of liquid wastes, called combined sewers, were commonly built in the 19th and early 20th centuries, and many are still in use. Today combined sewers are no longer built, however, because the large volumes of stormwater that must be carried during wet weather periods often exceed the capacity of sewage treatment systems. Instead, separate sewer systems are now built. Large-diameter storm sewers carry only runoff to a point of disposal; inlet structures called catch basins are built along the pipeline to convey the runoff into the system. A separate network of sanitary sewers, smaller in diameter, carries domestic and pretreated industrial sewage to a municipal wastewater treatment plant where contaminants are removed to prevent water pollution. In some cases, storm sewers may carry runoff to a point of temporary storage and treatment prior to disposal.

The layout and design of a sewerage system depends largely on the topography of the service area. As much as possible, the pipelines are located so that the wastewater flows naturally downhill in partially filled pipes that are not under pressure. Pipe sizes and slopes must be designed in a range that provides adequate scouring velocities at minimum flows but also limits excessive velocities in order to prevent abrasion of the pipe walls at maximum flows. In flat terrain, sometimes sewage must be pumped under pressure through force mains directly to a treatment plant or to a point where it can again flow downhill by gravity.

Sewer pipe must be strong and durable. Relatively small-diameter sewers are made of vitrified clay, asbestos cement, or plastic; reinforced concrete is used for larger sewerage systems, and ductile iron or steel is used for force mains. The joints between sewer pipe sections must be flexible, but they must also be tight enough to prevent leakage of sewage out of the pipeline or of groundwater into the pipeline. Access structures called manholes are located over the pipeline at frequent intervals for pipe cleaning and repair services as well as for sampling and flow measurement. The manholes typically are cylindrical in shape and are made of brick, concrete, or concrete block; a circular cast-iron frame and cover carry traffic loads and keep out surface water. To cross streams, highways, or other obstructions, a short section of the pipeline can be lowered or depressed, forming an inverted siphon. The entire network of sewer pipes, manholes, pumping stations, force mains, inverted siphons, and other appurtenances is called a sewerage system.

See also wastewater treatment.

This article was most recently revised and updated by Robert Curley.

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Abstract

Wastewater treatment is the means by which water that has been used and/or contaminated by humans or nature is restored to a desirable quality. Treatment may consist of chemical, biological, or physical processes or a combination thereof. Water may be treated to any level of quality desired; however, as its purity increases, so does the cost of attaining that purity. The required quality of water is dictated by its intended use, for example, aquatic life, drinking water, or irrigation. The purpose of this chapter is to describe wastewater treatment technologies predominantly in use today. Ultimately, the technology selected as appropriate for one application may not be the optimal for another. Selection will be based on site-specific factors, such as resources available, climate, land availability, economics, etc.

Keywords: Ecotoxicology, Environmental toxicology, Environmental and human health risk assessment, Soil and groundwater pollution, Transport and fate of chemicals in the environment, Waste reclamation, Resource management, Wastewater treatment, Water pollution control, Water resources management

Wastewater treatment is the means by which water that has been used and/or contaminated by humans or nature is restored to a desirable quality. Treatment may consist of chemical, biological, or physical processes or a combination thereof. Water may be treated to any level of quality desired; however, as its purity increases, so does the cost of attaining that purity. The required quality of water is dictated by its intended use, for example, aquatic life, drinking water, or irrigation. The purpose of this chapter is to describe wastewater treatment technologies predominantly in use today. Ultimately, the technology selected as appropriate for one application may not be the optimal for another. Selection will be based on site-specific factors, such as resources available, climate, land availability, economics, etc.

Go to:

Wastewater Management Goals

The overall goal of wastewater management is the sustainable development of natural resources, including protection of public health and the environment. Sustainable development may be defined as the meeting of the needs of society today without compromise of those for future generations. In the context of water quality, sustainable development may be considered as the management of water resources such that current and future uses of this resource are not impaired. Consequently, objectives for water use, treatment, reclamation, and reuse should be consistent with this goal.

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Water Quality Management

To understand the need for a particular degree of wastewater treatment, the concept of water quality management must be introduced. Water must be used and treated in such a way that deleterious effects are minimized, both for the environment and for the next user. From an engineering perspective, the intended use of a water should be determined, water quality requirements for that use delineated, and then treatment or other management techniques based on those requirements accomplished.

The dictionary defines pollution as something that makes the water physically impure, foul or filthy, dirty, stained, tainted, or defiled. Actually, the addition of anything to a water that adversely changes its existing quality constitutes pollution, including heat and sediment. Pollution may be caused by both humans and nature, and the effects may be similar.

The philosophy of water pollution control has changed considerably since the passage of the Public Health Service Act of 1912, which was primarily for the investigation of the spread of waterborne disease. Today, water quality standards are usually limited by aquatic life considerations. For example, the primary drinking water standard for zinc is 5 mg l− 1, while concentrations of zinc as low as 0.001 mg l− 1 may be toxic to aquatic life. The implications of this difference are obvious as the cost to protect aquatic life may be much greater than that for satisfying water quality standards for drinking water. It should be noted that the cost of removal of a contaminant increases considerably when the percentage of removal increases. From the technical standpoint, water can be made as pure as desired; however, from the practical perspective, the cost of achieving a given purity must be considered.

The 1987 Clean Water Act required that wastewater effluents potentially containing toxic contaminants undergo bioassay (whole effluent toxicity) testing to determine if such discharge may result in adverse effects on receiving water biota. Several aquatic species are employed and evaluated for acute and chronic affects. If it is determined that aquatic toxicity is a concern, then evaluation to reduce the toxicity must be conducted. This includes a Toxic Reduction Evaluation (TRE) and if necessary a Toxic Identification Evaluation (TIE) to identify and eliminate the toxicity causing agent (s).

Because of the increasingly stringent limits for selected pollutants due to potential toxicity and/or other deleterious effects on critical ecosystems and public health, the focus on wastewater treatment has shifted to one of wastewater management. This includes prevention instead of treatment/remediation and promotion of ‘clean technologies.’ Emphasis is now given by industry to waste minimization and product life cycle analysis to reduce raw materials, energy and environmental releases, thereby conserving natural resources, reducing risks/liability, and at the same time providing significant cost savings.

Receiving surface waters (lake, river, ocean, or estuary) have an innate ability to accept some contaminants without adverse environmental impact. This so-called self-purification capacity is denoted as the waste assimilative capacity. It is defined as the amount of contaminant that may be discharged into a receiving water, under defined low-flow (and in some cases high flow) conditions which will not result in deleterious effects. This concept often dictates the wastewater treatment requirements imposed on a wastewater discharger. However, where sufficient assimilative capacity does exist, regulations or standards may dictate at least a minimal degree of treatment obtainable by technology-based standards and are based on what can be achieved technologically rather than what is needed environmentally.

Where assimilative capacity is not sufficient to accommodate wastewater effluents and maintain stream standards, compliance to water-quality-based standards is required. Based on the designated use of the stream and results from ecotoxicological evaluations, total maximum daily loads (TMDLs) are determined by state environmental agencies. Considering contributions from non-point-source (diffuse) pollution, background conditions, and a factor of safety, a determination for each discharger is made as to acceptable point source effluent loadings. Accordingly, discharge permit restrictions are then imposed and enforced. These actions typically require a high degree of treatment, thereby shifting focus to resource management, waste reduction, and water reuse options.

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Classification of Pollutants

It is convenient to classify pollutants into four categories as follows: chemical, physical, physiological, and biological. A brief discussion of these is in order as is their method of removal. It should be noted that, depending on the intended use of the water, every receiving water will have a limit as to how much of each of these kinds of wastes can be discharged into the water without adverse effects.

Chemical pollutants can be broadly categorized into inorganic and organic pollutants, where organic materials may be defined as those compounds containing organic carbon. The major problem with organic materials is their conversion to carbon dioxide and water as follows:

Organics+microorganisms+oxygen+nutrients→C02+H20+moremicroorganisms

In as much as aquatic life requires a certain level of dissolved oxygen to live and propagate, it is obvious that if sufficient organic material is placed into the water, oxygen levels may be reduced to inimical concentrations. It is interesting to note that the process described is the same as that taking place in aerobic (presence of free oxygen) wastewater treatment processes. The common measure of oxygen depleting substances is the biochemical oxygen demand (BOD).

A prime consideration of inorganic chemicals is their toxicity. For example, changes in pH may occur from the discharge of soluble salts, and toxicity may occur directly from heavy metals. It should be noted, however, that organics may cause toxicity (e.g., pesticides), and inorganics may cause oxygen depletion (e.g., sulfurous acid). Also, not all materials containing carbon may cause an oxygen demand (e.g., bicarbonate). Some compounds containing organic carbon may be very difficult to biodegrade or non-biodegradable. Aquatic toxicity must be evaluated where appropriate and action taken to eliminate or reduce toxicity when necessary.

Other organic materials include compounds of a toxic nature, such as pesticides, and taste- and odor-producing compounds, including phenols and oils with their tendency to form surface films. The USEPA has defined a list of 126 toxic organic and inorganic chemicals that appear as specific limitations in discharge permits. These are identified as priority pollutants and can be found on the USEPA website www.epa.gov. Volatile organic chemicals (VOCs) such as benzene and toluene may result in public health problems and must be controlled under Clean Air Act legislation. The refractory organics are of particular concern because of the potential long-term cumulative effects of these materials in drinking water and the food chain. The Safe Drinking Water Act (SDWA) also requires the USEPA to list unregulated contaminants that are known or anticipated to occur in public water systems and may require regulation in the future. This list is called the Contaminant Candidate List (CCL) and is updated every five years and can be found on the USEPA website. The EPA uses the CCL to prioritize research efforts in order to make informed regulatory decisions about specific chemicals. The agency determines whether or not to regulate at least five chemicals on the CCL with each publication cycle. Newer organic pollutants, such as pharmaceuticals and personal care products (PPCPs) and endocrine disrupting chemicals (EDCs), have received increasing attention over the last decade. This is because of their wide distribution in surface waters, groundwater, and wastewater effluents, and their effects on the development of a variety of aquatic species, the development of antibiotic resistant pathogens, and possible effects on human health. Regulations for a number of these newer pollutants are currently being evaluated by the EPA. Some are currently banned in the United States and the European Union.

Physical pollutants include color, turbidity, temperature, suspended solids, foam, and radioactivity. Although color is not necessarily harmful, it may be aesthetically unacceptable for drinking water and some industrial uses. Color is often caused by organic colloids, thus making its removal expensive. Color may be the result of natural decay of vegetative organics such as fluvic and humic acids. These can react with free chlorine to form Trihalomethanes (THMs) which are of public health concern in drinking waters. Temperature is an important factor in biological activity and significantly affects chemical, biological, and physical reactions. It may also act synergistically with toxic materials, for example, heavy metal toxicity increases with increasing temperature. Turbidity is caused by colloidal material and/or suspended solids, and its removal requires coagulation and filtration. Suspended solids, which may cause turbidity, can result from wastewater discharges or from natural processes, such as erosion. This may inhibit photosynthesis by reducing light penetration, decrease benthic organism activity by covering the water bottom with sediment, and interfere with fish activity by clogging their gills. Solids may be organic or inorganic. Dissolved solids tend to increase in concentration with reuse. In most cases these are difficult and expensive to remove. Foam resulting from surface active agents may cause aesthetic problems, but developments by the detergent industry have minimized these effects. Surface active agents also may cause a reduction in the rate of oxygen gas transfer into the water. Radioactivity may be the result of fallout, natural sources, or waste discharges and can be incorporated into sludges or biological life or dissolved in the water. Because of the unique effects of radioactive substances, they must be controlled at the source.

Physiological effects of pollution are primarily the result of taste and odor. Although taste and odor problems may be minor in effect, public reaction many times results in magnification of problems and concomitant adverse publicity of the water purveyor. Taste and odor are particularly objectionable when present in drinking water or process water for food where palatability is important. It is significant to note that phenol is detectable at concentrations of 0.001 mg l− 1 and is pervasive in the wastewater discharges of the petrochemical industry. The ability of taste and odor-producing materials to taint fish is also important.

The biological category can also be divided into two subdivisions, public health considerations from waterborne diseases and eutrophication and/or biological growths resulting from nutrient additions.

The causative agents for waterborne disease include virus, protozoa, bacteria, and the helminths,. Contemporary epidemic problems include hepatitis (virally borne), giardiasis, and cryptosporidium (protozoan origin). Probably the most serious waterborne disease is cholera (bacterial origin), which caused major epidemics with high fatalities and morbidities in the 1800s in the United States and continues to be a problem in developing countries. Examples of some water borne diseases are presented in Table I .

Table I

Examples of waterborne infectious diseases

BacteriaCampylobacter jejuni.Enteropathogenic Escheria coli(gastroenteritis)Vibrio cholerae (cholera)Leptospira spp. (leptospirosis)Salmonella typhi, S. paratyphi (enteric fever)Shigella spp. (bacillary dysentery)Yersinia enterocolitica (gastroenteritis)
Legionella pneumophillia (acute respiratory illness)VirusesRotavirus (gastroenteritis, upper respiratory infection)Norovirus (gastroenteritis)Hepatitis A (infectious hepatitis)Hepatitis E (infectious hepatitis)Enteroviruses (including poliovirus)ProtozoaEntamoeba histolytica (amoebic dysentery)Cryptosporidia spp. (cryptosporidiosis)Giardia lambia (giardiasis)HelminthsDracunculiasis (guinea-worm disease)Schistosoma spp. (schistosomiasis; Bilharzia)

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The second category, which may be called secondary biological pollution, is the deterioration of water quality resulting from the addition of phosphorus and/or nitrogen to receiving waters that may be from wastewater discharges or from pollution with no single point source (diffuse pollution). When excessive biological growths and associated water quality problems occur in lakes and estuaries, the phenomenon is known as eutrophication. Eutrophication is a natural geological process that may be accelerated by human cultural activities. Cyanobacteria (blue-green algae) can flourish in eutrophic waters. Some of these organisms are capable of producing toxins that have adverse human health effects, including liver, gastrointestinal, and nervous system effects. In many parts of the world including the U.S. water supply systems have been compromised due to these toxins. This impact is expected to worsen due to the effects of climate change.

It should be noted that nutrient removal (i.e., phosphorus and nitrogen removal) has been a major impetus for advanced wastewater treatment processes for discharges being made into affected water bodies.

Pollutants may also be classified as conventional, toxic, or nonconventional. Conventional contaminants are typical of domestic sewage and include BOD, suspended solids, pH, coliform, and oil and grease. Toxic pollutants include priority pollutants and other constituents resulting in aquatic toxicity and/or affecting public health. These may include behavioral or physiological abnormalities, cancer or genetic mutations upon exposure. Nonconventional pollutants are defined by USEPA as those that are neither conventional nor toxic. These include chemical oxygen demand (COD), total organic carbon (TOC), and nutrients (phosphorous and nitrogen) among others. The type and degree of treatment will depend on the classification of contaminants and that of the receiving waters.

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Classification of Wastewater Treatment Methods

Wastewater treatment processes are categorized as source treatment, pretreatment, primary treatment, secondary treatment, and tertiary or advanced wastewater treatment.

Source treatment is used to remove toxics and/or other undesirable contaminants to prevent intermingling with other waste streams. This approach offers opportunities for reuse of these constituents such as metals, etc. Conventional treatment includes pre- and primary treatment followed by secondary-treatment processes. When necessary tertiary treatment processes are included in the treatment sequence to remove specific constituents to very low residue levels. Pretreatment is employed to render the raw wastewater compatible and/or amenable for subsequent treatment processes. Consideration is given to those constituents that pass through, interfere with, or accumulate in the sludge or are otherwise incompatible with following treatment processes. Equalization, spill retention, neutralization for pH adjustment, nutrient addition, toxics or inhibitory substance removal, oil and grease removal, and solids removal by flotation, sedimentation, or filtration are typical pretreatment processes. Primary treatment is a subset of pretreatment methods and involves physical separation by screening, grit removal, and sedimentation.

Depending on the amount of organics contained in the solid material, primary treatment may remove a significant portion of the oxygen-demanding substances (BOD). A well-designed and operated primary plant may remove as much as 35–40% of the BOD and as much as 60–65% of the settleable solids for municipal wastewaters.

Secondary treatment adds a biological process after primary treatment, which is commonly either activated sludge or trickling filtration for municipal wastewaters. Typically activated sludge or a modification of suspended growth treatment systems is used for industrial wastewater to achieve a high-quality effluent. These biochemical processes are typically aerobic and are the same as previously described as occurring in a river where organics are oxidized to carbon dioxide and water.

A well-operated and designed secondary treatment plant can be expected to remove 85–95% of both BOD and suspended solids. Under existing regulations in the United States, all discharges must be subjected to at least secondary treatment.

Conventional treatment is described by Best Conventional Treatment Technology (BCT) and is designed to remove conventional pollutants such as BOD, TSS, etc. common to municipal wastewaters. However, BCT does not effectively remove many constituents of present-day concern, especially those of industrial wastewater origin. These include many VOCs, toxics, non-biodegradable organics, persistent organic pollutants (POPs), nutrients and emerging contaminants such as EDCs and PPCPs. Hence, additional treatment technology is required.

Tertiary treatment may be defined as treatment in addition to primary and secondary processes. It may include precipitation, filtration, coagulation and flocculation, air stripping, ion exchange, adsorption, membrane processes, nitrification, and/or denitrification, and other processes. Those processes may be integrated into the secondary treatment plant or added onto the secondary effluent. Tertiary or advanced wastewater treatment can attain virtually any removal efficiency desired. However, as previously noted, as the percentage of contaminant removal increases, so does the cost of attaining it. These technologies are often referred to as Best Available Technology Economically Achievable (BTEA) and are applied to meet stream standards or to comply with TMDL requirements.

Tertiary treatment is employed to remove toxics, persistent organics, nonconventional pollutants, nutrients, etc. and is typically considered as BATEA. Tertiary treatment systems following secondary treatment, however, may not be efficient at industrial facilities because of the need for treatment of a large volume of flow with low contaminant concentrations. Many tertiary processes also may not be pollutant-specific. Generally, the most cost-effective approach is to address the problem at the source where flows are low and specific pollutants are present at high concentrations. Applicable technologies for source treatment will depend on the constituents in the process wastewater targeted for removal. For example, if VOCs and ammonia are to be removed, then air or steam stripping should be evaluated. If heavy metals are of concern, then oxidation/reduction, precipitation, filtration, ion exchange, and membrane processes may be investigated. Organic chemicals may require chemical oxidation, wet air oxidation, anaerobic treatment, granular activated carbon (GAC), polymeric resins, or reverse osmosis for effective removal.

Special mention should be made of the solid material removed in any of these processes since residuals disposal is a major problem in wastewater treatment. Sludges are particularly troublesome because of their high water content, concomitant large volumes, and concentration of heavy metals, viruses, protozoa, and other constituents capable of causing environmental and public health harm. Costs of treatment may be one-half or more of that of the aqueous waste stream. Many of the processes mentioned in the preceding paragraphs produce solids. Solids from primary and secondary clarifiers must be effectively managed. Residual solids usually undergo a series of treatment steps involving thickening, dewatering, and final disposition or reuse. Organic sludge may also require stabilization prior to final disposal. Stabilization may be achieved by digestion [aerobic or anaerobic (no oxygen present)], lime stabilization, or by other means. Sludge thickening is typically accomplished by gravity, flotation, or centrifugation methods. Centrifuges, belt filters, and filter presses are dewatering options. The selection of unit processes and their sequence will depend primarily on the characteristics and volume of the sludge and on the final disposition or reuse option selected.

Ultimate disposal choices include incineration, landfill, land disposal (lagooning or application to land for reuse) or other reuse alternatives. Since this material is a resource, it is important that opportunities for reuse be fully considered. It is the ultimate disposal method selected that may significantly influence the unit operations selected for treatment.

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Wastewater Characterization

It is mandatory that the composition and characteristics of a wastewater be known and understood in order to design and operate a wastewater treatment plant. For example, the BOD is a measure of the organic material present and its removal depends on its form. This may be suspended, colloidal, dissolved, molecular type, etc. Solids characteristics will determine the sludge handling and transport facilities. pH may indicate the metals speciation, toxicity, the and/or the need for neutralization. Oxygen content and oxidation reduction potential (ORP) may demonstrate the need for odor control if a lack of dissolved oxygen is present as well as chemical speciation. Grease and oil may cause operational problems and may require special removal facilities.

Wastes originating from industry may be toxic or inhibitory to biological processes, and thus their discharge to a municipal treatment plant must be regulated. Pollutants may include heavy metals, VOCs, priority pollutants, grease and oil, etc. Pretreatment ordinances are used by municipalities to control discharges into municipal sewerage systems.

A major consideration in characterizing wastewaters is the flow since it may vary considerably and contain different contaminants in different concentrations at different times. For example, one would expect to find low flows occurring at night and peaks occurring during periods of maximum water use for domestic wastewaters. Industrial waste flows are generally more random and must be analyzed statistically based on probability analysis. Sampling of wastewaters is often done in accordance with flow so that the mass of constituents can be determined on a weighted average basis (composite sampling).

Whereas the characteristics of municipal sewage are relatively constant, industrial waste characteristics and parameters of concern can change significantly. Important industrial waste parameters that are of significance to a given industry are defined by a Standard Industrial Classification (SIC) grouping. Wastewater characterization and effluent discharge requirements under the National Pollution Discharge Elimination System (NPDES) permit system are based on SIC classifications. The strength and volume of industrial wastewaters are usually defined in terms of units of production (i.e., gal bbl− 1 beer and lb BOD bbl− 1 beer for a brewery) and variation in characteristics and flow by statistical distribution. Industrial waste of organic nature can be correlated to municipal waste loadings by the use of population equivalents. Typically 0.17 lb BOD per capita per day is generated for domestic wastewaters. Assuming an industry generates 17 000 lb BOD per day, then this would be equivalent to a population of 100 000 people. Because of the inherent variability in industrial waste characteristics, treatability studies are often necessary to determine design parameters and potential pretreatment requirements.

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Objectives of Wastewater Treatment

The processes introduced will be examined in the following for their role in treating the various components constituting a wastewater. The prime objectives are threefold: (1) separate the solid from the liquid fraction and concentrate the solids collected from the carrier water; (2) remove and/or render innocuous materials that will cause adverse effects when the effluent and resultant residuals are subjected to ultimate disposition; and (3) maximize reuse potential of treated wastewater and residuals. It is instructive to note that only 0.1% of domestic sewage is solids, the remainder being the carrier water.

In general, less than 50% of the waste material in domestic sewage remains in suspension, thus allowing separation by straining, skimming, or settling. These residuals must be destroyed or rendered removable. This is accomplished by biological, physical, or chemical means.

During chemical treatment the coagulating chemicals combine with the finely divided and colloidal (non-settleable) material to form settleable flocs. In aerobic biological treatment, living organisms metabolize finely divided colloidal and dissolved biodegradable substances and convert them into carbon dioxide and water and settleable films, slimes, or flocs, primarily consisting of cell material.

Physical treatment may involve adsorption processes; where, for example, contaminants containing a high affinity for activated carbon may be removed.

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Wastewater Treatment Processes

Wastewater treatment plant design is based on the selection and sequencing of various unit operations. A schematic illustrating integration of processes capable of treating a variety of wastewaters is shown in Figure 1 . Selection of a combination of processes depends on the characteristics of the wastewaters; the required effluent quality (including potential future restrictions); costs; and, availability of land. As previously indicated, treatment methods can be classified as pretreatment/primary treatment; secondary treatment; tertiary treatment; sludge treatment/stabilization; and, ultimate disposition or reuse treatment technologies for residuals.

Figure 1

Typical wastewater treatment processes.

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Pretreatment/Primary Treatment

Pretreatment methods are used to render the wastewater compatible with and/or amenable to subsequent treatment processes. Typical processes include equalization, neutralization, and oil and grease separation. Primary treatment involves physical separation for municipal wastewaters and usually consists of screening or comminution, followed by grit removal, and then sedimentation prior to secondary treatment.

Screening/Comminution

Screening is used to remove large, objectionable, solid matter that is removed periodically to prevent flow obstruction and head loss. The removed materials are putrescible and are usually buried or incinerated. A comminutor acting like a large ‘garbage grinder’ may be used to homogenize the solids as an alternative to screening. To protect the machinery the comminutor generally follows grit removal. The homogenized solids contribute to the organic load to the treatment facility, and hence screening is often the method of choice.

Grit Removal

Grit is composed of small coarse particles of sand, gravel, or other minute mineral material. Grit is removed to prevent damage to mechanical equipment and to maintain tank volume capacities. Grit may be removed in an aerated chamber where the amount of air is just sufficient to keep the organic matter in suspension and allow the heavier inorganic material to settle. Grit may also be removed by controlling the velocity of flow through a chamber such that the gritty material will settle and the organics remain suspended. Grit removed is typically washed and land disposed.

Oil and Grease Removal

Excessive oil, grease, and finely divided suspended solids should be removed prior to discharge into the primary sedimentation tank or aeration basin. This can be accomplished by employing processes including gravity separation with skimming and/or flotation. An API separator or parallel plate/corrugated plate oil separator may be employed effectively to separate free oil by gravity allowing the lighter-than-water oil globules to rise to the tank surface to be skimmed off. The API gravity separator is designed to remove oil globules 0.015 cm or greater and can achieve an effluent oil of less than 50 mg l− 1. The corrugated plate separator (CPS) with a narrow separation space can remove oil globules 0.01 cm or greater to as low as 10 mg l− 1; however, it is more affected by hydraulic variation. Flotation can be accomplished by introducing air under pressure into recycled effluent water and then allowing the pressurized air–water mixture to escape at atmospheric pressure in the flotation unit as minute air bubbles. Oil globules, sludge flocs, and suspended solids are floated by these bubbles. The air–oil and/or air–solids mixture rises to the surface where it is skimmed off. Chemical coagulants are generally added to help break oil emulsions and promote flocculation and enhance bubble attachment and flotation. Flotation usually follows API separation. A schematic diagram of a dissolved air flotation unit is shown in Figure 2 . Where VOCs are of concern, API separators and flotation units are often covered and the space purged with methane or nitrogen to minimize explosion hazard.

Figure 2

Dissolved air flotation unit.

(Courtesy of Komline–Sanderson Company)

Equalization and Neutralization

It is sometimes necessary, especially for industrial wastewaters, to install a basin to neutralize large fluctuations in pH and/or concentrations of contaminants in the incoming flow to the treatment plant. Control of fluctuations in flow with time may be required and necessitates a holding tank to equalize the flow variability. The use of equalization will assist in maintaining a relatively uniform flow and/or concentration through the plant and to the receiving water. Equalization is perhaps the most important unit operation in the treatment train for industrial wastewaters because of the desire to approach quasi steady-state conditions for design equation assumptions to hold true. Neutralization usually follows equalization so that acidic and alkaline streams can be partially neutralized in the equalization basin. Acidic wastewaters can be neutralized with lime, caustic, or limestone. Alkaline wastewaters can be neutralized with H2SO4 or HCl or by using flue gas (CO2). Usually a two-step process is required for pH control because of the logarithmic nature of pH. A pH of 6.5–8.5 is generally required prior to biological treatment.

Primary Sedimentation

Settleable solids are removed by introducing the wastewater, after pretreatment, into a large rectangular or circular tank where solids settle by gravity. The supernatant overflows weirs and proceeds to secondary treatment for aerobic conversion to CO2 and water by biological oxidation. Primary clarification also acts as a barrier for oil and grease to prevent operational problems during subsequent treatment. Since solids will be collected at the bottom of the settling tank, provision must be made for their removal. This is usually accomplished by utilizing a continuous belt device as shown in Figure 3 . The solids (sludge) are then pumped from the sludge hopper to a sludge digester or other sludge treatment unit process. Note that the secondary sedimentation tank follows biological treatment. As shown in Figure 3, it differs from the primary tank because the provision for scum removal will generally not be required. Additionally, in place of a belt conveyor, a vacuum draw-off is often employed to remove solids quickly for activated sludge applications. It should be noted that chemicals are sometimes added prior to settling to enhance solids removal. The efficiency of solids removal for both primary and secondary clarification is a function of the overflow rate (gal ft− 2 day) which is essentially the velocity of the liquid exiting the tank. The settling velocity of the solids must be greater than the overflow rate if removal is to be effective. Liquid retention time must also be sufficient for efficient solids separation. It should be noted that for treatment of soluble industrial waste the primary settling tank is usually replaced with an equalization basin.

Figure 3

Gravity settling tank

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Secondary Treatment

Secondary treatment utilizes some form of biological treatment following pretreatment/primary treatment. Since much of the organic material in a wastewater may be colloidal or dissolved, the processes described thus far will be ineffective in its treatment. It has previously been shown that organic matter will be oxidized to carbon dioxide and water in the presence of microorganisms, oxygen, and nutrients. Thus, the conditions required for wastewater treatment are an adequate number of acclimated microorganisms that can metabolize the organic material, an oxygen supply, nutrients, a means of intimate contact between the microorganisms and the food (wastewater), and a method of containment. The process is identical to that occurring in an aerobic waterway, except that in the wastewater treatment plant, the process is optimized by reduced time requirements and a continuous supply of oxygen to maintain an aerobic state.

There are numerous ways to design a biological wastewater treatment process; however, the two most commonly used are the activated sludge process and the trickling filtration process. In the activated sludge process, the fine, suspended, and colloidal and soluble organic materials are brought into intimate contact with a biologically active sludge maintained in suspension in the tank by introducing air that not only serves to maintain turbulence and maximum contact, but supplies the microorganisms with the oxygen required for their metabolism. The activated sludge performs the work of adsorbing, assimilating, and flocculating the waste material.

The trickling filtration process is identical to the activated sludge process in principle. However, instead of the water flowing through the suspended sludge containing the microorganisms, the waste material flows over a suitable surface to which the microorganisms adhere. When wastewater flows over the fixed film surface, growth of bacteria and other microorganisms occurs. These microorganisms create a slimy, gelatinous film that transfers the matter held in suspension, both colloidal and in solution, to the microorganisms, which remove food (substrate) needed for their growth and transfer back to the liquid the end products of decomposition, including (in the aerobic process) nitrates, carbon dioxide, and sulfates. As is the case with the activated sludge process, the microorganisms working in the trickling filtration process need a continuous food supply, adequate oxygen, a suitable support, and appropriate nutrients.

The processes taking place in any aerobic biological treatment plant can best be described schematically as shown in Figure 4 , where cell material is produced by synthesis (cell growth) and end products are generated by endogenous respiration (cell death), depending on the existing ratio of food to microorganisms (F M− 1 ratio) in the process. Thus, part of the energy may be utilized in reproducing new bacterial cells and the rest of the energy used in converting waste products to carbon dioxide and water. If the food supply becomes meager, the bacteria will eat themselves and bacterial cells will be converted into end products. This process, when the food-to-microorganism ratio is low is called endogenous respiration. It can also be seen from Figure. 4 that part of the waste material will be non-biodegradable. This is the residue of the waste material that will not be removed, either as cell material or as non-biodegradable residues produced during metabolism termed soluble microbial products (SMPs). The endogenous respiration process is analogous to a starving human who uses his own tissue to provide energy to sustain life processes. Note that SMPs are also generated during synthesis.

Figure 4

Biological stabilization of organic waste materials.

Figure 5 schematically demonstrates a complete-mix biological wastewater treatment process, where Q is the flow volume, S is the concentration of organics (substrate), V is the volume of the tank, M is the mass of microorganisms in the tank, s is the concentration of organics in the tank, and R is the fraction of return flow. The mass of microorganisms per day wasted divided into the inventory of microbes in the reactor is termed the sludge age or mean cell residence time (MCRT). This is used for system control to maintain a desired physiology of the biomass present. The required time for stabilization for industrial wastewaters, which are often soluble, is usually longer than that required for municipal wastewaters and will vary depending on the complexity of the waste. Retention time required may be hours to days and must be determined by treatability studies. Temperature effects are also significant depending on the nature of the wastewater, temperature extremes and temperature variation.

Figure 5

Complete mix biological reactor.

Activated Sludge Process

The activated sludge process consists of maintaining an active biological floc in a tank supplied with oxygen so that maximum contact is made between the incoming wastewater and the microorganisms in the floc. In the conventional process, a rectangular tank is usually used and the wastewater is introduced into a concentration of microorganisms maintained in the tank. Typically, air is introduced, either in the form of bubbles through diffusers or by turbulent agitation of the liquid by an impeller. In some cases pure oxygen is used in place of air. The microbe concentration is maintained in the tank by returning a certain portion of the sludge that passes through the tank and is settled out in a secondary sedimentation basin. The activated sludge process produces new cell material by synthesis which will become part of the activated sludge mass. Part of the settled material therefore, must be disposed of, and a portion must be introduced into the incoming raw wastewater in order to have an active population of microorganisms that will feed on the organic compounds.

As might be expected, the design of an activated sludge process will depend on the ratio of the food, or waste, to the microorganisms, or activated sludge. For domestic sewage characterized by a high suspended solids and colloidal content, most organic materials are adsorbed by the sludge floc in 15–45 min, although most conventional plants are designed with at least 30–90 min of contact time for adequate adsorption by the sludge floc. Retention times may be 24 h or longer for extended aeration package plants. With the activated sludge process, it is possible to obtain removals of BOD on the order of 95% or greater with a higher quality effluent than with most other biological oxidation processes. Many modifications of the activated sludge process exist, including a high-rate process where the food to-microorganism ratio is high, thus producing more sludge, typically used for pretreatment; a step-aeration process, where the influent is added at intervals along the aeration tank; tapered aeration, where the introduction of air is varied along the length of the tank, the higher concentration being at the influent point of the tank; and the contact stabilization process, where a portion of the sludge is aerated separately, thus adding flexibility to the process. Most conventional activated sludge basins treating municipal wastewaters are designed for plug flow to minimize hydraulic retention time and optimize settling properties of the floc. In a true plug flow unit all particles entering the reactor stay for an equal amount of time. This of course is not possible in practice. However, plug flow can be approached by dividing the aeration tank into a series of reactors. With complete-mix reactors the incoming wastewater is completely mixed with the reactor contents upon entry. Because of its ability to absorb shock loadings and reduce toxic/inhibitory constituents by dilution to below threshold levels it is often used for treating industrial wastewaters. With the increasing need for nutrient removal staged reactors are often used with combinations of anaerobic, anoxic and aerobic cells incorporating internal recycle for both phosphorus and nitrogen biological removal.

A modification of the activated sludge process is called extended aeration, where long detention times are given to the aeration operation. It is usually designed for complete-mix conditions. This means that a high solids content or a low food-to-microorganism ratio and long sludge age will exist. Thus, endogenous respiration of the sludge will occur and the sludge will ‘burn itself up.’ The process is sometimes called complete oxidation, although there will always be some biological residue, inorganics, and solids that will necessarily emanate from the system. Because of the long sludge age, nitrogen is converted to nitrate within the reactor, thereby reducing the oxygen demand of the effluent on the receiving water. The process of extended aeration is frequently used in small installations such as schools, subdivisions, and motels. Many industrial plants employ extended aeration to enhance priority pollutant removal, reduce toxicity, and PPCPs and EDCs due to the longer mean cell residence time, MCRT (sludge age). Priority pollutants can be reduced to μg l− 1 levels and BOD soluble to<10 mg l− 1. Figure 6 shows some of the modifications of the activated sludge process commonly employed.

Figure 6

Activated sludge process modifications

The complete mix activated sludge system is generally employed for industrial waste treatment since it maximizes dampening of fluctuations of influent wastewater quality, including toxicity. However, the process for readily degradable wastes may tend to promote the growth of filamentous microbes, which do not settle well in the secondary clarifier. For these cases a selector may be employed preceding the aeration basin. In a selector, degradable organics are removed by the floc due to biosorption and therefore are not available as a food source for the filaments. A contact time of approximately 15 min is generally used.

Another modification of the activated sludge process popular for both municipal and industrial wastewaters is the sequencing batch reactor (SBR). This is a combination of complete mix and plug flow operated on an intermittent basis,that is, aeration, sedimentation, and decanting of effluent all in the same basin. This system has been shown to provide a good settling floc and an effluent of high quality low in nutrients without the need for an external clarifier. The system offers low cost and high flexibility. The SBR utilizes two or more basins operating in parallel such that when one is filling the other is emptying.

Lagoons and Oxidation Ponds

Stabilization ponds are probably one of the oldest wastewater treatment processes in existence and are still used in many locations in the United States today. They can be used alone or in combination with other wastewater treatment processes. Design and utilization depend on many factors, including weather, land availability, purpose, and location. Detention time varies from 7 to 180 days, depending on the type of pond and climate conditions.

Ponds can be classified into four categories: facultative, aerated, aerobic, and anaerobic, the most common being the facultative pond.

Facultative ponds are usually 6–8 ft in depth and operate aerobically in the upper layers and anaerobically in the lower depths. Oxygen in the upper portion is supplied by photosynthesis and surface reaeration. The organic loading is based on climate and on surface area which must be sufficiently low to maintain dissolved oxygen produced by algae. The algae present in the effluent may create problems however. The detention time of a facultative pond will vary from 30 to 180 days or more depending on climate conditions and nature of the wastewater. Effluent BOD values range from 20 to 60 mg l− 1 and effluent suspended solids from 30 to 150 mg l− 1 in warmer climates due to algae content. Multiple ponds in series are recommended for greater operational flexibility and to prevent short-circuiting.

Aerated lagoons are supplied with oxygen by mechanical or diffused aeration and are usually 6–20 ft deep with detention times varying from 3 to 12 days. Hence, large land areas are required, although less than for facultative ponds. The aerated lagoon can be used for pretreatment or may be designed in series to achieve a higher quality effluent. In a two or three basin system, the first basin is fully mixed, thereby maintaining all solids in suspension. This maximizes the organic removal rate. A second basin operates at a lower power level, thereby permitting solids to deposit on the bottom. The solids undergo anaerobic degradation and stabilization. A third basin is frequently employed for further removal of suspended solids and enhanced clarification. Aerated lagoons are employed for the treatment of nontoxic or nonhazardous wastewaters such as food processing and pulp and paper.

Aerobic or maturation ponds are about 18–36 in. deep and maintain oxygen throughout their depth. The oxygen is supplied by photosynthesis and surface reaeration, which is sometimes aided by mixing. These high-rate ponds are limited to warm, sunny climates and have a detention time of 3–5 days. In addition, unless algae removal is practiced, the effluent will contain a high percentage of suspended solids. These ponds will usually produce an effluent of high microbial quality.

Anaerobic ponds have such heavy loading that no aerobic zone exists. They are usually used for strong industrial or agricultural wastes as pretreatment. They are 8–15 ft deep and have detention times of 20–50 days. A major problem is with odor produced from the anaerobic process. Addition of sodium nitrate may be used to reduce or eliminate this problem.

Trickling Filtration

As previously mentioned, the trickling filtration process is similar to the activated sludge process, except that the microorganisms working to stabilize the organic waste material are attached to a fixed bed rather than being suspended. Following pretreatment and sedimentation the wastewater is distributed from rotary nozzles over the bed, which usually consists of coarse, rough, hard material that gives support to the biological film. The organics in the wastewater are oxidized after assimilation by the bacteria. Periodically, the film will become so thick that it can no longer be supported on the medium and will slough off and be discharged into the effluent from the filter. This sludge will then go to the secondary settling tank and be removed with that from the primary settling tank. The trickling filtration process is said to be advantageous because it can provide good performance with a minimum of skilled operator attention and use less energy. However, the process is highly temperature dependent and will not always perform in accord with the requirements of present-day regulatory agencies. Other variables affecting performance include the organic and hydraulic loading rates and the biodegradability of the wastewater. While effluent quality is less than that from the activated sludge process, quality can be enhanced by following the trickling filter with a biological contactor. The contactor is usually designed for a retention time of 15 min and a solids content similar to that maintained in the activated sludge process. For the treatment of industrial wastewaters, a trickling filter is considered a pretreatment process usually designed to remove approximately 50% of the BOD. Note that recirculation of the effluent into the influent is commonly practiced to reduce influent organic concentration and maintain a ‘wetted’ filter growth. Both carbonaceous and nitrogenous oxygen demand can be reduced using trickling filters.

Figure 7 is a schematic diagram of a typical ‘old style’ rock filled trickling filter installation. Oxygen is supplied because of the ‘open-air’ nature of the filter, and the wastewater is applied to the filter medium via the distributor, which rotates because of the momentum induced by the carrier water. The medium shown is stone, although today filters utilize synthetic media such as PVC, which allows greater depths of filtration and a larger specific surface for microbial growth. Multi-stage filters can be used if needed to comply with more stringent effluent standards. Filters may also be covered and off gases treated to reduce or eliminate odor problems.

Figure 7

Schematic diagram of a rock filled trickling filter.

Membrane Bioreactors (MBRs) and Moving Bed Bioreactors (MBBRs)

Membrane Bioreactors (MBRs) consist of a biological reactor with suspended biomass and solids removal by ultra- and microfiltration membranes. These can be used for municipal or industrial wastewaters. The MBRs allow for a much higher biomass concentration to be maintained, thereby allowing smaller bioreactors to be used and saving space. Separation of solids by membrane filtration eliminates the need for secondary sedimentation, and small pore size prevents the discharge of most pathogens. The MBRs can be operated with a longer solids retention time, allowing for more complete oxidation of organics and the maintenance of a population of slow-growing bacteria capable of nutrient, EDC and PPCPs removals and reduced biosolids generation. The disadvantage of MBRs is their high capital costs, periodic membrane replacement, high energy costs and need to control membrane fouling. They offer a competitive alternative when nutrient removal is required. Energy costs have recently been significantly reduced and comparable with advanced wastewater treatment systems.

Moving Bed Bioreactor (MBBR) technology is an advanced secondary wastewater treatment process that incorporates attached growth media within a suspended growth reactor in order to increase the amount of biomass in the treatment basin. It has a smaller footprint compared to conventional suspended growth systems. Existing aerated treatment process can be easily retrofitted to an MBBR process by adding the plastic media and effluent screens. Because of longer sludge retention times, enhanced nitrification and priority pollutant removal is achieved.

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Anaerobic Treatment

Anaerobic treatment processes involve the biological breakdown of organic waste to methane and carbon dioxide gases in the absence of oxygen. Because of lower cost compared to aerobic processes, the beneficial use of methane production, low sludge production, and low energy and nutrient requirements, anaerobic processes have become more attractive alternatives for the stabilization of certain wastes, in particular high-strength industrial wastes (e.g., food industries) and biological sludge. Now over 850 anaerobic treatment systems are in operation globally with about 75% of these treating wastewaters from the food or related industries. Today, more than 60 anaerobic treatment systems are being employed in the chemical and petro-chemical industries. Examples of anaerobic processes are anaerobic filter reactor, anaerobic contact process, fluidized-bed reactor, upflow anaerobic sludge blanket, ADI-BVF process, and expanded granular sludge bed process. These processes are discussed in detail in other texts including Eckenfelder et al., Metcalf & Eddy, etc.

Septic Tanks

A discussion of biological treatment would not be complete without mentioning the septic tank, inasmuch as a large segment of the population is still served by this primitive device, as shown in Figure 8 . From previous discussion, it can be seen that the process is anaerobic, will accumulate solids, and unless periodically pumped out (every 2 to 3 years) will discharge objectionable material. The discharge from such a tank usually flows into a designed drain field and ultimately into the groundwater and/or surface water. A well-designed drainage system into a suitable soil is mandatory since the septic tank itself acts only as a settler and its discharge remains high in soluble organic and microbial contaminants. Proper hydrogeologic conditions are therefore critical in effective drainage field treatment.

Figure 8

Septic tank.

Residuals (Sludge) Treatment

One of the most pervasive problems in water pollution control is the disposal of the solids produced in the various separation processes. If chemicals are added, the sludge produced may be different from a biological sludge and will increase the sludge volume produced. Thus, the nature of the solids produced may vary considerably and therefore necessitate different treatment scenarios prior to ultimate disposition.

The choices for the ultimate disposition of sludge are few and consist of some type of land application, incineration, or reuse. Incineration leaves a residue that must be disposed of, and concern exists regarding air-quality impacts. Thus, the ultimate residing place of the solids produced in wastewater treatment is into/onto the land or some other reuse alternative.

The objectives of the processes used to treat sludge prior to its final disposition are to reduce the volume, destroy pathogens, remove water, improve efficiency of subsequent processes, control putrescibility, and stabilize organics. Because the final product must be transported to its ultimate disposal or reuse site, attainment of these objectives will reduce transportation costs and minimize adverse environmental/public health effects. As indicated by Figure 9 , the sequence of unit processes for residuals management typically includes thickening, stabilization, dewatering, and ultimate disposal or reuse.

Figure 9

Sequence of unit processes for residuals management.

Thickening

The primary objective of sludge thickening is to concentrate the solids, thus reducing the volume of sludge. Thickeners may increase the solids concentration by a factor of 2–5 and produce a clarified liquid effluent. Thickening is accomplished by either gravity or dissolved-air flotation. A gravity thickener is shown in Figure 10 . The operation of a dissolved-air flotation unit is similar to that described for pretreatment. Decanted liquid is recirculated to the treatment plant influent.

Figure 10

Gravity thickener.

(Courtesy of Link-Belt, FMC Co.)

Sludge Stabilization

Organic sludge must be stabilized before reuse or ultimate disposal except in the case of incineration. The most common method to stabilize residual solids is by aerobic or anaerobic digestion. Aerobic digestion stabilizes excess biological solids by the oxidation of cellular organic matter through endogenous metabolism. Conventional aerobic digestion employs aeration of primary and secondary clarifier underflow in one or more completely mixed aeration basins. Diffused air or surface mechanical aerators are used to provide mixing and oxygen requirements. An aeration time of 10–20 days is usually provided based on temperature. Volatile solids reduction are in the range of 30–50%, with greater than 44% being most desirable. The digested sludge can be disposed of without causing odor or other nuisance conditions. The oxygen required for aerobic digestion can be estimated as 1.4 lb of oxygen consumed for each pound of volatile suspended solids destroyed. Nitrogen and phosphorus will be released by the oxidation process and nitrification will usually occur. As the sludge age is increased in the bioreactor, more of the degradable biomass is oxidized and less will be oxidized in the aerobic digester. The digester can be used as a source of biological seed if toxicity or inhibition is observed in the secondary treatment unit.

Anaerobic fermentation or sludge digestion decomposes organic matter in the absence of molecular oxygen. In contrast to the aerobic stabilization process, anaerobic digestion produces methane and carbon dioxide from the organic material as follows:

Organics+microorganisms+nutrients→methane+C02+moremicroorganisms

The process actually has two reactions occurring: one where complex organics are hydrolyzed and fermented into simple organic acids, and a second in which the organic acids are converted to methane and carbon dioxide. Anaerobic digesters are usually operated at a temperature near 95 F, which means that heat must be supplied. Depending on the process used, detention times may vary from 10 to 60 days, and the gas composition of a well-operated digester is about 70% methane and 30% carbon dioxide. The methane gas may be used to heat the digester or to run machinery in the plant; however, any hydrogen sulfide present must be removed because of its corrosive nature. Thermophilic digestion may be employed. It occurs at temperatures between 120 and 135 F. At the higher temperatures reaction rates are greater and thus the required retention time is reduced compared to mesophilic digestion. Other reported advantages include: improved dewaterability and increased pathogen destruction. Disadvantages are high energy requirements, poorer quality supernatant, odors and less process stability.

A two-stage anaerobic digestion operation is shown schematically in Figure 11 . Note that if the gas is not utilized, it must be flared. In addition, the supernatant shown is high in BOD and solids and must be directed into the plant influent for treatment.

Figure 11

Two-stage anaerobic digester

Advantages of the process include no oxygen required, a reduction in sludge volume, methane production, inactivation of pathogens, and the production of a good soil conditioner. The major disadvantages are a high capital cost and the need for careful operation.

Sludge Dewatering

Several methods of sludge dewatering are available, depending on the size of the plant, the kind of sludge, and site-specific considerations.

A commonly employed unit process for dewatering thickened municipal and industrial sludge is the belt filter press. As shown in Figure 12 , chemically conditioned sludge is fed through two filter belts and is squeezed by force to drive water through these belts. Chemical polymers are required to promote flocculation and enhance dewatering. A final solids concentration range of from 20 to 35% can be expected depending on the characteristics of the sludge and the method of operation.

Figure 12

Belt filter press

The pressure filter, as shown in Figure 13 (a) and Figure 13 (b), is another alternative. The sludge is fed into the press and pressure is applied so that the filtrate passes through the cloth with the solids being retained and forming a cake on the cloth. The medium is usually precoated. The filtrate is collected in the drainage ports provided at the bottom of each press chamber. The pressure operation ceases when the filtrate flow is near zero, at which time the press is opened and the cakes released. Most municipal sludge can be dewatered to produce a cake solids of 40–50% with 225-lb in− 2 filters. Conditioning chemicals such as lime, ferric chloride, or polymers are often used to enhance dewatering and minimize cloth plugging. Fly ash and coal fines have also been employed to reduce cake compressibility, thereby enhancing dewatering but adding to the sludge volume.

Figure 13

(a) Side view of a filter press; (b) filter press cutaway view.

Several types of centrifugal dewatering are also used, where the centrifuge uses centrifugal force to enhance the sludge particle sedimentation rate and concentrate the solids. Flocculants are added with the sludge to increase removal of fines. Solid-bowl centrifuges are typically employed for dewatering to 20–35% solids. Both centrate and cake solids are continuously discharged from the machine. The centrate must be returned to the plant influent for treatment.

Sludge drying beds are often used for small sludge volumes, which drain and dry rapidly. Application is usually restricted to the more arid climates. A schematic is presented in Figure 14 . The filtrate is returned to the treatment plant. About 10–30% solids can be expected depending on specific application. With good weather, well-digested sludge may achieve as high as 45% solids concentration in 6 weeks. Covered beds have also been employed in wetter climates.

Figure 14

Sand drying beds

Other methods of sludge treatment include composting, thermal treatment, incineration, advanced alkaline stabilization, and wet oxidation. Of course, combustion methods may lead to air pollution problems and have residual ash to be disposed. It should be noted that other less utilized methods exist, and treatment may be used prior to the methods described for stabilization and/or conditioning.

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Ultimate Disposition of Solids

The quality/ultimate disposition of sludge (termed biosolids for municipal wastewater residuals) is currently governed by the USEPA through 40 CFR Part 503 of the 1987 Clean Water Act Amendments. The EPA promotes practices that provide for the beneficial use of municipal sewage sludge biosolids, while maintaining or improving environmental quality and protecting public health. These practices typically include land application of biosolids as a soil amendment or fertilizer supplement and various procedures that derive energy from biosolids or convert them to useful products.

Part 503 standards provide for a wide range of end-use possibilities for biosolids that depend on sludge characteristics and treatment methods. Processes defined as Processes to Significantly Reduce Pathogens (PSRP) generate a ‘Class B’ sludge that may be used under restricted conditions. Those biosolids processed by Processes to Further Reduce Pathogens (PFRP) are termed a ‘Class A’ sludge and can be used unrestrictedly. The term ‘Exceptional Quality’ is often used to describe a biosolids product which meets Class A requirements. The end product must be stable (i.e., no odors, no vector attraction), noninfectious, and of sufficiently low metals content so as not to translocate and bioaccumulate to undesirable levels. Some treatment technologies capable of producing a Class A sludge include composting, heat drying, auto-thermal thermophilic aerobic digestion, pasteurization and gamma radiation.

The constraints on the use of sludge for growing edible crops are primarily associated with the presence of heavy metals, the nitrogen content, and the possibility of the presence of phytotoxic materials in the sludge. Particular care must be given if the solids contain contributions from industry.

Some metals of concern include arsenic, mercury, lead, zinc, copper, and nickel, although the limiting metal is usually cadmium. Cadmium is of particular concern because of its potential translocation from the soil to the fruit and the ability of certain crops, such as chard, to accumulate significant quantities in the edible portion of the plant. Other metals such as arsenic may also be accumulated in fruit and grain to levels exceeding FDA and other regulatory limits.

Nitrogenous material is also of concern and may be a limiting factor in sludge application rates. Because soil biochemical reactions are mostly aerobic, nitrification will occur, and if the nitrogen is not used by the crops, it will be converted to nitrate. Nitrate in groundwater can cause methemoglobinemia in infants.

The helminths may pose a pathogen threat because they concentrate in the sludge and possess the ability to survive extremely adverse environments. For example, Ascaris ova have been found to survive for as long as 7 years. Other pathogens may cause restrictions on crops grown in sludge application sites.

Groundwater is of primary concern in areas where sludge is applied and potential adverse effects must be considered. The travel of various contaminants through soil depends on many factors, including the soil composition, the contaminant, its concentration and speciation, and the groundwater hydrology.

As previously indicated, when biosolids are effectively treated and recycled they can be used as a significant resource. Reduced disposal volume conserves land disposal facility capacity. Other benefits include improved soil fertility and tilth, reduced need for fertilizers, better growth and quality of crops, and decreased energy consumption. According to the USEPA Biosolids Fact Sheet for Land Application of Biosolids in 2000, nationally about 60% of biosolids were land applied. In California it was 70% and in Oregon 95%. Stabilized biosolids have also been employed as intermediate and final landfill cover; to recover lands devastated by mining; and, smelting activities, and for wetlands reclamation.

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Advanced Wastewater (Tertiary) Treatment

Thus far, the conventional treatment of wastewaters has been described (BCT), and one may conclude that organic waste materials (BOD), suspended solids, and bacteria can be reduced with relatively high efficiency, as shown in Table II . The treatment plant flow scheme may be arranged as shown in Figure. 15(a) (activated sludge) or Figure 15(b) (trickling filtration). Considering the concepts previously discussed, one can trace the flow and removal of the three parameters of primary concern (BOD, suspended solids, and the bacterium Escherichia coli) by conventional treatment.

Table II

Efficiencies of treatment processes for domestic sewage

TreatmentBOD (%)Suspended solids (%)Escherichia coli (%)Plain sedimentation25–4040–7025–75Chemical precipitation50–8570–9040–80High-rate trickling filtration preceded and followed by plain sedimentation65–9565–9280–95Low-rate trickling filtration preceded and followed by plain sedimentation80–9570–9290–95High-rate activated sludge preceded and followed by plain sedimentation65–9565–9580–95Conventional activated sludge preceded and followed by plain sedimentation75–9585–9590–98Chlorination of biologically treated sewage––98–99

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Figure 15

Flow schemes for conventional municipal wastewater treatment

Other contaminants may not be significantly reduced using secondary treatment and therefore must be subjected to other removal techniques or tertiary treatment (BATEA). These contaminants include toxic organics, VOCs, phosphorus, nitrogen, heavy metals, refractory organics, and difficult-to-remove pathogens such as Giardia lamblia. Some processes investigated and applied with success for removals include coagulation and flocculation, filtration, ion exchange, nitrification, denitrification, membrane processes, air stripping, adsorption, and chemical oxidation. These will be discussed briefly in the following sections.

Suspended Solids Removal

Total Suspended solids (TSS) removal by tertiary treatment implies the removal of those materials that have been carried over from a secondary clarification process. Pretreatment is required prior to physical chemical treatment processes. Influent suspended solids concentration must be less than about 100 mg l− 1 or backwashing requirements become excessive for sand filtration. Finely dispensed suspended solids may require the addition of coagulant prior to filtration. Several means for removal of suspended solids have been proposed and tested. These include the use of diatomaceous earth filtration, pressure filtration, chemical clarification, sand filtration with conventional and multimedia units, ultrafiltration, and the moving-bed filter. With the exception of the chemical clarification processes, these methods all involve removal by physical straining of the finely divided solids.

Diatomaceous earth filtration is a form of mechanical separation that uses diatomaceous earth, a powdered filter aid, that is built up on a supporting medium. As filtration proceeds, the solid material that will not pass through the diatomaceous earth is retained and eventually builds up a pressure that will no longer allow filtration. At that point, the unit is backwashed and made ready for another cycle. It should be noted that the diatomaceous earth filtration process was developed during World War II to remove the cysts that cause amoebic dysentery and is presently quite common in swimming pool filtration.

Chemical clarification consists of four phases: coagulation, flocculation, sedimentation, and filtration. Coagulation, essentially the addition of chemicals that are rapidly mixed with the water, usually involves the use of polymers and/or the oxides of aluminum, iron, or calcium. Once the coagulation step (charge neutralization) is accomplished, the flocculation process then allows aggregation, neutralization, and adsorption of the floc particles. This process is followed by the sedimentation process, where the flocs that have been previously formed are allowed to settle. Although most of the flocculated material will be removed in the sedimentation tank, it is usually required to further remove the floc particles that do not settle by the use of a filtration process that is conducted in beds of porous media such as sand.

The usual means of filtration has been through sand beds containing graded sand placed on a supporting medium containing an underdrain to collect the filtered effluent. As wastewater containing solids is passed through this type of filter, the solids will accumulate and eventually clog up the openings causing high head loss and/or poor effluent quality. Thus, some provision must be made to remove the collected material. The procedure usually followed is to backwash the sand, that is, to reverse the flow, usually with air scour, so that the sand is suspended and the lighter material is washed away. It should be noted that subsequent to a backwashing operation, the sand will settle according to size and thus become stratified, with the smaller particles at the top. Since these particles will filter out most of the solid material, it may be concluded that the entire depth of a sand bed is not utilized in a filtration process. To alleviate this problem, a multimedia filter is employed, involving different filtration materials, each having a different specific gravity. Materials commonly used are sand, coal, and garnet, as shown in Figure. 16 . This type of filter extends the length of the filtration runs and demonstrates high efficiency. Filter loadings are usually designed from 2 to 6 gpm/ft2 with 4 gpm/ft2 being the most typical.

Figure 16

Stratification of different types of filters. (a) The activated sludge process; (b) the trickling filtration process.

The moving-bed filter is a technique that is essentially a form of countercurrent extraction, that is, feeding the sand countercurrent to the filtering water. As the filter surface becomes clogged, the filter medium is moved forward and a new surface is exposed. It is said that, theoretically, 1% of the filter is being backwashed 100% of the time as compared to a conventional backwashing operation where 100% of the filter is backwashed 1% of the time.

Ultrafiltration or nanofiltration uses pressure to drive a liquid through a membrane permeable to some consituents including fine particles, viruses, bacteria and protozoans. This process is similar to reverse osmosis, but differs with respect to the size of the particles that are separated. Ultrafiltration will generally not retain a particle whose weight is 500–1000 times the molecular weight, and thus it fails to separate inorganic salts. The pressures used in ultrafiltration are on the order of 50 lb/in2 as contrasted to pressures exceeding 500 lb/in2 in reverse osmosis. The process is essentially one of pressure filtration, using semipermeable membranes that act as molecular screens and separate colloidal and molecular materials that are dissolved or suspended in the liquid phase.

Organic Removal

As previously indicated, wastewaters may contain measurable amounts of refractory soluble organics, toxics, VOCs and other contaminants not removed by conventional processes. These problem organics may be removed at the source (usually recommended), within the biological treatment step, and/or in the tertiary treatment stage following conventional treatment. The composition of refractory organics is not always precisely known. Although they are not easily biologically oxidizable, they may exercise a BOD in a receiving water over time. In addition, these materials may cause taste and odor problems in a water supply, and more important, the potential toxicological effects on the aquatic environment and on humans have not been precisely delineated. Toxics are of concern and must be removed or reduced to below threshold concentrations prior to biological treatment. VOCs may result in noncompliance with air regulations and result in worker and public health concerns.

Volatile organics (benzene, toluene, etc.) should be removed by pretreatment prior to biological treatment. Air stripping or steam stripping can be used depending on the characteristics of the volatile organics. Air stripping is accomplished in packed or tray towers with countercurrent air–liquid flow. The off gas must be treated through vapor-phase carbon, biofilters, combustion or other methods. Steam stripping introduces steam in a packed tower, causing volatiles to be removed in the vapor phase. Biofilters can also be employed to treat off-gases from the stripper and/or aeration basin. This low-cost method employs a porous medium that promotes sorption into a liquid film on the medium surface followed by microbial stabilization. Powdered activated carbon (PAC) has been used in the aeration basin to adsorb VOCs and toxic compounds.

Chemical oxidation is typically employed to treat contaminants that may be non-biodegradable (refractory), toxic or inhibitory to microbial growth, and odor causing. Oxidizing agents used include ozone, O3; hydrogen peroxide, H2 O 2; permanganate, MnO− 4; various chlorine compounds; or even oxygen. These reactions frequently require catalysts to be cost effective. Such catalysts include UV light for ozone and hydrogen peroxide. Ferrous iron (FeSO4 or Fenton's reagent) at pH of about 3.5 is frequently employed for use with H2O2. Metal oxides such as titanium dioxide have also been employed for O3 catalysis. Ozone and UV plus various catalysts may be combined for specific waste in advanced oxidation processes. It is often not cost effective to carry the chemical oxidation to completion. Partial oxidation to compounds may be sufficient to render specific compounds such as many priority pollutants less toxic and more amenable to subsequent and less expensive biological treatment.

Adsorption may also be used to remove toxics, refractory organics, some heavy metals, and VOCs. Activated carbon possesses the property of attracting many contaminants to adhere to its surface via adsorption. Activated carbon is very porous with a very high surface-area-to-unit-weight ratio and thus possesses a high adsorption capacity for the hydrophobic soluble organics in wastewater. It can be contacted with wastewater either as a very fine powder or as granules. Since the powdered form is not conducive to column operation, granular activated carbon is used most frequently in advanced wastewater treatment plants. As the wastewater passes through the bed and the constituents from the wastewater are adsorbed onto the carbon, the sites available for adsorption will be exhausted and the bed must be replaced. The replacement can either be by new activated carbon material or by thermal regeneration of the exhausted bed. The sorption capacity of regenerated carbon however may be reduced as compared to the virgin material. In large plants, regeneration by high temperatures is usually practiced. Powdered activated carbon (PAC) can be added to the activated sludge process for enhanced performance (the PACT process). This has been shown effective for removing many priority pollutants and refractory organics. It can also remove color and enhance nitrification.

Inorganic Removal

Many of the inorganic constituents of a water will be at a higher than desirable concentration in a secondary treatment plant effluent. Although in most cases these excessive concentrations will not be harmful, continuous reuse of the water will cause a rapid buildup to prohibitive levels. Thus, a means of removing inorganics via a tertiary treatment process may be necessary. Pretreatment may also be needed to remove inorganics such as heavy metals, which may cause toxicity/inhibition to the biological treatment process. In many cases source treatment allows for reuse.

Ion exchange is a process that has been used for many years in the removal of hardness from water and of specific ions such as certain metals. The process takes advantage of the ability of certain natural and synthetic materials to exchange an ion contained in the material for another contained in the water passing through it. For example, if water containing calcium ions is passed through an ion-exchange medium that preferred calcium ions instead of the sodium ions that were already attached to it, the calcium ions will adhere to the exchange medium and the sodium ions would pass out into the effluent. The higher valence, higher molecular weight constituents replace the lesser ones. As with adsorption on carbon, if a solution containing an ion to be removed is continuously applied to the ion-exchange medium, the medium will eventually become exhausted. It may then be subjected to a process called regeneration, where the exchange medium is converted back to its original state by passing a concentrated solution of the original replaced ion through it. There are many modifications and combinations of ion-exchange units that have been used in both water and wastewater treatment technology. It should be noted that it is possible to recover material from an ion-exchange unit that might be economically advantageous. The use of ion-exchange media probably most familiar to the layman is the device that can be placed on the faucet in the home to obtain soft water for steam irons and other uses.

The electrodialysis process is used for demineralizing wastewaters. The principle of the process is shown in Figure. 17 . When voltage is applied across a cell containing mineralized water, the negatively charged ions (anions) will migrate to the positive electrode and the positively charged ions (cations) will migrate to the negative electrode. As shown in the diagram, alternate placement of anion and cation permeable membranes causes alternate compartments to become more concentrated in salts while others become more dilute. It should be noted that both suspended solids and dissolved organics should be eliminated from the feed water to the electrodialysis unit because of the possibilities of plugging and fouling. Like ion exchange, this process can be used for pretreatment of heavy metals. Note that for both ion exchange regeneration and electrodialysis concentrate wastes are produced which require proper treatment and management.

Figure 17

Electrodialysis unit. A, anion-permeable membrane; C, cation-permeable membrane.

Theoretically, the process of reverse osmosis (RO) is capable of removing greater than 90% of certain inorganic ions, organic material, and colloids. The principle involved is shown in Figure. 18 , which demonstrates various osmotic systems leading to the reverse osmosis process, and in Figure. 19 , which shows the construction of a spiral-wound reverse osmotic module. In operation, the water containing the dissolved materials is placed in contact with the membrane at a pressure in excess of the osmotic pressure of the solution. Under these conditions, the water will permeate the membrane and concentrate the dissolved materials. Problems with the reverse osmosis process have primarily been with the membranes because they are subject to fouling. Increasing effluent quality standards and the growing need for reuse of water resources has resulted in increased research, development, and implementation of RO technologies. As with ion exchange and electrodialysis processes a concentrated waste is generated which must be properly managed.

Figure 18

Principle of reverse osmosis: pressure on an osmotic system leads to reverse osmosis

Figure 19

A spiral-wound reverse osmosis module.

Nitrogen Removal

As previously mentioned, the presence of the various forms of nitrogen in water can lead to several problems, including eutrophication, oxygen demand in a receiving water, toxicity (ammonia at high pH), and methemoglobinemia in infants. The removal of nitrogen is quickly becoming an integral part of a tertiary or modified secondary treatment facility. Successful removal of ammonia nitrogen has been accomplished by raising the pH to about 10 and removing the converted ammonia by aeration. The pH is usually raised by the use of lime and a packed tower is used for the gas-stripping operation. Nitrogen can also be removed by selective ion exchange, where ammonium ion is removed by using clinoptilolite, a naturally occurring medium.

The biological process used for nitrogen removal is attained by modifying the activated sludge process to allow for the oxidation of organic nitrogen to nitrate and then subsequently denitrifying the nitrate by placing it under anoxic conditions where bacteria convert the nitrate to nitrogen gas. Both of these processes have been used successfully. However, the bacteria involved are highly sensitive to temperature and to toxic organics. Appropriate consideration must therefore be given accordingly. The conversion of ammonia nitrogen to nitrate is called nitrification, and nitrate to nitrogen gas conversion is called denitrification. The microorganisms involved for nitrification are the autotrophic genera Nitrosomonas and Nitrobacter. The growth rates of these bacteria are very slow, and hence sludge age must be sufficiently long to prevent their washout. The microbes responsible for denitrification are heterotrophic, and hence organic carbon must be available for their metabolism. The biological processes involved are shown in Figure. 20 . The same reactions occur in surface waters and ground waters. The Bardenpho process and other modifications stage anoxic and aerobic sequencing basins with significant internal recycle. Nitrification occurs in the aerobic reactor and denitrification in the anoxic basin.

Figure 20

Nitrogen transformations under aerobic conditions.

Phosphorus Removal

Because of its ability to stimulate biological growth, phosphorus in wastewater effluents is limited to very low levels whenever the receiving water discharges into a lake or impoundment. The major source of phosphorus in domestic wastewater is detergents. This has been reduced in the United States and provinces in Canada where phosphates have been controlled in detergents.

Phosphorus removal can be accomplished by chemical precipitation and by a modification of biological oxidation referred to as ‘luxury uptake.’ This involves an anaerobic step in the presence of volatile fatty acids (mainly acetic) in which P is released into solution and acetate absorbed by specialized microbes called Acinetobacter. An aerobic step follows in which P is rapidly taken up by the microbes. Phosphorous levels less than 1 mg l− 1 and often less than 0.1 mg l− 1 can be achieved by this method for municipal wastewaters. Activated sludge has also been shown to remove significant phosphorus, especially when aluminum or iron salts are added at the end of the aeration tank or before the clarifier.

MBRs have successfully been used to enhance both nitrogen and phosphorus removals. An initial anaerobic basin followed by anoxic and aerobic zones using membrane separation of mixed liquor suspended solids has been shown effective in reducing these nutrients to very low levels.

Chemical removal of phosphorus can also be accomplished with aluminum, iron, or lime. The methodology for its addition varies depending on the particular plant. Lime precipitation of phosphorus is accomplished at pH levels above 10.5. Alum can be added prior to filtration. Note that the precipitation of phosphorus will increase sludge production. Phosphorous resources are becoming limiting, hence reclamation is becoming more important in regards to sustainability goals.

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Water Reuse

It can be concluded from the previous discussion that wastewater can be treated to any quality desired and, therefore, reused, provided cost is not a controlling factor. The degree of treatment should be based on the quality requirements of the intended use of the water. Thus, if the wastewater can be used in a beneficial manner without causing adverse environmental or health effects, it should be considered as a valuable resource and used accordingly.

Drivers for water reuse vary from region to region and the nature of the application. Many years ago, there was no compelling business reason for water reuse. Non stringent regulatory requirements for the treatment and discharge of wastewater to the environment and abundance of good quality water supplies provided little incentive to water users to do anything but wastewater. Nowadays, water reuse is driven by more than a moral obligation to preserve this valuable resource. It has become good business practice by many industries and municipalities and the only option to sustain life in small to large communities in many parts of the world. Drivers such as water scarcity and droughts, lack of good quality water supplies, the cost of treating wastewater to very high standards due to more stringent regulations, permitting requirements, public relations, energy conservation, etc. have become strong motivators for industry and communities to look at wastewater as a resource not a waste.

The force field diagram shown in Figure 21 illustrates the various drivers and motivators for water reuse.

Figure 21

Water Reuse Motivatorsa

a Taken from Industrial Wastewater Management- A Systems Approach, American Institute of Chemical Engineers July 2003, 2–6.

Perhaps one of the most compelling drivers for water conservation and reuse is the scarcity of water supplies and the uneven distribution of water resources across the globe. The ever increase in population growth will undoubtedly place extreme pressures on the world conventional water supplies (fresh surface water and groundwater) and energy resources required to tap into unconventional supplies (brackish and sea water). In areas such as the Middle East, water scarcity is an everyday concern. In the Gulf Cooperation Council (GCC) countries, there are virtually no rivers, little precipitation, and limited renewable fresh groundwater supplies. Dependence on desalination is high and is extremely energy intensive and expensive. Water reuse in these countries is an everyday practice. GCC countries lead many others in the world in the reuse of their treated sewage effluent (TSE) for landscape irrigation.

Introduction

Using wastewaters in a beneficial manner is not a new concept. In fact, water reuse has been practiced for many years. Because of the many discharges into our waterways, unless one lives in the backwaters of a mountain stream, the drinking water supply contains some wastewater. Even the Romans recognized that some waters were not suitable for drinking and had separate water for drinking and another supply for other purposes. Today, this practice is called a dual water system and is used in several locations in the United States and globally as well.

Probably the most widespread reuse of wastewaters has been for agricultural purposes, i.e., applying wastewater discharges after varying degrees of treatment, or in some cases, no treatment, for irrigation of crops. Subsequent to the advent of sewerage collection systems, numerous disposal sites existed throughout the world by the early 1900s. These were called sewage farms and were primarily used for disposal, although some of the wastewater was used for crop production and other beneficial uses. One of the more notable of these sewage farms was at Melbourne, Australia, which was started in 1893 and was still operating in the 1980s.

As water shortages became acute and the cost of wastewater treatment increased, many locations started investigating the potential for reusing wastewater for nonpotable purposes, thus alleviating some of the demand for potable water and giving an alternative to additional wastewater treatment. For example, in 1929, the city of Pomona, California, started a project using reclaimed wastewater for landscape and garden irrigation; in 1932, Golden Gate Park in San Francisco started using water from an on-site activated sludge plant for landscape irrigation and for small lakes in the park.

Probably the first introduction of treated wastewater into a municipal groundwater source was at Whittier Narrows in California in 1962, and direct injection of reclaimed wastewater into a groundwater aquifer was started in Orange County, California, in 1976. Although the primary purpose of the Orange County injection is to prevent saltwater intrusion, a high percentage of the reclaimed wastewater enters an aquifer used as a drinking-water source.

The use of dual distribution systems should also be mentioned inasmuch as, where feasible, a dual system significantly reduces potable water demand by using one system for potable water and the other for irrigation and other uses not requiring potable water. Notable of these systems is one installed in 1960 in Colorado Springs, Colorado, which supplies reclaimed water in a separate system for landscape irrigation. St. Petersburg, Florida, installed a similar system in 1977 where reclaimed water is supplied via a 260-mile dual system for irrigation of public parks, landscape irrigation, golf courses, and cooling-tower makeup water. It is interesting to note that although the initial impetus for the system was pollution abatement, the greatest benefit has been in water conservation by significantly reducing potable water demand.

The first direct potable water reuse project in the world was at Windhoek, Namibia. Here highly treated wastewater is introduced directly into the potable water reservoir/ distribution system. During drought periods, the reclaimed water is as much as 30% of the supply. This project was started in 1960 and was expanded in 2000.

As the world's population increases and the number of people living in urban centers grows, the need for water is becoming increasingly acute, particularly in semiarid and arid areas and when droughts occur. In many locations, especially under drought conditions, the demand for water exceeds the supply. Thus, there is no doubt that reclaimed water will play a major role in the water supply of the future. Many reuse programs in the arid and semiarid United States have been instigated by a need for water; however, many reuse projects have also been instigated in order to avoid costly compliance with requirements for wastewater discharges into surface waters. These requirements usually involve nitrogen and phosphorus removal and concomitant advanced wastewater treatment. It should be noted that these nutrients may actually be of benefit in agricultural water reuse and in wetlands enhancement.

It is significant to note that the major uses of water do not require potable water quality. Industry, for instance, uses significantly large volumes of water for cooling, processing, steam production, and other general uses. The majority of that water evaporates (evaporative cooling) or leaves the site with the product. However, a good portion remains and ends up as process water requiring disposal. Industry, depending on geographic location, also has to address storm water runoff and discharge, particularly when it becomes contaminated with raw materials, product, by products, or other industrial operations.

Industry is driven more and more towards water conservation, recycling, and reuse as public, media, and regulatory scrutiny regarding how industry sources, treats, and manages water continues to increase. Companies who treat water and wastewater as a commodity do so at great risk. Others who value water and wastewater as a precious resource have a greater chance of sustaining their operations and improving their viability in the market place.

From the perspective of industrial water users, water reuse can be approached from different angles. One such approach is to conserve water and reuse effluent within the fence of their operation. Traditionally, the industry has made strides in the design and operation of processes to minimize water use and optimize reuse through practices such as segregation of clean and contaminated streams, cascading water reuse (where the quality of the effluent discharged from one process is good enough to be used in another before treatment or disposal is required), and reuse of their wastewater effluent for cooling operations, fire fighting, and wash water requirements.

A second approach is for industry to look outside the fence of their operation for water conservation and reuse opportunities. An example would be to address water management throughout their entire supply chain from production, transportation, logistics, reprocessing of intermediate products by others, to final product use. Another outside the fence approach, which is gaining favor in countries such as Saudi Arabia and is driving the establishment of an entire infrastructure to support it, is the reuse of municipal effluent for industrial applications such as industrial cooling, mining, district cooling, etc. The success of such an approach greatly depends on realizing the true value of treating water without considering government subsidies as is the case in some countries.

Wastewater Contaminants Inimical to Reuse

Municipal and industrial wastewaters can contain anything that is contributed to the sewer as attributed by day to day human activities and the specific industrial manufacturing processes. Therefore, constraints on the use of the wastewater may be imposed by its chemical, biological, and physical characteristics. Consideration of potential adverse effects of these many parameters on public health and/or the environment is mandatory. The presence of some contaminants may preclude use of the water for some purposes if their removal is not economical. An economic analysis of the cost of treating and delivering the wastewater as compared to the benefits of its beneficial use must be made. This may include costs of advanced wastewater treatment that could be negated by avoiding discharge into a water-quality-limited waterbody. Parameters of concern are as follows.

Inorganic Chemicals

The list of inorganic chemicals that could be present in a wastewater is all inclusive. Many inorganic ions are naturally found in water such as calcium, sodium, magnesium, potassium, bicarbonates, chlorides, sulfates, and nitrates. Wastewaters may contain these ions and many others which may be contributed by a myriad of sources. The presence of some ions, such as boron, may totally preclude the use of a wastewater for irrigation because of its toxicity to plants. Also, the potential bioaccumulation and toxicity of the heavy metals to plants, humans and animals must be considered along with other potentially harmful materials. Selected drinking and irrigation standards are shown in Table III . It should be noted that because of pretreatment standards imposed on industrial waste discharges to municipal sewers in the U.S., the presence of many of these materials is being minimized. As previously noted, advanced wastewater treatment can remove these ions to acceptable levels.

Table III

Selected drinking and irrigation water standards (mg l− 1)a

ConstituentDrinking waterFor fine-textured soilsFor any soilFor livestockAluminum205Arsenic0.0120.10.2Barium1.0Boron0.7525.0Cadmium0.010.050.010.05Chromium0.051.00.11.0Copper1.050.20.5Iron0.3205Lead0.051050.1Manganese0.05100.02Mercury0.0020.01Nickel2.00.2Selenium0.010.020.020.05Zinc510225

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aTaken from http://water.epa.gov/lawsregs/rulesregs/sdwa/regulations.cfm

Organic Chemicals

Listing the organic chemicals that may be in municipal and industrial wastewater is difficult if not impossible, primarily because of the numerous species existing, some of which may be formed by interactions with each other. Many organics are relatively new and the long-term health effects are unknown, as are potential synergistic effects (e.g., endocrine disrupters and pharmaceuticals and personal care products). Although drinking-water standards exist for some organics, compliance does not guarantee that the water is safe for potable use. Furthermore, the traditional measures of organics, such as BOD, COD, and TOC, reveal little concerning the toxicity and health effects of the organics measured. It should be noted that organics such as pesticides, insecticides, and herbicides may be found in any drinking-water source where runoff contributes to the waterbody. Numerous organics have been detected in water and wastewater at very low levels; however, many remain unidentified. Even with advances in analytical techniques, technology, and epidemiological studies, it cannot be concluded that many of these trace organics found in wastewater do not pose a potential health hazard.

Microbiological Considerations

Protection from waterborne disease is paramount, both in drinking-water supplies and in recreational waters. Pathogenic microorganisms found in wastewater may include bacteria, viruses, protozoans, algae, and helminths. The major waterborne pathogenic microorganisms that have been found in the United States are tabulated in Table IV

Table IV

Major waterborne pathogens and related disease

PathogenDiseaseBacteriaShigella (spp.)Shigellosis (bacillary dysentery)Salmonella typhiTyphoid feverSalmonella (1700 serotypes spp.)SalmonellosisVibro choleraeCholeraEscherichia coli (enteropathogenic)Gastroenteritis and septicemia, hemolytic uremic svndrome (HUS)Yersinia enterocoliticaYersiniosisLeptospira (spp.)LeptospirosisCampylobacter jejuneGastroenteritis, reactive arthritisProtozoaEntamoeba histolyticaAmebiasis (amebic dysentery)Giardia lambliaGiardiasis (gastroenteritis)CryptosporidiumCryptosporidiosis, diarrhea, feverMicrosporidiaDiarrheaHelminthsAscaris lumbricoidesAscariasis (roundworm infection)Ancylostoma (spp)Ancylostomiasis (hookworm infection)Necator americanusNecatoriasis (roundworm infection)Ancylostoma (spp.)Cutaneous larva migrams (hookworm infection)Strongloides stercoralisStrongyloidiasis (threadworm infection)Trichuris trichiuraTrichuriasis (whipworm infection)Taenia (spp.)Taeniasis (tapeworm infection)Enterobius vermicularisEnterobiasis (pinwork infection)Echinococcus granulosus (spp.)Hydatidosis (tapeworm infection)VirusesEnteroviruses (polio, echo, coxsackie, new enteroviruses, serotype 68–71)Gastroenteritis, heart anomolies, meningitis, othersHepatitis A and E virusinfectious hepatitisAdenovirusRespiratory disease eye infectons, gastroenteritis (serotype 40 and 41)RotavirusGastroenteritisParvovirusGastroenteritisNorovirusesDiarrhea, vomiting, feverAstrovirusGastroenteritisCalicivirusGastroenteritisCoronavirusGastroenteritis

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Adapted from National Research Council, 1996; Sagik et. al., 1978; and Hurst et. al., 1989

The presence of these microorganisms, which clearly exist in untreated wastewater, are of obvious public health concern, and every effort must be made to minimize the possibility of human contact when using reclaimed wastewater for any purpose. As previously discussed, conventional wastewater treatment can reduce the levels of these pathogens to acceptable concentrations, although advanced wastewater treatment may be required for indirect potable reuse. Bacteria are most susceptible to conventional treatment when adequate disinfection is included. Viruses and protozoans are more difficult to remove and may require additional treatment, such as ultrafiltration and reverse osmosis. The protozoans, such as giardia and cryptosporidium, are much more resistant and may survive even high concentrations of chlorine.

Serious outbreaks of giardiasis and cryptosporidiosis have occurred in cities with excellent water-treatment facilities and are of major concern in the water industry. Therefore, every effort must be made to minimize human contact with reclaimed water that may contain any of these pathogens. Of particular concern is the possibility of pathogens being carried in aerosols emitted by spray irrigation inasmuch as aerosols in the 2–5 mm size are primarily removed in the respiratory tract. Notably, there are no documented reports of disease outbreaks attributed to spray irrigation with disinfected reclaimed wastewater. The potential transmission of Legionnaires' disease (Legionella) by drift from cooling towers should also be noted.

Survival of pathogens depends on several factors, including temperature, soil organic content, humidity, solar radiation, and foliage. Typical survival times are shown in Table V .

Table V

Typical Pathogen survival times at 20–30 °C. (in days) d

PathogenSurvival Time (days)

Fresh Water & SewageCropsSoilVirusesaEnterovirusesb< 120 but usually < 50< 60 but usually < 15< 100 but usually < 20BacteriaFecal conforms a,c< 60 but usually < 30< 30 but usually < 15< 70 but usually < 20Salmonella spp.a< 60 but usually < 30< 30 but usually < 15< 70 but usually < 20Shigella spp.a< 30 but usually < 10< 10 but usually < 5---Vibrio choleraed< 30 but usually < 10< 5 but usually < 2< 20 but usually < 10ProtozoaEntamoeba histolytica cysts< 30 but usually < 15< 10 but usually < 2< 20 but usually < 10HelminthsAscaris lumbricoides eggsMany months< 60 but usually < 30Many months

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aIn seawater, viral survival is less, and bacterial survival is very much less than in fresh water.

bIncludes polio, echo-, and Coxsackie viruses.

cV. cholerae survival in aqueous environments is uncertain.

dTaken from USEPA Guidelines for Water Reuse, 2004 (http://nepis.epa.gov/Adobe/PDF/30006MKD.pdf).

Adapted from Feacham et. al., 1983

Hence the use of reclaimed wastewater may pose some risks with respect to potential exposure to microorganisms. However, with good design and operation, proper monitoring, and appropriate precautions maintained, the risk from any reclaimed water application is minimal. According to the Water Environment Federation, water reuse has not been implicated as the cause in any infectious disease outbreak.

Other Water Quality Parameters of Concern

The presence of excessive solids can cause problems in the distribution system by settling out in the system and by clogging the nozzles in spray irrigation. They can also cause problems when reclaimed water is applied to soils by clogging the soils and reducing the infiltration rate. Also, some solids adsorb heavy metals and solids can also shield microorganisms from disinfection.

Excessive salinity may have a profound effect on both plants and soils. It is usually measured by electroconductivity, which is related to total dissolved solids (TDS). As salts infiltrate into the ground, they tend to concentrate in the root zone because of evapotranspiration (evaporation from soil and surface water and transpiration) by plants. With an increase in salinity, plants expend energy in adjusting for osmotic effects to obtain water from the soil. Thus, less energy is available for plant growth and a reduction in productivity occurs. Adequate drainage is mandatory for long-term use of reclaimed water for irrigation, and it may be necessary to leach more water through the soil than the plants require in order to maintain a proper salt balance.

Sodium is of particular concern in irrigation water because of its ability to cause changes in soil structure, infiltration, and permeability rates. A high percentage of sodium in a soil with some clays causes conditions unfavorable for water movement and plant growth. The hazard from sodium can be estimated by its ratio to calcium and magnesium, and methods are available to determine its effect on soils and plants.

Nutrients important to plants include nitrogen, phosphorus, potassium, zinc, boron, and sulfur, all of which may be present in wastewater. The most beneficial nutrient in reclaimed water is nitrogen, which may replace an equal amount of nitrogen in fertilizer during the growing period. However, nitrogen in excessive amounts may be detrimental to crops and monitoring may be required. It should also be noted that under aerobic conditions, nitrogen in the wastewater existing as organic or ammonia nitrogen will ultimately be converted to nitrate, of concern because of its relationship to methemoglobinemia.

Applications of Water Reuse

As previously indicated, water is becoming a scarce resource and the use of reclaimed water for many purposes is receiving increasing attention. Possible uses of reclaimed water and potential restraints are shown in Table VI .

Table VI

Categories of Waste water Reuse and Potential Constraints a, b

Waste water reuse categoriesPotential constraints1. Agricultural irrigation
Crop irrigation
Commercial nurseries

• •

  Surface and groundwater pollution if not properly managed

• •

  Marketability of crops and public acceptance

• •

  Public health concerns related to pathogens (bacteria, viruses, parasites)

• •

  Effect of water quality, particularly on soils & crops

2. Landscape irrigation
Parks
Schoolyards
Freeway medians
Golf courses
Cemeteries
Greenbelts
Residential

• •

  Public health concerns related to pathogens

• •

  Use area control including buffer zone; may result in high user cost

3. Industrial recycling and reuse
Cooling
Boiler feed
Process water
Heavy construction

• •

  Constituents in waste water related to scaling, corrosion biological growth, and fouling

• •

  Cross connection potable and reclaimed water lines

• •

  Public health concerns, particularly aerosol transmission of pathogens in cooling water

4. Groundwater recharge
Groundwater replenishment
Salt water intrusion control
Subsidence control

• •

  Organic chemicals in reclaimed waste water and their toxicological effects

• •

  Possible contamination of groundwater aquifer used as a source of potable water

• •

  Total dissolved solids, nitrates, and pathogens in reclaimed wastewater

5. Recreational/environmental uses
Lakes and ponds
Marsh enhancement
Streamflow augmentation
Fisheries
Snowmaking

• •

  Health concerns related to presence of bacteria,viruses and other pathogens (e.g., enteric infections and ear, eye and nose infections)

• •

  Eutrophication due to P and N in receiving water

• •

  Toxicity to aquatic life

6. Nonpotable urban uses
Fire protection
Air conditioning
Toilet flushing

• •

  Public health concerns on pathogen transmitted by aerosols

• •

  Effects of water quality on scaling, corrosion, biological growth, and fouling

• •

  Cross connections of potable and reclaimed water lines

7. Potable reuse

• •

  Constituents in reclaimed water, especially trace organic chemicals and their toxicological effects

• •

  Health concern regarding pathogen transmission

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aTaken from Waste water Engineering, Metcalf and Eddy, McGraw-Hill, 2003.

bArranged in descending order of projected volume of use.

Thus a wide spectrum of applications for reclaimed water exists, and each use has special concerns and requirements for treating the wastewater that helps to ameliorate these concerns. More cities, in particular those in arid, semiarid, and water-short areas, will increase their interest in water reuse. It is unlikely that direct potable reuse will be common in the near future; however, as is the case in Namibia, where no other source is available, pipe-to-pipe use is possible with no apparent adverse effects. One only has to consider the many wastewater discharges into the Mississippi River and the use of that waterbody as a drinking water source for New Orleans to conclude that indirect potable reuse is viable. Advanced wastewater treatment can produce almost any water quality desired and has become more reliable and effective through experience and innovation.

With regards to planned indirect potable reuse, the National Resources Council stated in 1998 that any community considering potable reuse should do so only after a careful, thorough, site-specific assessment that includes contaminant monitoring, health and safety testing, and system reliability evaluation.

It is instructive to examine several successful water-reuse projects to illustrate the viability and utility of wastewater reuse and its potential in helping to solve critical water shortages.

St. Petersburg Dual Water System

Dual water systems have the capability of minimizing the use of potable water inasmuch as non-potable water is used is used for purposes not requiring potable water. This reduces the demand for potable water and its concomitant cost of treatment. The use of dual water systems is much more attractive when developing new systems, when the cost of constructing another distribution system can be minimized, as was the case in St. Petersburg. The St. Petersburg system, which has been in operation since 1977, uses 20 MGD of reclaimed water via 260 miles of distribution piping. The reclaimed water is used for parks, golf courses, industrial processes, commercial uses, and residences. The St. Petersburg dual water system approach has allowed the city to meet the demand from a 10% population increase without increasing supplies. When excess reclaimed water exists, forty million gallons of treated wastewater can be stored onsite; after that the reclaimed water is pumped into a saltwater aquifer some 900 ft below the ground surface.

The Orange County, California, Groundwater Replenishment System

At Orange County, CA groundwater discharge with direct injection of reclaimed wastewater has been practiced since 1976. The original plant treated 15 MGD of activated sludge effluent using, reverse osmosis to treat part of the effluent to satisfy a 500 mg l− 1 TDS maximum requirement because of limitations imposed. The water was then injected into four aquifers to form a seawater intrusion barrier. Before injection, the water was blended 2:1 with well water from a deep non-contaminated aquifer. The water could then flow to the ocean or to augment the potable water supply, or in both directions. The water produced from the treatment plant had no measurable viruses, non-detectable coliform organisms, and an average turbidity of 0.22 TU. Continuing monitoring showed the treatment process removed potential contaminants to non-detect levels for drinking water. Epidemiological studies showed no measurable adverse health effects in the populations ingesting the reclaimed water. It must be recognized that the reclaimed water was diluted with non-contaminated water and had time in the aquifer for natural purification. This facility was recently demolished to make room for a new Groundwater Replenishment (GWR) system. The system opened in 2008 at a cost of $480 million to build and $29 million a year to operate. This enhancement was necessary due to increased population growth, salt water intrusion due to over pumping from the ground water aquifer, the on going chronic drought, and the increased cost of importing water from Northern California. The treatment train consist of filter screens followed by microfiltration. Reverse osmosis is next and the effluent is disinfected using UV light with hydrogen peroxide, About 70 MGD of water is produced. Approximately half filters through the soil into deep aquifers. The rest is injected into the Orange County seawater barrier to prevent ocean seawater intrusion.

The Tahoe-Truckee Sanitation District

This advanced 9.6 MGD wastewater treatment plant, which is located near Lake Tahoe, California, is probably the longest-operating sophisticated plant in the world. This treatment process consist of screening, grit removal, sedimentation, activated sludge, biological phosphorous removal, chemical treatment, filtration, ion exchange ammonia removal and chlorination for disinfection. A unique system of ammonia removal is employed. A combination of ion exchange using clinoptilolite (a natural ion-exchange medium) in conjunction with an indoor air stripping operation results in the recovery of ammonium sulfate, a fertilizer. The effluent has better water quality than many municipal drinking waters. In spite of the high degree of treatment, the effluent is injected into the groundwater system via a leach field where it eventually finds its way into the Truckee River, which is the major source of water for Reno, Nevada.

Regulations for Water Reuse

There are presently no existing federal standards for water reclamation and reuse. However, several states have adopted applicable regulations, and as the need for water becomes more critical, more stringent state regulations will undoubtedly be promulgated. Arizona, California, Colorado, Florida, Hawaii, Nevada, Oregon, and Texas have adopted regulations that encourage water reuse. Some states have based their regulations on providing an alternative to surface water discharge. In states with no regulations, reuse may be permitted on a case-by-case basis. It should also be noted that many foreign countries have pertinent regulations and the World Health Organization has published guidelines for water reuse.

The prime objective of existing regulations is to protect public health and the major consideration has been for irrigation; however, little attention has been given to the potential adverse effects of some constituents of wastewater on plants and soil. As previously mentioned, these effects can be profound and should be considered. The regulations address the following categories of reuse with appropriate restrictions and requirements (taken from Guidelines for Water Reuse, USEPA, 2004)

• 1.

  Unrestricted urban reuse. Irrigation in areas in which public access is not restricted, such as parks, playgrounds, school yards and residences, toilet flushing, fire fighting, air conditioning, construction, ornamental fountains, and aesthetic impoundments.

• 2.

  Restricted urban reuse. Irrigation of areas in which public access can be controlled, such as golf courses, cemeteries, and highway medians.

• 3.

  Agricultural reuse on food crops. Irrigation of food crops that are intended for direct human consumption, often further classified as to whether the food crop is to be processed or consumed raw.

• 4.

  Agricultural reuse on nonfood crops. Irrigation of fodder, fiber and seed crops, pastureland, commercial nurseries, and sod farms.

• 5.

  Unrestricted recreational use. An impoundment of water in which no limitations are imposed on body-contact water-recreation activities.

• 6.

  Restricted recreational reuse. An impoundment of reclaimed water in which recreation is limited to fishing, boating, and other noncontact recreational activities.

• 7.

  Environmental reuse. Reclaimed water used to create artificial wetlands, to enhance natural wetlands, and to sustain stream flows.

• 8.

  Industrial reuse. Reclaimed water used in industrial facilities primarily for cooling system makeup water, boiler feed water, process water, and general washdown.

Requirements may include water quality and treatment, monitoring, system reliability, storage for system or excess reclaimed water, application rates, groundwater monitoring, and setback or buffer zones. The most restrictive regulations are for indirect potable use via groundwater recharge by surface spreading or direct injection and augmentation of surface supplies. An important consideration in indirect potable reuse is public perception. Several projects have been rejected because of public and/or political pressure, health concerns being the major reasons for rejection. These categories of reuse and pertinent restrictions have been further refined and expanded by USEPA Guidelines for Water Reuse, 2012.

Finally, the question of water rights must be investigated. While states east of the Mississippi use the Riparian Rights Doctrine, states west of the Mississippi use the Doctrine of Prior Appropriation. In Western water-short areas, water rights may play a major role in any water resource project.

Abstract

Water scarcity is one of the major problems in the world and millions of people have no access to freshwater. Untreated wastewater is widely used for agriculture in many countries. This is one of the world-leading serious environmental and public health concerns. Instead of using untreated wastewater, treated wastewater has been found more applicable and ecofriendly option. Moreover, environmental toxicity due to solid waste exposures is also one of the leading health concerns. Therefore, intending to combat the problems associated with the use of untreated wastewater, we propose in this review a multidisciplinary approach to handle wastewater as a potential resource for use in agriculture. We propose a model showing the efficient methods for wastewater treatment and the utilization of solid wastes in fertilizers. The study also points out the associated health concern for farmers, who are working in wastewater-irrigated fields along with the harmful effects of untreated wastewater. The consumption of crop irrigated by wastewater has leading health implications also discussed in this review paper. This review further reveals that our current understanding of the wastewater treatment and use in agriculture with addressing advancements in treatment methods has great future possibilities.

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1 Introduction

Rapidly depleting and elevating the level of freshwater demand, though wastewater reclamation or reuse is one of the most important necessities of the current scenario. Total water consumption worldwide for agriculture accounts 92% (Clemmens et al., 2008; Hoekstra & Mekonnen, 2012; Tanji & Kielen, 2002). Out of which about 70% of freshwater is used for irrigation (WRI, 2020), which comes from the rivers and underground water sources (Pedrero et al., 2010). The statistics shows serious concern for the countries facing water crisis. Shen et al. (2014) reported that 40% of the global population is situated in heavy water–stressed basins, which represents the water crisis for irrigation. Therefore, wastewater reuse in agriculture is an ideal resource to replace freshwater use in agriculture (Contreras et al., 2017). Treated wastewater is generally applied for non-potable purposes, like agriculture, land, irrigation, groundwater recharge, golf course irrigation, vehicle washing, toilet flushes, firefighting, and building construction activities. It can also be used for cooling purposes in thermal power plants (Katsoyiannis et al., 2017; Mohsen, 2004; Smith, 1995; Yang et al., 2017). At global level, treated wastewater irrigation supports agricultural yield and the livelihoods of millions of smallholder farmers (Sato et al., 2013). Global reuse of treated wastewater for agricultural purposes shows wide variability ranging from 1.5 to 6.6% (Sato et al., 2013; Ungureanu et al., 2018). More than 10% of the global population consumes agriculture-based products, which are cultivated by wastewater irrigation (WHO, 2006). Treated wastewater reuse has experienced very rapid growth and the volumes have been increased ~10 to 29% per year in Europe, the USA, China, and up to 41% in Australia (Aziz & Farissi, 2014). China stands out as the leading country in Asia for the reuse of wastewater with an estimated 1.3 M ha area including Vietnam, India, and Pakistan (Zhang & Shen, 2017). Presently, it has been estimated that, only 37.6% of the urban wastewater in India is getting treated (Singh et al., 2019). By utilizing 90% of reclaimed water, Israel is the largest user of treated wastewater for agriculture land irrigation (Angelakis & Snyder, 2015). The detail information related to the utilization of freshwater and treated wastewater is compiled in Table 1.

Table 1 Freshwater and treated wastewater utilization status in different countries

Full size table

Many low-income countries in Africa, Asia, and Latin America use untreated wastewater as a source of irrigation (Jiménez & Asano, 2008). On the other hand, middle-income countries, such as Tunisia, Jordan, and Saudi Arabia, use treated wastewater for irrigation (Al-Nakshabandi et al., 1997; Balkhair, 2016a; Balkhair, 2016b; Qadir et al., 2010; Sato et al., 2013).

Domestic water and treated wastewater contains various type of nutrients such as phosphorus, nitrogen, potassium, and sulfur, but the major amount of nitrogen and phosphorous available in wastewater can be easily accumulated by the plants, that’s why it is widely used for the irrigation (Drechsel et al., 2010; Duncan, 2009; Poustie et al., 2020; Sengupta et al., 2015). The rich availability of nutrients in reclaimed wastewater reduces the use of fertilizers, increases crop productivity, improves soil fertility, and at the same time, it may also decrease the cost of crop production (Chen et al., 2013a; Jeong et al., 2016). The data of high nutritional values in treated wastewater is shown in Fig. 1.

Fig. 1

Nutrient concentrations (mg/L) of freshwater/wastewater (Yadav et al., 2002)

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Wastewater reuse for crop irrigation showed several health concerns (Ungureanu et al., 2020). Irrigation with the industrial wastewater either directly or mixing with domestic water showed higher risk (Chen et al., 2013). Risk factors are higher due to heavy metal and pathogens contamination because heavy metals are non-biodegradable and have a long biological half-life (Chaoua et al., 2019; WHO, 2006). It contains several toxic elements, i.e., Cu, Cr, Mn, Fe, Pb, Zn, and Ni (Mahfooz et al., 2020). These heavy metals accumulate in topsoil (at a depth of 20 cm) and sourcing through plant roots; they enter the human and animal body through leafy vegetables consumption and inhalation of contaminated soils (Mahmood et al., 2014). Therefore, health risk assessment of such wastewater irrigation is important especially in adults (Mehmood et al., 2019; Njuguna et al., 2019; Xiao et al., 2017). For this, an advanced wastewater treatment method should be applied before release of wastewater in the river, agriculture land, and soils. Therefore, this review also proposed an advance wastewater treatment model, which has been tasted partially at laboratory scale by Kesari and Behari (2008), Kesari et al. (2011a, b), and Kumar et al. (2010).

For a decade, reuse of wastewater has also become one of the global health concerns linking to public health and the environment (Dang et al., 2019; Narain et al., 2020). The World Health Organization (WHO) drafted guidelines in 1973 to protect the public health by facilitating the conditions for the use of wastewater and excreta in agriculture and aquaculture (WHO, 1973). Later in 2005, the initial guidelines were drafted in the absence of epidemiological studies with minimal risk approach (Carr, 2005). Although, Adegoke et al. (2018) reviewed the epidemiological shreds of evidence and health risks associated with reuse of wastewater for irrigation. Wastewater or graywater reuse has adverse health risks associated with microbial hazards (i.e., infectious pathogens) and chemicals or pharmaceuticals exposures (Adegoke et al., 2016; Adegoke et al., 2017; Busgang et al., 2018; Marcussen et al., 2007; Panthi et al., 2019). Researchers have reported that the exposure to wastewater may cause infectious (helminth infection) diseases, which are linked to anemia and impaired physical and cognitive development (Amoah et al., 2018; Bos et al., 2010; Pham-Duc et al., 2014; WHO, 2006).

Owing to an increasing population and a growing imbalance in the demand and supply of water, the use of wastewater has been expected to increase in the coming years (World Bank, 2010). The use of treated wastewater in developed nations follows strict rules and regulations. However, the direct use of untreated wastewater without any sound regulatory policies is evident in developing nations, which leads to serious environmental and public health concerns (Dickin et al., 2016). Because of these issues, we present in this review, a brief discussion on the risk associated with the untreated wastewater exposures and advanced methods for its treatment, reuse possibilities of the treated wastewater in agriculture.

2 Environmental Toxicity of Untreated Wastewater

Treated wastewater carries larger applicability such as irrigation, groundwater recharge, toilet flushing, and firefighting. Municipal wastewater treatment plants (WWTPs) are the major collection point for the different toxic elements, pathogenic microorganisms, and heavy metals. It collects wastewater from divergent sources like household sewage, industrial, clinical or hospital wastewater, and urban runoff (Soni et al., 2020). Alghobar et al. (2014) reported that grass and crops irrigated with sewage and treated wastewater are rich in heavy metals in comparison with groundwater (GW) irrigation. Although, heavy metals classified as toxic elements and listed as cadmium, lead, mercury, copper, and iron. An exceeding dose or exposures of these heavy metals could be hazardous for health (Duan et al., 2017) and ecological risks (Tytła, 2019). The major sources of these heavy metals come from drinking water. This might be due to the release of wastewater into river or through soil contamination reaches to ground water. Table 2 presenting the permissible limits of heavy metals presented in drinking water and its impact on human health after an exceeding the amount in drinking water, along with the route of exposure of heavy metals to human body.

Table 2 Total permissible limits of heavy metals in drinking water and diseases associated with the surplus amount

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Direct release in river or reuse of wastewater for irrigation purposes may create short-term implications like heavy metal and microbial contamination and pathogenic interaction in soil and crops. It has also long-term influence like soil salinity, which grows with regular use of untreated wastewater (Smith, 1995). Improper use of wastewater for irrigation makes it unsafe and environment threatening. Irrigation with several different types of wastewater, i.e., industrial effluents, municipal and agricultural wastewaters, and sewage liquid sludge transfers the heavy metals to the soil, which leads to accumulation in crops due to improper practices. This has been identified as a significant route of heavy metals into aquatic resources (Agoro et al., 2020). Hussain et al. (2019) investigated the concentration of heavy metals (except for Cd) was higher in the soil irrigated with treated wastewater (large-scale sewage treatment plant) than the normal ground water, also reported by Khaskhoussy et al. (2015).

In other words, irrigation with wastewater mitigates the quality of crops and enhances health risks. Excess amount of copper causes anemia, liver and kidney damage, vomiting, headache, and nausea in children (Bent & Bohm, 1995; Madsen et al., 1990; Salem et al., 2000). A higher concentration of arsenic may lead to bone and kidney cancer (Jarup, 2003) and results in osteopenia or osteoporosis (Puzas et al., 2004). Cadmium gives rise to musculoskeletal diseases (Fukushima et al., 1970), whereas mercury directly affects the nervous system (Azevedo et al., 2014).

3 Spread of Antibiotic Resistance

Currently, antibiotics are highly used for human disease treatment; however, uses in poultries, animal husbandries, biochemical industries, and agriculture are common practices these days. Extensive use and/or misuse of antibiotics have given rise to multi-resistant bacteria, which carry multiple resistance genes (Icgen & Yilmaz, 2014; Lv et al., 2015; Tripathi & Tripathi, 2017; Xu et al., 2017). These multidrug-resistant bacteria discharged through the sewage network and get collected into the wastewater treatment plants. Therefore, it can be inferred that the WWTPs serve as the hotspot of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Though, these antibiotic-resistant bacteria can be disseminated to the different bacterial species through the mobile genetic elements and horizontal gene transfer (Gupta et al., 2018). Previous studies indicated that certain pathogens might survive in wastewater, even during and after the treatment processes, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) (Börjesson et al., 2009; Caplin et al., 2008). The use of treated wastewater in irrigation provides favorable conditions for the growth and persistence of total coliforms and fecal coliforms (Akponikpe et al., 2011; Sacks & Bernstein, 2011). Furthermore, few studies have also reported the presence of various bacterial pathogens, such as Clostridium, Salmonella, Streptococci, Viruses, Protozoa, and Helminths in crops irrigated with treated wastewater (Carey et al., 2004; Mañas et al., 2009; Samie et al., 2009). Goldstein (2013) investigated the survival of ARB in secondary treated wastewater and proved that it causes serious health risks to the individuals, who are exposed to reclaimed water. The U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) have already declared the ARBs as the imminent hazard to human health. According to the list published by WHO, regarding the development of new antimicrobial agents, the ESKAPE (Enterococcus faecium, S. aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens were designated to be “priority status” as their occurrence in the food chain is considered as the potential and major threat for the human health (Tacconelli et al., 2018).

These ESKAPE pathogens have acquired the multi drug resistance mechanisms against oxazolidinones, lipopeptides, macrolides, fluoroquinolones, tetracyclines, β-lactams, β-lactam–β-lactamase inhibitor combinations, and even those antibiotics that are considered as the last line of defense, including carbapenems and glycopeptides (Giddins et al., 2017; Herc et al., 2017; Iguchi et al., 2016; Naylor et al., 2018; Zaman et al., 2017), by the means of genetic mutation and mobile genetic elements. These cluster of ESKAPE pathogens are mainly responsible for lethal nosocomial infections (Founou et al., 2017; Santajit & Indrawattana, 2016).

Due to the wide application of antibiotics in animal husbandry and inefficient capability of wastewater treatment plants, the multidrug-resistant bacteria such as tetracyclines, sulfonamides, β-lactam, aminoglycoside, colistin, and vancomycin in major are disseminated in the receiving water bodies, which ultimately results in the accumulation of ARGs in the irrigated crops (He et al., 2020).

4 Toxic Contaminations in Wastewater Impacting Human Health

The release of untreated wastewater into the river may pose serious health implications (König et al., 2017; Odigie, 2014; Westcot, 1997). It has been already discussed about the household and municipal sewage which contains a major amount of organic materials and pathogenic microorganisms and these infectious microorganisms are capable of spreading various diseases like typhoid, dysentery, diarrhea, vomiting, and malabsorption (Jia & Zhang, 2020; Numberger et al., 2019; Soni et al., 2020). Additionally, pharmaceutical industries also play a key role in the regulation and discharge of biologically toxic agents. The untreated wastewater also contains a group of contaminants, which are toxic to humans. These toxic contaminations have been classified into two major groups: (i) chemical contamination and (ii) microbial contamination.

4.1 Chemical Contamination

Mostly, various types of chemical compounds released from industries, tanneries, workshops, irrigated lands, and household wastewaters are responsible for several diseases. These contaminants can be organic materials, hydrocarbons, volatile compounds, pesticides, and heavy metals. Exposure to such contaminants may cause infectious diseases like chronic dermatoses and skin cancer, lung infection, and eye irritation. Most of them are non-biodegradable and intractable. Therefore, they can persist in the water bodies for a very long period and could be easily accumulated in our food chain system. Several pharmaceutical personal care products (PPCPs) and surfactants are available that may contain toxic compounds like nonylphenol, estrone, estradiol, and ethinylestradiol. These compounds are endocrine-disrupting chemicals (Bolong et al., 2009), and the existence of these compounds in the human body even in the trace amounts can be highly hazardous. Also, the occurrence of perfluorinated compounds (PFCs) in wastewater, which is toxic in nature, has been significantly reported worldwide (Templeton et al., 2009). Furthermore, PFCs cause severe health menaces like pre-eclampsia, birth defects, reduced human fertility (Webster, 2010), immunotoxicity (Dewitt et al., 2012), neurotoxicity (Lee & Viberg, 2013), and carcinogenesis (Bonefeld-Jorgensen et al., 2011).

4.2 Microbial Contamination

Researchers have reported serious health risks associated with the microbial contaminants in untreated wastewater. The diverse group of microorganisms causes severe health implications like campylobacteriosis, diarrhea, encephalitis, typhoid, giardiasis, hepatitis A, poliomyelitis, salmonellosis, and gastroenteritis (ISDH, 2009; Okoh et al., 2010). Few bacterial species like P. aeruginosa, Salmonella typhimurium, Vibrio cholerae, G. intestinales, Legionella spp., E. coli, Shigella sonnei have been reported for the spreading of waterborne diseases, and acute illness in human being (Craun et al., 2006; Craun et al., 2010). These aforementioned microorganisms may release in the environment from municipal sewage water network, animal husbandries, or hospitals and enter the food chain via public water supply systems.

5 Wastewater Impact on Agriculture

The agriculture sector is well known for the largest user of water, accounting for nearly 70% of global water usage (Winpenny et al., 2010). The fact that an estimated 20 million hectares worldwide are irrigated with wastewater suggests a major source for irrigation (Ecosse, 2001). However, maximum wastewater that is used for irrigation is untreated (Jiménez & Asano, 2008; Scott et al., 2004). Mostly in developing countries, partially treated or untreated wastewater is used for irrigation purpose (Scott et al., 2009). Untreated wastewater often contains a large range of chemical contaminants from waste sites, chemical wastes from industrial discharges, heavy metals, fertilizers, textile, leather, paper, sewage waste, food processing waste, and pesticides. World Health Organization (WHO) has warned significant health implications due to the direct use of wastewater for irrigation purposes (WHO, 2006). These contaminants pose health risks to communities (farmers, agricultural workers, their families, and the consumers of wastewater-irrigated crops) living in the proximity of wastewater sources and areas irrigated with untreated wastewater (Qadir et al., 2010). Wastewater also contains a wide variety of organic compounds. Some of them are toxic or cancer-causing and have harmful effects on an embryo (Jarup, 2003; Shakir et al., 2016). The pathway of untreated wastewater used in irrigation and associated health effects are shown in Fig. 2.

Fig. 2

Exposure pathway representing serious health concerns from wastewater-irrigated crops

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Alternatively, in developing countries, due to the limited availability of treatment facilities, untreated wastewater is discharged into the existing waterbodies (Qadir et al., 2010). The direct use of wastewater in agriculture or irrigation obstructs the growth of natural plants and grasses, which in turn causes the loss of biodiversity. Shuval et al. (1985) reported one of the earliest evidences connecting to agricultural wastewater reuse with the occurrence of diseases. Application of untreated wastewater in irrigation increases soil salinity, land sealing followed by sodium accumulation, which results in soil erosion. Increased soil salinity and sodium accumulation deteriorates the soil and decreases the soil permeability, which inhibits the nutrients intake of crops from the soil. These causes have been considered the long-term impact of wastewater reuse in agriculture (Halliwell et al., 2001). Moreover, wastewater contaminated soils are a major source of intestinal parasites (helminths—nematodes and tapeworms) that are transmitted through the fecal–oral route (Toze, 1997). Already known, the helminth infections are linked to blood deficiency and behavioral or cognitive development (Bos et al., 2010). One of the major sources of helminth infections around the world is the use of raw or partially treated sewage effluent and sludge for the irrigation of food crops (WHO, 1989). Wastewater-irrigated crops contain heavy metal contamination, which originates from mining, foundries, and metal-based industries (Fazeli et al., 1998). Exposure to heavy metals including arsenic, cadmium, lead, and mercury in wastewater-irrigated crops is a cause for various health problems. For example, the consumption of high amounts of cadmium causes osteoporosis in humans (Dickin et al., 2016). The uptake of heavy metals by the rice crop irrigated with untreated effluent from a paper mill has been reported to cause serious health concerns (Fazeli et al., 1998). Irrigating rice paddies with highly contaminated water containing heavy metals leads to the outbreak of Itai-itai disease in Japan (Jarup, 2003).

Owing to these widespread health risks, the WHO published the third edition of its guidelines for the safe use of wastewater in irrigating crops (WHO, 2006) and made recommendations for threshold contaminant levels in wastewater. The quality of wastewater for agricultural reuse have been classified based on the availability of nutrients, trace elements, microorganisms, and chemicals contamination levels. The level of contamination differs widely depending on the type of source, household sewage, pharmaceutical, chemical, paper, or textile industries effluents. The standard measures of water quality for irrigation are internationally reported (CCREM, 1987; FAO, 1985; FEPA, 1991; US EPA, 2004, 2012; WHO, 2006), where the recommended levels of trace elements, metals, COD, BOD, nitrogen, and phosphorus are set at certain limits. Researchers reviewed the status of wastewater reuse for agriculture, based on its standards and guidelines for water quality (Angelakis et al., 1999; Brissaud, 2008; Kalavrouziotis et al., 2015). Based on these recommendations and guidelines, it is evident that greater awareness is required for the treatment of wastewater safely.

6 Wastewater Treatment Techniques

6.1 Primary Treatment

This initial step is designed to remove gross, suspended and floating solids from raw wastewater. It includes screening to trap solid objects and sedimentation by gravity to remove suspended solids. This physical solid/liquid separation is a mechanical process, although chemicals can be used sometimes to accelerate the sedimentation process. This phase of the treatment reduces the BOD of the incoming wastewater by 20–30% and the total suspended solids by nearly 50–60%.

6.2 Secondary (Biological) Treatment

This stage helps eliminate the dissolved organic matter that escapes primary treatment. Microbes consume the organic matter as food, and converting it to carbondioxide, water, and energy for their own growth. Additional settling to remove more of the suspended solids then follows the biological process. Nearly 85% of the suspended solids and biological oxygen demand (BOD) can be removed with secondary treatment. This process also removes carbonaceous pollutants that settle down in the secondary settling tank, thus separating the biological sludge from the clear water. This sludge can be fed as a co-substrate with other wastes in a biogas plant to obtain biogas, a mixture of CH4 and CO2. It generates heat and electricity for further energy distribution. The leftover, clear water is then processed for nitrification or denitrification for the removal of carbon and nitrogen. Furthermore, the water is passed through a sedimentation basin for treatment with chlorine. At this stage, the water may still contain several types of microbial, chemical, and metal contaminations. Therefore, to make the water reusable, e.g., for irrigation, it further needs to pass through filtration and then into a disinfection tank. Here, sodium hypochlorite is used to disinfect the wastewater. After this process, the treated water is considered safe to use for irrigation purposes. Solid wastes generated during primary and secondary treatment processes are processed further in the gravity-thickening tank under a continuous supply of air. The solid waste is then passed into a centrifuge dewatering tank and finally to a lime stabilization tank. Treated solid waste is obtained at this stage and it can be processed further for several uses such as landfilling, fertilizers and as a building.

Other than the activated sludge process of wastewater treatment, there are several other methods developed and being used in full-scale reactors such as ponds (aerobic, anaerobic, facultative, and maturation), trickling filters, anaerobic treatments like up-flow anaerobic sludge blanket (UASB) reactors, artificial wetlands, microbial fuel cells, and methanogenic reactors.

UASB reactors are being applied for wastewater treatment from a very long period. Behling et al. (1996) examined the performance of the UASB reactor without any external heat supply. In their study, the COD loading rate was maintained at 1.21 kg COD/m3/day, after 200 days of trial. They achieved an average of 85% of COD removal. Von-Sperling and Chernicharo (2005) presented a combined model consisted of an Up-flow Anaerobic Sludge Blanket-Activated Sludge reactor (UASB–AS system), using the low strength domestic wastewater with a BOD5 amounting to 340 mg/l. Outcomes of their experiment have shown a 60% reduction in sludge construction and a 40% reduction in aeration energy consumption. In another experiment, Rizvi et al. (2015) seeded UASB reactor with cow manure dung to treat domestic wastewater; they observed 81%, 75%, and 76% reduction in COD, TSS, and total sulfate removal, respectively, in their results.

6.3 Tertiary or Advanced Treatment Processes

The tertiary treatment process is employed when specific constituents, substances, or contaminants cannot be completely removed after the secondary treatment process. The tertiary treatment processes, therefore, ensure that nearly 99% of all impurities are removed from wastewater. To make the treated water safe for drinking purposes, water is treated individually or in combination with advanced methods like the US (ultrasonication), UV (ultraviolet light treatment), and O3 (exposure to ozone). This process helps to remove bacteria and heavy metal contaminations remaining in the treated water. For the purpose, the secondarily treated water is first made to undergo ultrasonication and it is subsequently exposed to UV light and passed through an ozone chamber for the complete removal of contaminations. The possible mechanisms by which cells are rendered inviable during the US include free-radical attack and physical disruption of cell membranes (Phull et al., 1997; Scherba et al., 1991). The combined treatment of US + UV + O3 produces free radicals, which are attached to cell membranes of the biological contaminants. Once the cell membrane is sheared, chemical oxidants can enter the cell and attack internal structures. Thus, the US alone or in combination facilitates the deagglomeration of microorganisms and increases the efficiency of other chemical disinfectants (Hua & Thompson, 2000; Kesari et al., 2011a, b; Petrier et al., 1992; Phull et al., 1997; Scherba et al., 1991). A combined treatment method was also considered by Pesoutova et al. (2011) and reported a very effective method for textile wastewater treatment. The effectiveness of ultrasound application as a pre-treatment step in combination with ultraviolet rays (Blume & Neis, 2004; Naddeo et al., 2009), or also compared it with various other combinations of both ultrasound and UV radiation with TiO2 photocatalysis (Paleologou et al., 2007), and ozone (Jyoti & Pandit, 2004) to optimize wastewater disinfection process.

An important aspect of our wastewater treatment model (Fig. 3) is that at each step of the treatment process, we recommend the measurement of the quality of treated water. After ensuring that the proper purification standards are met, the treated water can be made available for irrigation, drinking or other domestic uses.

Fig. 3

A wastewater treatment schematic highlighting the various methods that result in a progressively improved quality of the wastewater from the source to the intended use of the treated wastewater for irrigation purposes

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6.4 Nanotechnology as Tertiary Treatment of Wastewater Converting Drinking Water Alike

Considering the emerging trends of nanotechnology, nanofillers can be used as a viable method for the tertiary treatment of wastewater. Due to the very small pore size, 1–5-nm nanofillers may eliminate the organic–inorganic pollutants, heavy metals, as well as pathogenic microorganisms and pharmaceutically active compounds (PhACs) (Mohammad et al., 2015; Vergili, 2013). Over the recent years, nanofillers have been largely accepted in the textile industry for the treatment of pulp bleaching pharmaceutical industry, dairy industry, microbial elimination, and removal of heavy metals from wastewater (Abdel-Fatah, 2018). Srivastava et al. (2004) synthesized very efficient and reusable water filters from carbon nanotubes, which exhibited effective elimination of bacterial pathogens (E. coli and S. aureus), and Poliovirus sabin-1 from wastewater.

Nanofiltration requires lower operating pressure and lesser energy consumption in comparison of RO and higher rejection of organic compounds compared to UF. Therefore, it can be applied as the tertiary treatment of wastewater (Abdel-Fatah, 2018). Apart from nanofilters, there are various kinds of nanoparticles like metal nanoparticles, metal oxide nanoparticles, carbon nanotubes, graphene nanosheets, and polymer-based nanosorbents, which may play a different role in wastewater treatment based on their properties. Kocabas et al. (2012) analyzed the potential of different metal oxide nanoparticles and observed that nanopowders of TiO2, FeO3, ZnO2, and NiO can exhibit the exceeding amount of removal of arsenate from wastewater. Cadmium contamination in wastewater, which poses a serious health risk, can be overcome by using ZnO nanoparticles (Kumar & Chawla, 2014). Latterly, Vélez et al. (2016) investigated that the 70% removal of mercury from wastewater through iron oxide nanoparticles successfully performed. Sheet et al. (2014) used graphite oxide nanoparticles for the removal of nickel from wastewater. An exceeding amount of copper causes liver cirrhosis, anemia, liver, and kidney damage, which can be removed by carbon nanotubes, pyromellitic acid dianhydride (PMDA) and phenyl aminomethyl trimethoxysilane (PAMTMS) (Liu et al., 2010).

Nanomaterials are efficiently being used for microbial purification from wastewater. Carbon nanotubes (CNTs) are broadly applied for the treatment of wastewater contaminated with E. coli, Salmonella, and a wide range of microorganisms (Akasaka & Watari, 2009). In addition, silver nanoparticles reveal very effective results against the microorganisms present in wastewater. Hence, it is extensively being used for microbial elimination from wastewater (Inoue et al., 2002). Moreover, CNTs exhibit high binding affinity to bacterial cells and possess magnetic properties (Pan & Xing, 2008). Melanta (2008) confirmed and recommended the applicability of CNTs for the removal of E. coli contamination from wastewater. Mostafaii et al. (2017) suggested that the ZnO nanoparticles could be the potential antibacterial agent for the removal of total coliform bacteria from municipal wastewater. Apart from the previously mentioned, applicability of the nanotechnology, the related drawbacks and challenges cannot be neglected. Most of the nanoengineered techniques are currently either in research scale or pilot scale performing well (Gehrke et al., 2015). Nevertheless, as discussed above, nanotechnology and nanomaterials exhibit exceptional properties for the removal of contaminants and purification of water. Therefore, it can be adapted as the prominent solution for the wastewater treatment (Zekić et al., 2018) and further use for drinking purposes.

6.5 Wastewater Treatment by Using Plant Species

Some of the naturally growing plants can be a potential source for wastewater treatment as they remove pollutants and contaminants by utilizing them as a nutrient source (Zimmels et al., 2004). Application of plant species in wastewater treatment may be cost-effective, energy-saving, and provides ease of operation. At the same time, it can be used as in situ, where the wastewater is being produced (Vogelmann et al., 2016). Nizam et al. (2020) analyzed the phytoremediation efficiency of five plant species (Centella asiatica, Ipomoea aquatica, Salvinia molesta, Eichhornia crassipes, and Pistia stratiotes) and achieved the drastic decrease in the amount of three pollutants viz. total suspended solids (TSS), ammoniacal nitrogen (NH3-N), and phosphate levels. All the five species found to be efficient removal of the level of 63.9-98% of NH3-N, TSS, and phosphate. Coleman et al. (2001) examined the physiological effects of domestic wastewater treatment by three common Appalachian plant species: common rush or soft rush (Juncus effuses L.), gray club-rush (Scirpus Validus L.), and broadleaf cattail or bulrush (Typha latifolia L.). They observed in their experiments about 70% of reduction in total suspended solids (TSS) and biochemical oxygen demand (BOD), 50% to 60% of reduction in nitrogen, ammonia, and phosphate levels, and a significant reduction in feacal coliform populations. Whereas, Zamora et al. (2019) found the removal efficiency of chemical oxygen demand (COD), total solids suspended (TSS), nitrogen as ammonium (N-NH4) and nitrate (N-NO3), and phosphate (P-PO4) up to 20–60% higher using the three ornamental species of plants viz. Canna indica, Cyperus papyrus, and Hedychium coronarium. The list of various plant species applied for the wastewater treatment is shown in Table 3.

Table 3 Various plant species applied for the wastewater remediation and their effects

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6.6 Wastewater Treatment by Using Microorganisms

There is a diverse group of bacteria like Pseudomonas fluorescens, Pseudomonas putida, and different Bacillus strains, which are capable to use in biological wastewater systems. These bacteria work in the cluster forms as a floc, biofilm, or granule during the wastewater treatment. Furthermore, after the recognition of bacterial exopolysaccharides (EPS) as an efficient adsorption material, it may be applied in a revolutionary manner for the heavy metal elimination (Gupta & Diwan, 2017). There are few examples of EPS, which are commercially available, i.e., alginate (P. aeruginosa, Azotobacter vinelandii), gellan (Sphingomonas paucimobilis), hyaluronan (. aeruginosa, Pasteurella multocida, Streptococci attenuated strains), xanthan (Xanthomonas campestris), and galactopol (Pseudomonas oleovorans) (Freitas et al., 2009; Freitas, Alves, & Reis, 2011a; Freitas, Alves, Torres, et al., 2011b). Similarly, Hesnawi et al. (2014) experimented biodegradation of municipal wastewater using local and commercial bacteria (Sludge Hammer), where they achieved a significant decrease in synthetic wastewater, i.e., 70%, 54%, 52%, 42% for the Sludge Hammer, B. subtilis, B. laterosponus, and P. aeruginosa, respectively. Therefore, based on the above studies, it can be concluded that bioaugmentation of wastewater treatment reactor with selective and mixed strains can ameliorate the treatment. During recent years, microalgae have attracted the attention of researchers as an alternative system, due to their applicability in wastewater treatment. Algae are the unicellular or multicellular photosynthetic microorganism that grows on water surfaces, salt water, or moist soil. They utilize the exceeding amount of nutrients like nitrogen, phosphorus, and carbon for their growth and metabolism process through their anaerobic system. This property of algae also inhibits eutrophication; that is to avoid over-deposit of nutrients in water bodies. During the nutrient digestion process, algae produce oxygen that is constructive for the heterotrophic aerobic bacteria, which may further be utilized to degrade the organic and inorganic pollutants. Kim et al. (2014) observed a total decrease in the levels of COD (86%), total nitrogen (93%), and total phosphorus (83%) after using algae in the municipal wastewater consortium. Nmaya et al. (2017) reported the heavy metal removal efficiency of microalga Scenedesmus sp. from contaminated river water in the Melaka River, Malaysia. They observed the effective removal of Zn (97-99%) on the 3rd and 7th day of the experiment. The categorized list of microorganisms used for wastewater treatment is presented in Table 4.

Table 4 Microorganisms applied for wastewater treatment

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7 The Computational Approach in Wastewater Treatment

7.1 Bioinformatics and Genome Sequencing

A computational approach is accessible in wastewater treatment. Several tools and techniques are in use such as, sequencing platforms (Hall, 2007; Marsh, 2007), metagenome sequencing strategies (Schloss & Handelsman, 2005; Schmeisser et al., 2007; Tringe et al., 2005), bioinformatics tools and techniques (Chen & Pachter, 2005; Foerstner et al., 2006; Raes et al., 2007), and the genome analysis of complex microbial communities (Fig. 4). Most of the biological database contains microorganisms and taxonomical information. Thus, these can provide extensive details and supports for further utilization in wastewater treatment–related research and development (Siezen & Galardini, 2008). Balcom et al. (2016) explored that the microbial population residing in the plant roots immersed in the wastewater of an ecological WWTP and showed the evidence of the capacity for micro-pollutant biodegradation using whole metagenome sequencing (WMS). Similarly, Kumar et al. (2016) revealed that bioremediation of highly polluted wastewater from textile dyes by two novel strains were found to highly decolorize Joyfix Red. They were identified as Lysinibacillus sphaericus (KF032717) and Aeromonas hydrophila (KF032718) through 16S rDNA analysis. More recently, Leddy et al. (2018) reported that research scientists are making strides to advance the safety and application of potable water reuse with metagenomics for water quality analysis. The application of the bio-computational approach has also been implemented in the advancements of wastewater treatment and disease detection.

Fig. 4

A schematic showing the overall conceptual framework on which depicting the computational approach in wastewater treatment

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7.2 Computational Fluid Dynamics in Wastewater Treatment

In recent years, computational fluid dynamics (CFD), a broadly used method, has been applied to biological wastewater treatment. It has exposed the inner flow state that is the hydraulic condition of a biological reactor (Peng et al., 2014). CFD is the application of powerful predictive modeling and simulation tools. It may calculate the multiple interactions between all the water quality and process design parameters. CFD modeling tools have already been widely used in other industries, but their application in the water industry is quite recent. CFD modeling has great applications in water and wastewater treatment, where it mechanically works by using hydrodynamic and mass transfer performance of single or two-phase flow reactors (Do-Quang et al., 1998). The level of CFD’s capability varies between different process units. It has a high frequency of application in the areas of final sedimentation, activated sludge basin modeling, disinfection, and greater needs in primary sedimentation and anaerobic digestion (Samstag et al., 2016). Now, researchers are enhancing the CFD modeling with a developed 3D model of the anoxic zone to evaluate further hydrodynamic performance (Elshaw et al., 2016). The overall conceptual framework and the applications of the computational approach in wastewater treatment are presented in Fig. 4.

7.3 Computational Artificial Intelligence Approach in Wastewater Treatment

Several studies were obtained by researchers to implement computer-based artificial techniques, which provide fast and rapid automated monitoring of water quality tests such as BOD and COD. Recently, Nourani et al. (2018) explores the possibility of wastewater treatment plant by using three different kinds of artificial intelligence methods, i.e., feedforward neural network (FFNN), adaptive neuro-fuzzy inference system (ANFIS), and support vector machine (SVM). Several measurements were done in terms of effluent to tests BOD, COD, and total nitrogen in the Nicosia wastewater treatment plant (NWWTP) and reported high-performance efficiency of artificial intelligence (Nourani et al., 2018).

7.4 Remote sensing and Geographical Information System

Since the implementation of satellite technology, the initiation of new methods and tools became popular nowadays. The futuristic approach of remote sensing and GIS technology plays a crucial role in the identification and locating of the water polluted area through satellite imaginary and spatial data. GIS analysis may provide a quick and reasonable solution to develop atmospheric correction methods. Moreover, it provides a user-friendly environment, which may support complex spatial operations to get the best quality information on water quality parameters through remote sensing (Ramadas & Samantaray, 2018).

8 Applications of Treated Wastewater

8.1 Scope in Crop Irrigation

Several studies have assessed the impact of the reuse of recycled/treated wastewater in major sectors. These are agriculture, landscapes, public parks, golf course irrigation, cooling water for power plants and oil refineries, processing water for mills, plants, toilet flushing, dust control, construction activities, concrete mixing, and artificial lakes (Table 5). Although the treated wastewater after secondary treatment is adequate for reuse since the level of heavy metals in the effluent is similar to that in nature (Ayers & Westcot, 1985), experimental evidences have been found and evaluated the effects of irrigation with treated wastewater on soil fertility and chemical characteristics, where it has been concluded that secondary treated wastewater can improve soil fertility parameters (Mohammad & Mazahreh, 2003). The proposed model (Fig. 3) is tested partially previously at a laboratory scale by treating the wastewater (from sewage, sugar, and paper industry) in an ultrasonic bath (Kesari et al., 2011a, b; Kesari & Behari, 2008; Kumar et al., 2010). Advancing it with ultraviolet and ozone treatment has modified this in the proposed model. A recent study shows that the treated water passed quality measures suited for crop irrigation (Bhatnagar et al., 2016). In Fig. 3, a model is proposed including all three (UV, US, nanoparticle, and ozone) techniques, which have been tested individually as well as in combination (US and nanoparticle) (Kesari et al., 2011a, b) to obtain the highest water quality standards acceptable for irrigation and even drinking purposes.

Table 5 Applications, methods and health concerns of treated or untreated wastewater for irrigation

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A wastewater-irrigated field is a major source of essential and non-essential metals contaminants such as lead, copper, zinc, boron, cobalt, chromium, arsenic, molybdenum, and manganese. While crops need some of these, the others are non-essential metals, toxic to plants, animals, and humans. Kanwar and Sandha (2000) reported that heavy metal concentrations in plants grown in wastewater-irrigated soils were significantly higher than in plants grown in the reference soil in their study. Yaqub et al. (2012) suggest that the use of US is very effective in removing heavy or toxic metals and organic pollutants from industrial wastewater. However, it has been also observed that the metals were removed efficiently, when UV light was combined with ozone (Samarghandi et al., 2007). Ozone exposure is a potent method for the removal of metal or toxic compounds from wastewater as also reported earlier (Park et al., 2008). Application of US, UV, and O3 in combination lead to the formation of reactive oxygen species (ROS) that oxidize certain organics, metal ions and kill pathogens. In the process of advanced oxidizing process (AOP) primarily oxidants, electricity, light, catalysts etc. are implied to produce extremely reactive free radicals (such as OH) for the breakdown of organic matters (Oturan & Aaron, 2014). Among the other AOPs, ozone oxidization process is more promising and effective for the decomposition of complex organic contaminants (Xu et al., 2020). Ozone oxidizes the heavy metal to their higher oxidation state to form metallic oxides or hydroxides in which they generally form limited soluble oxides and gets precipitated, which are easy to be filtered by filtration process. Ozone oxidization found to be efficient for the removal of heavy metals like cadmium, chromium, cobalt, copper, lead, manganese, nickel, and zinc from the water source (Upadhyay & Srivastava, 2005). Ultrasonic-treated sludge leads to the disintegration of biological cells and kills bacteria in treated wastewater (Kesari, Kumar, et al., 2011a; Kesari, Verma, & Behari, 2011b). This has been found that combined treatment with ultrasound and nanoparticles is more effective (Kesari, Kumar, et al., 2011a). Ultrasonication has the physical effects of cavitation inactivate and lyse bacteria (Broekman et al., 2010). The induced effect of US, US, or ozone may destroy the pathogens and especially during ultrasound irradiation including free-radical attack, hydroxyl radical attack, and physical disruption of cell membranes (Kesari, Kumar, et al., 2011a; Phull et al., 1997; Scherba et al., 1991).

8.2 Energy and Economy Management

Municipal wastewater treatment plants play a major role in wastewater sanitation and public health protection. However, domestic wastewater has been considered as a resource or valuable products instead of waste, because it has been playing a significant role in the recovery of energy and resource for the plant-fertilizing nutrients like phosphorus and nitrogen. Use of domestic wastewater is widely accepted for the crop irrigation in agriculture and industrial consumption to avoid the water crisis. It has also been found as a source of energy through the anaerobic conversion of the organic content of wastewater into methane gas. However, most of the wastewater treatment plants are using traditional technology, as anaerobic sludge digestion to treat wastewater, which results in more consumption of energy. Therefore, through these conventional technologies, only a fraction of the energy of wastewater has been captured. In order to solve these issues, the next generation of municipal wastewater treatment plants is approaching total retrieval of the energy potential of water and nutrients, mostly nitrogen and phosphorus. These plants also play an important role in the removal and recovery of emerging pollutants and valuable products of different nature like heavy and radioactive metals, fertilizers hormones, and pharma compounds. Moreover, there are still few possibilities of improvement in wastewater treatment plants to retrieve and reuse of these compounds. There are several methods under development to convert the organic matter into bioenergy such as biohydrogen, biodiesel, bioethanol, and microbial fuel cell. These methods are capable to produce electricity from wastewater but still need an appropriate development. Energy development through wastewater is a great driver to regulate the wastewater energy because it produces 10 times more energy than chemical, thermal, and hydraulic forms. Vermicomposting can be utilized for stabilization of sludge from the wastewater treatment plant. Kesari and Jamal (2017) have reported the significant, economical, and ecofriendly role of the vermicomposting method for the conversion of solid waste materials into organic fertilizers as presented in Fig. 5. Solid waste may come from several sources of municipal and industrial sludge, for example, textile industry, paper mill, sugarcane, pulp industry, dairy, and intensively housed livestock. These solid wastes or sewage sludges have been treated successfully by composting and/or vermicomposting (Contreras-Ramos et al., 2005; Elvira et al., 1998; Fraser-Quick, 2002; Ndegwa & Thompson, 2001; Sinha et al., 2010) Although collection of solid wastes materials from sewage or wastewater and further drying is one of the important concerns, processing of dried municipal sewage sludge (Contreras-Ramos et al., 2005) and management (Ayilara et al., 2020) for vermicomposting could be possible way of generating organic fertilizers for future research. Vermicomposting of household solid wastes, agriculture wastes, or pulp and sugarcane industry wastes shows greater potential as fertilizer for higher crop yielding (Bhatnagar et al., 2016; Kesari & Jamal, 2017). The higher amount of solid waste comes from agricultural land and instead of utilizing it, this biomass is processed by burning, which causes severe diseases (Kesari & Jamal, 2017). Figure 3 shows the proper utilization of solid waste after removal from wastewater; however, Fig. 5 showing greater possibility in fertilizer conversion which has also been discussed in detail elsewhere (Bhatnagar et al., 2016; Nagavallemma et al., 2006)

Fig. 5

Energy production through wastewater (reproduced from Bhatnagar et al., 2016; Kesari & Jamal, 2017)

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9 Conclusions and future perspectives

In this paper, we have reviewed environmental and public health issues associated with the use of untreated wastewater in agriculture. We have focused on the current state of affairs concerning the wastewater treatment model and computational approach. Given the dire need for holistic approaches for cultivation, we proposed the ideas to tackle the issues related to wastewater treatment and the reuse potential of the treated water. Water resources are under threat because of the growing population. Increasing generation of wastewater (municipal, industrial, and agricultural) in developing countries especially in India and other Asian countries has the potential to serve as an alternative of freshwater resources for reuse in rice agriculture, provide appropriate treatment, and distribution measures are adopted. Wastewater treatment is one of the big challenges for many countries because increasing levels of undesired or unknown pollutants are very harmful to health as well as environment. Therefore, this review explores the ideas based on current and future research. Wastewater treatment includes very traditional methods by following primary, secondary, and tertiary treatment procedures, but the implementation of advanced techniques is always giving us a big possibility of good water quality. In this paper, we have proposed combined methods for the wastewater treatment, where the concept of the proposed model works on the various types of wastewater effluents. The proposed model not only useful for wastewater treatment but also for the utilization of solid wastes as fertilizer. An appropriate method for the treatment of wastewater and further utilization for drinking water is the main futuristic outcome. It is also highly recommendable to follow the standard methods and available guidelines provided WHO. In this paper, the proposed role of the computational model, i.e., artificial intelligence, fluid dynamics, and GIS, in wastewater treatment could be useful in future studies. In this review, health concerns associated with wastewater irrigation for farmers and irrigated crops consumers have been discussed.

The crisis of freshwater is one of the growing concerns in the twenty-first century. Globaly, about 330 km3 of municipal wastewater is generated annually (Hernández-Sancho et al., 2015). This data provides a better understanding of why the reuse of treated wastewater is important to solve the issues of the water crisis. The use of treated wastewater (industrial or municipal wastewater or Seawater) for irrigation has a better future for the fulfillment of water demand. Currently, in developing countries, farmers are using wastewater directly for irrigation, which may cause several health issues for both farmers and consumers (crops or vegetables). Therefore, it is very imperative to implement standard and advanced methods for wastewater treatment. A local assessment of the environmental and health impacts of wastewater irrigation is required because most of the developed and developing countries are not using the proper guidelines. Therefore, it is highly required to establish concrete policies and practices to encourage safe water reuse to take advantage of all its potential benefits in agriculture and for farmers.

Wastewater treatment involves the extraction of pollutants, removal of coarse particles, and elimination of toxicants. Moreover, wastewater treatment kills pathogens and produces bio-methane and fresh manure for agricultural production. The connection between waste management and sustainability created the basis for this research. Wastewater treatment is part of the efforts to minimize water waste, minimize pressure on natural sources of water, and create a pathway for clean energy. A systematic literature review was selected for this study to evaluate and synthesize the available evidence in support of wastewater treatment for both economic and environmental sustainability. The articles were evaluated using the PRISMA framework to identify the most appropriate articles for inclusion. A total of 46 articles were selected based on their content validity, relevance to the research question, strength of evidence, year of publication (2000–2023), and relevance to sustainable resource management. The findings indicate that wastewater treatment enables sustainable resource management by improving the supply of clean water, and minimizing pressure on natural resources, energy recovery, and agricultural support. Wastewater treatment provides one of the most sustainable approaches to water conservation, energy production, and agricultural productivity.

Keywords:

environmental sustainability; economic sustainability; sustainable resource management; wastewater treatment

1. Introduction

Background and Scope of Study

The main objective of wastewater treatment is to extract pollutants, remove coarse particles, eliminate toxicants, and kill potential pathogens so that the remaining clean water, known as effluent, can be discharged back into the environment to meet various purposes [1,2]. World Vision estimates that more than 770 million people around the world have no access to clean and safe water for drinking and domestic use [2]. Wastewater treatment is also aimed at making more water available for use and reducing pressure on natural water resources [2,3]. As water scarcity intensifies with increased demand and encroaching drought conditions, wastewater treatment becomes one of the most viable options for enhancing water sustainability [3]. Al-Juaidi et al. [4] believe that the growing human population will continue to exert more pressure on natural resources, including clean water, for domestic and industrial use. Without a sustainable source of water, the world risks facing acute water shortages and diseases associated with polluted water.

Water scarcity is both a natural and man-made problem. More than 700 million people around the world are currently living in countries or regions with a chronic shortage of water [3,4,5]. The United Nations Water (UN Water) estimates that the number of those who face water scarcity will increase to about 1.8 billion people by 2025 [6,7]. The growing threat of climate change is also pushing more than 50% of the global population to live in areas where they face significant water shortages [5,7,8]. Regions in sub-Saharan Africa are more likely to be affected because they currently account for the largest number of water-stressed countries in the world [9,10]. The United Nations also estimates that between 70 million and 250 million people will face acute water shortages in Africa [5,9,11]. Taking early measures, including wastewater treatment, may help in reversing the catastrophic effects of living without clean and safe water for drinking, agriculture, or industrial use.

Much of the wastewater comes from homes, industries, and businesses. In homes, water from sinks, showers, bathtubs, dishwashers, toilets, and washing machines is often channeled through collection pipes to sewage treatment plants [10,11,12]. Industrial processes such as manufacturing and cooling often produce wastewater that may contain chemicals and solid particles [9]. Businesses such as hotels and restaurants also produce significant amounts of wastewater that should be cleaned and made available for the next use. According to Villarín and Merel [2], water treatment is often designed to meet “fit-for-purpose specifications” for the selected next use. The “fit-for-purpose specifications” are the requirements that must be met to protect the public and the environment from the potential hazards associated with wastewater [8,13,14,15]. Untreated or polluted water may expose consumers to various public health challenges, including cholera outbreaks, dysentery, and typhoid [10,11,16]. When discharged into lakes and oceans, the decaying organic matter and debris in wastewater can use up the dissolved oxygen that fish and other aquatic life need to survive.

Although wastewater treatment has received significant research attention, its connection to sustainable resource management has not been adequately addressed. Most of the current literature has focused on the various techniques of wastewater treatment, touching very little on sustainability [14]. Some of the common wastewater treatment techniques discussed in the previous studies include chemical treatment, physical treatment, the use of biological organisms, and sludge treatment [17]. Previous studies have also explored basic steps in wastewater treatment, including screening and pumping (preliminary treatment), primary treatment, secondary treatment, disinfection, and sludge treatment [12,18,19,20,21,22]. However, the processes in wastewater treatment largely depend on the intended use. According to Libhaber et al. [23], the focus on sustainability ensures that there is sufficient clean water to meet the needs of the current generation without compromising the ability of future generations to obtain the same commodity. Although water remains one of the most abundant natural resources on the planet, accessibility is always limited [16,18,24]. Those who live in arid and semi-arid areas have poor access to clean and sustainable water.

The qualitative hypothesis for this research is that “wastewater treatment leads to sustainable water resource management”. This indicates that wastewater treatment ensures there is sufficient water to meet people’s needs while protecting natural resources from potential depletion. This study examines the extent to which wastewater treatment generates sustainable use and management of water resources. The research intends to test this hypothesis using evidence obtained from various studies. The test will also examine the extent to which wastewater treatment techniques enhance sustainability. The qualitative variables, in this case, include “sustainable outcomes of wastewater treatment” and “wastewater treatment techniques”.

The overarching purpose of this study is to evaluate and synthesize the available evidence in support of wastewater treatment for both economic and environmental sustainability. The paper focuses on the need for wastewater treatment and how it contributes to sustainable water resource management. The paper will also analyze the various wastewater treatment methods and their levels of sustainability. The aim is to identify and recommend an appropriate wastewater treatment approach that can be used in both domestic and industrial environments to ensure no water goes to waste, is polluted, or poorly managed. The study will also educate communities about the benefits of wastewater treatment and options that can be used to enhance the availability of safe and clean water.

2. Wastewater Treatment Background

2.1. Wastewater Treatment and Sustainability

The term “wastewater as a resource” represents a paradigm shift from what was once considered a liability to an essential resource that can be used in addressing the challenges faced in water supply and sanitation [22,25,26,27]. However, describing wastewater as a resource is just an empty phrase unless technology is added to make the shift a reality [28]. For a long time, wastewater has been considered a liability and a potential source of diseases. People tend to avoid wastewater by creating channels through which the sludge, chemicals, and other sold matter contained in wastewater can be safely disposed of to minimize damage to the human population [29,30,31,32]. However, those who live in arid and semi-arid regions have often been forced to find ways in which wastewater can be converted into economic and domestic use [33].

Wastewater treatment is also a major contributor to the circular economy, in which wastewater has always been considered a valuable resource, rather than a liability [34,35,36]. The circular economy prioritizes the reuse and regeneration of materials and products to minimize pressure on natural resources while supporting environmental sustainability. Wastewater treatment has become an important source of energy, clean water, fertilizers, and nutrients [24,35,37,38]. For instance, it is a crucial source of biogas that can be used for both industrial and domestic purposes. Producing energy from it reduces pressure on natural resources and overreliance on fossil fuels [13,17,39,40,41,42,43,44,45]. Most governments around the world have realized ways in which it can be converted into valuable use, rather than disposed of in nearby rivers, lakes, or oceans [15,46,47]. Additionally, the various benefits of it have drawn significant interest from policy makers who are seeking alternative sources of economic growth.

Organizations such as the World Bank have developed various initiatives aimed at raising awareness about the potential of wastewater as a resource. There is a need for global initiatives that also guide the planning and financing of both wastewater treatment and resource recovery [21,48,49,50,51]. Policy makers also need to develop various measures for promoting the conversion of wastewater into a valuable resource [52]. According to Maurer et al. [53], there is still limited awareness regarding the benefits of wastewater treatment in various parts of the world. Additionally, the decentralized approach to it has proven more effective than the centralized approach [22,54,55]. The decentralized approach gives individuals an opportunity to participate in the treatment [56]. This may include the creation of domestic reservoirs where wastewater is collected and channeled to the treatment facilities. A significant quantity of this comes from domestic activities, including washing and cooking [57,58]. Individuals also need to understand ways in which rain-water runoffs can be channeled to the treatment facilities.

The significant growth in the global population continues to put massive pressure on the natural sources of clean water. About 36 percent of the global population, especially those in middle-income economies, live in areas that experience water scarcity [35]. Rapid urbanization is also creating various water challenges, including inadequate supply of water, degradation in the quality of clean water, and damage to sanitation infrastructure, especially in the proliferation of informal settlements [49]. Only a small percentage of informal settlements are connected to the urban sewerage system [1,59,60]. According to Delanka-Pedige et al. [33], the connection to the sewerage system is the first initiative toward establishing a sustainable water resource management system. However, the sewerage system needs significant funding and has been a major challenge for middle-income economies, where challenges regarding water scarcity are even more prevalent [43,61,62,63]. Financial institutions such as the World Bank have been quite instrumental in funding various projects aimed at recovering value from wastewater.

According to Fito and Van Hulle [12], wastewater management is also a driver toward achieving sustainable development goals (SDGs) in various countries. Specifically, SDG 6 is dedicated to ensuring access to safe drinking water and sanitation for all, with a strong focus on sustainable water resource management, wastewater treatment, and ecosystem preservation. In this sense, for this article, it is relevant that the SDG targets for wastewater treatment include improving water quality, achieving water use efficiency, reducing the number of people exposed to water scarcity, and achieving an integrated water resource management system [44,64,65]. Wastewater treatment can provide clean water for drinking, cooking, washing, and other domestic purposes [33,55,66,67]. Depending on the quality, treated water can also be circled back to the industries to support various needs, including cooling machines [2,22,39]. Treated wastewater can also enhance the supply of clean water, especially in areas facing water scarcity. According to Melo et al. [45], the increased supply reduces the size of the global population that is exposed to the various challenges associated with water scarcity. Wastewater treatment is a significant step towards achieving sustainable development goals and improving people’s health across the globe.

The economic value of wastewater is something that has not been adequately explored. Even some of the most developed economies in the world are yet to realize the full economic value of wastewater. Al-Juaidi et al. [4] indicate that challenges such as poor connection to the sewerage system prevent various economies from realizing the full value of wastewater generated from various sources [68,69,70,71]. One of the biggest advantages of wastewater is that it can be treated to satisfy various demands, including industrial and agricultural needs. Moreover, the by-products of wastewater such as treated sludge can be converted into fertilizers [13,72,73]. Some of the by-products also provide nutrients to improve plant growth and the overall yield, without resorting to potentially harmful chemicals [74]. For instance, wastewater can be processed to a particular quality needed for irrigation and other agricultural purposes. Further treatment of wastewater can also increase the supply of clean water for drinking. Wastewater treatment ensures that nothing goes to waste from a product that would otherwise be total waste.

2.2. From Waste to Resource

From “waste to resource” refers to processes that wastewater undergoes to make it fit and valuable for domestic and commercial use. Primarily, wastewater treatment goes through three main stages to convert it into different products for various needs [35,74,75,76]. As shown in Figure 1 (below), the three steps include primary treatment, secondary treatment, and tertiary treatment. However, preliminary treatment and sludge treatment are added at the beginning and end, respectively [11,25,26,32]. During primary treatment, wastewater is channeled into holding tanks to allow solid particles (sludge) to settle at the bottom while chemicals such as oil float to the top [25]. Primary treatment removes a significant percentage of impurities present in the wastewater. Secondary treatment involves the breakdown of solid waste using aerobic bacteria incorporated into the treatment system [70]. Tertiary treatment involves filtering wastewater to remove nutrients and waste particles that can be harmful to the general ecosystem. The tertiary stage also involves passing wastewater through additional lagoons to remove any remaining impurities or chemicals before the final product is presented for the desired use.

Figure 1. Stages of wastewater treatment, from preliminary to tertiary treatment.

Preliminary treatment is the first step in the wastewater treatment process. The treatment involves the mechanical removal of both coarse and fine solid materials. The wastewater passes through a screening mechanism that traps pieces of wood, rags, plastic particles, and wire, among others [41,55,67,77]. Preliminary treatment removes more than 60 percent of the solid materials from the wastewater. The percentage can also be higher depending on the intended use of the final product. In the case of drinking water, for instance, the preliminary stage may remove more than 80% of the solid materials, leaving very few materials to be removed in the subsequent stages [60,67,68,78,79]. Once the materials are removed, they are either buried or burned. The environmental issues associated with burning have often led to burying as the preferred method for disposing of solid materials [1,3,19]. However, even burying is not environmentally friendly, since it allows chemicals and non-decomposing materials such as plastics to pollute the soil. The quantity of the solid materials extracted from the wastewater usually determines the most appropriate disposal method. Various mechanisms can ensure the safe burning of plastic materials to minimize potential environmental damage [22].

Primary treatment is the second stage of the wastewater treatment process. According to Melo et al. [45], primary treatment allows wastewater or effluent to slowly pass through grit tanks, allowing fine sand particles to settle down. However, it is still possible to have finer sand particles suspended in the wastewater [11,21,34,80]. To remove the finer particles, wastewater is allowed to pass into large primary sedimentation tanks where most of the solid material settles out to form sludge [5]. According to Al-Juaidi et al. [4], primary treatment removes about 60–70 percent of the suspended solid materials. The liquid that remains after primary sedimentation usually contains very fine solids in the form of dissolved matter [12,81,82,83]. This requires secondary treatment to remove any dissolved particles in the water. The primary sedimentation must remove all the solid materials from water that is needed for various purposes such as drinking and cooking. However, for activities such as irrigation, the wastewater may be ready for use if it does not contain potentially harmful chemicals and solid materials [55,83,84].

Secondary treatment is designed to remove between 70 and 90 percent of the suspended solid materials in the wastewater. Secondary treatment is a biological process that usually involves the use of micro-organisms to decompose the organic compounds [7]. Aerobic bacteria are usually used in this process because of their capacity to provide oxidative energy for dissolution of the organic materials [1,2,5,9,22,85]. The amount of available oxygen usually determines how fast the suspended materials are removed using the microorganisms. Two processes can be used during secondary treatment to remove the dissolved materials in the wastewater [34]. The two processes include filter beds and activated sludge. The filter beds are where the wastewater is sprayed slowly over beds of broken stones or gravel to increase the surface area needed for the speedy oxidation process [33]. The wastewater that collects at the base of the filter beds may contain suspended materials that are removed through secondary sedimentation. The activated sludge also contains micro-organisms that are needed for the oxidation and digestion of all the suspended organic matter in the wastewater.

Tertiary treatment is designed to remove toxic compounds, including phosphorus and nitrogen compounds, that cannot be removed during the primary and secondary treatments. Both the primary and secondary treatments can only remove about 20–40% of the toxic compounds or chemicals in wastewater [5,7,20]. Tertiary treatment involves the use of various tools, including UV lights, filter membranes, and other forms of disinfectants [3,5,7,9,12,86]. The main purpose of the tertiary treatment is to ensure the final product does not contain any toxic compound that can be harmful to human beings or plants, especially if the wastewater is used for irrigation [15]. The various tools used in the tertiary treatment are designed to address specific chemical compounds contained in the wastewater. The final product also undergoes thorough screening to ensure it is free from any chemical or potentially harmful compounds [17]. Various cities around the world rely on treated wastewater to boost the supply of clean and safe water for drinking. Keeping the final product free from chemicals is one of the topmost considerations before supplying clean water to consumers.

In the quest for improved sustainability and a more environmentally friendly approach, several innovative processes have been developed to recover resources and energy from wastewater. These methods are vital in contributing to the transition towards a circular economy and enhancing the overall sustainability of various industries. Noteworthy among these processes is the Wastewater to Biogas Energy Recovery process in biorefineries [87].

The Wastewater to Biogas Energy Recovery process is specifically designed to treat wastewater while simultaneously recovering biogas energy from it. It proves particularly relevant for biorefineries that convert plants into fuel, as their wastewater contains abundant organic materials that are challenging to treat using conventional systems. Through this process, biogas, a clean-burning renewable fuel, is extracted from the wastewater, significantly enhancing the economic and environmental sustainability of second-generation biorefineries. This approach not only supports the transition to sustainable, plant-based biofuels and bioproducts, but also helps reduce costs and lower greenhouse gas emissions compared to traditional treatment systems [87].

In the realm of wastewater treatment, conventional methods primarily concentrate on eliminating existing pollutants like heavy metals and organic compounds. However, these methods come with significant drawbacks, such as high costs, time consumption, and energy intensity. A novel approach, known as the advanced sustainability approach for resource recovery, views contaminated wastewaters as valuable resources rather than mere wastes. This paradigm shift involves developing new technologies and materials to efficiently manage wastewater while recovering valuable resources [88].

To achieve enhanced performance and reduce secondary contamination, this approach combines different processes using synergistic effects. Technological innovations play a crucial role in significantly improving pollution removal efficiency. For instance, nanomaterials have shown promising results in enhancing wastewater remediation efficacy. Moreover, researchers are actively exploring more economical and rational strategies for resource recovery from wastewater [88].

Wastewater has evolved from being considered a waste to becoming a valuable resource. It not only addresses water shortages through water reclamation but also provides a medium for energy and nutrient recovery, offsetting the extraction of precious resources. As we move forward, the focus is on identifying viable resource recovery technologies for domestic and municipal wastewater across various scales of implementation. These scales include small-scale, medium-scale, and large-scale systems. Different approaches, such as non-potable reuse (NPR) projects, have been successfully implemented at all scales, which highlights the ease of implementation and lower water quality requirements compared to conventional methods [88].

From a circular economy perspective, energy recovery from wastewater is considered as an exceptional opportunity that brings environmental, political, economic, and social benefits. This approach emphasizes the transition to a circular economy to address challenges related to wastewater reuse and energy recovery, considering societal, regulatory, and political aspects. The circular economy perspective presents various energy recovery technologies for wastewater treatment plant effluents and evaluates their effectiveness. It also highlights practical strategies for implementing energy recovery from wastewater and provides successful case studies covering different potential scenarios [89,90].

Wastewater treatment involves a range of techniques aimed at eliminating contaminants found in wastewater. In Figure 2 are shown some of the common options for treating wastewater [91,92,93,94].

Figure 2. Flowchart to show common wastewater treatments.

It is important to note that the choice of wastewater treatment options may vary depending on the specific characteristics and context of the wastewater being treated. Selection of the most suitable treatment approach is based on technical, economic, social, and environmental criteria, which should be considered in each individual case.

2.3. Contributions to Environmental Sustainability

The primary contribution that wastewater treatment makes to sustainable resource management is the reduction in waste. According to Gernaey et al. [69], waste is a major threat to sustainability because it leads to the depletion of natural resources. Although there is sufficient water to meet the needs of everyone around the world, a lot of it goes to waste [95]. Additionally, most of the water is inaccessible to a significant percentage of the global population. Nearly 36 percent of the global population lives in areas where they face significant water scarcity [6,10,17]. Therefore, letting a significant amount of wastewater go to waste can be harmful to people who face water scarcity. Even those who live in areas with an adequate supply of water may face scarcity if continuous waste amounts to the depletion of natural resources [41,45,57,61,96]. Wastewater treatment turns potential waste into a valuable product that can be used for both domestic and industrial use. Moreover, wastewater treatment protects natural sources of water from potential depletion.

According to Kamali et al. [17], the role of sustainability is to ensure that natural resources are always available to meet the needs of both current and future generations. One of the biggest threats that the world is facing is the potential depletion of natural resources due to growing populations and demands [71,78,82,97]. For instance, most forests that were once covered with green vegetation have been turned into farmlands, industrial parks, and cities where people live. Once green places have been turned into concrete to meet the needs of people [40]. Trees and forests are major components of the water cycle. Water that evaporates from the seas and trees is eventually converted into clouds and rain through a process known as condensation [30]. Deforestation presents a significant threat to water sustainability by cutting off a significant supply of vapors needed for rain formation [23,45,50,98]. Wastewater treatment addresses this challenge by ensuring there is a significant amount of water for both industrial and human consumption. Additionally, it is important because it considers SDG 6, which aims to ensure the availability and sustainable management of water and sanitation for all [44,64,65].

Wastewater treatment is also a source of green energy in the form of biogas. According to Melo et al. [46], climate change can be avoided or minimized if the global population turns to green sources of energy and cuts down their reliance on fossil fuels. Wastewater treatment has demonstrated a significant capacity to produce clean energy that can be used in powering the entire treatment facility or for domestic purposes [76,79,82]. During secondary treatment, the use of microorganisms or bacteria to absorb the suspended solid materials usually produces large quantities of biomass. At temperatures of about 35 degrees Celsius, biodigesters used in the decomposition of organic matter can produce large quantities of biogas [13,99,100]. A combustible gas known as methane forms the largest part of biogas. According to Al-Juaidi et al. [4], methane can be used to generate the required energy for powering the entire wastewater treatment facility. The methane obtained from the biodigesters can also be processed, packaged into gas cylinders, and sold to potential consumers to be used at home or in industrial processes [11,17,19,101]. This will reduce the dependence on fossil fuels and protect the environment from its consequences.

Scientific studies indicate a continuous decline in the sources of clean water around the world. Factors such as climate change, drought effects, increased urbanization, farming, and the growing population are putting excessive pressure on the few sources of clean water that are still available on the planet [33,39,41]. Scientists believe that much of the current water sources will be lost over the next 10 years if nothing is done to prevent the current onslaught [60,63,78,99]. The projected population increase over the next 10 years has also generated significant concerns about the demand and supply of clean and safe water. Wastewater treatment has become an important source of clean water [35,37,45,71]. Wastewater treatment is ensuring there is a balance between supply and demand. Since the current demand exceeds the supply, there is a need for additional sources of water to minimize scarcity in the cities, especially informal settlements, which are more vulnerable to water scarcity [11,18,49,102,103]. Wastewater treatment also protects the water cycle by maintaining biodiversity.

Although fossil fuels account for most of the current fertilizer supply, wastewater treatment is promising a more effective organic fertilizer that is less harmful to the environment [80,104,105,106]. The fertilizer obtained from fossil fuels has various associated concerns, including algae blooms and soil acidity [50]. The use of chemical fertilizers has also been associated with various concerns, including health concerns. Replacing chemical fertilizers with organic fertilizers will protect the environment and consumers from the potential dangers associated with the chemicals [42,107,108]. The organic fertilizers are obtained from the organic matter that is present in wastewater. One of the major benefits associated with organic fertilizers is the rich nutrients that not only support growth but also provide nutritional benefits to consumers [61,75,79,109]. The use of organic fertilizers also enhances soil sustainability by minimizing the chances of acidification.

3. Methods

In this study, a systematic review of the literature was chosen to determine if the practice being studied is based on sufficient evidence. The PRISMA checklist document is provided in the Supplementary Materials (See Table S1). According to Muga and Mihelcic [25], a systematic review of the literature is always the best option when researchers want to determine if a given practice is supported by sufficient evidence. In this case, the methodology helped to determine if wastewater treatment supports sustainable water resource management as indicated in the hypothesis [34]. Evidence obtained from a systematic review of the literature helps in providing concrete answers to specific research questions [29,57,99]. For instance, a practice is only valid or scientifically relevant if there is sufficient evidence to support it. Any practice that is not supported by evidence can be harmful or a potential waste of resources. Most systematic reviews are based on primary studies that were conducted using various research designs, including experiments, randomized controlled trials, and quasi-experiments [27]. The systematic reviews help in identifying gaps in the evidence and proposing future studies.

Apart from answering specific questions, a systematic review of the literature was also selected for this study because it is detailed and comprehensive. The first step in-volves the formulation of the research question to guide the research. In most cases, the CIMO (Context, Intervention, Mechanisms, and Outcomes) approach helps in formulating specific questions, focusing on the problem, intervention, comparison, and outcomes [110]. In the case of wastewater treatment, a comparison can be drawn to letting wastewater go rather than subjecting it to treatment. The research question may differ based on the type of study and the required outcomes. Most systematic reviews are used in medical research where they assist in answering specific clinical questions [111]. From the research question, the researchers can identify the keywords and use them to search for the previous studies. Strict eligibility criteria must be developed to ensure that only relevant articles are selected to answer the research question [110,111]. The criteria help in eliminating articles that are not related to the research question or are too old to be included in the study. For instance, the studies conducted in the 1970s or 90s were not used in the study because they are too old and do not reflect the latest findings on a topic.

Systematic reviews are also effective in producing accurate and reliable results. The results obtained from a systematic review can be analyzed using a narrative approach or quantitative approaches such as correlation measurements, meta-analysis, and other numeric estimates [110]. In both correlations and meta-analysis, there is a confidence level that helps in determining the overall accuracy and reliability of the results. For instance, in correlations, a confidence interval determines the degree of certainty to which the given results fall within the range of the confidence level. A 95% confidence interval indicates that the results have a high degree of certainty, indicating a strong or negative correlation between two variables [110]. In this study, a narrative approach was used to analyze the results obtained from the previous studies. Both the narrative and quantitative approaches are acceptable routes for analyzing and drawing logical conclusions from the available data.

A systematic review of the literature was also deemed fit for this study because they are exhaustive, comprehensive, and reproducible. Systematic reviews are exhaustive be-cause every detail of the evidence is used in synthesizing the outcomes. The use of primary sources also improves the quality of evidence, especially if the researchers used experiments, observation, randomized controlled trials, or case studies [111]. For instance, some scientists examined the application of wastewater treatment in countries such as China and how it leads to sustainability. The outcomes of systematic reviews are also reproducible to enhance the overall degree of accuracy. Most of the methods used in systematic reviews have been tested in various studies to determine their accuracy and ease of reproduction [110]. It is also easier for the academics to trace their steps and identify areas where there were omissions. Moreover, the study aimed at making sufficient evidence available to support the use of wastewater treatment to achieve sustainable resource management [111]. Gaps identified in this study will also assist in developing and conducting future studies to provide answers to questions that were not adequately addressed in the previous studies.

3.1. Question Formulation

Research question formulation is a delicate process that plays a key role in deter-mining the overall outcomes. The formulated question produces key words, qualitative variables, and directions that researchers should take to provide accurate answers. Various methods or logic can be used to develop specific and accurate questions. One of the most reliable logics is CIMO. The CIMO logic is more applicable in non-medical research where there is a limited requirement to compare interventions [107]. Moreover, the CIMO approach is more simplified and easier to apply even in studies involving big data analysis.

In this study, the research question was formulated using the CIMO approach. The context (wastewater treatment), intervention (implementation or integration), mechanisms (sustainable resource management), and outcomes (efficiency). The final question read as follows: “Does wastewater treatment lead to sustainable water resource management?” The question examines the role of wastewater treatment in contributing to sustainable resource management. The question also examines the various benefits that society is likely to gain from wastewater treatment. The question also touches on responsible consumption and production to ensure there is a sufficient quantity of clean water for drinking to meet the needs of the global population.

3.2. Source Identification

The two methods used in the second step, after formulating questions, included searching using “the Web” and “Boolean Operators”. The web search involved the use of keywords to identify and retrieve articles that are related to the research question and qualitative variables. The keywords included wastewater treatment, sustainability, and water management. They were used in combination to enhance the accuracy of the outcomes. For instance, “wastewater treatment” and “sustainable management” were used in combination to obtain articles that examined the relationship between wastewater treatment and its role in sustainable water management. The purpose of using the keywords was to enhance the accuracy of the articles.

The Boolean operators approach was also used to combine search terms in ways that broaden and limit the search results. For instance, if the keywords “wastewater treatment” are used in the search for articles, it broadens the search by returning nearly all the articles regarding wastewater treatment. However, the use of combined keywords such as “wastewater treatment and sustainability” limits the search results by returning mostly articles focusing on sustainability. Boolean operators are more effective when the re-searchers need to broaden the search while limiting the results to specific terms or years of publication. Boolean operators can also be used to limit the databases or journals where the results should come from. In the case of wastewater treatment and sustainability, the databases included Resources, Conservation and Recycling, Sustainability, Nature, Waste Management, and Journal of Industrial Ecology. The Boolean operators played a significant role in limiting the search results to the specific inclusion and exclusion criteria.

The Boolean Operators were also useful in receiving more articles using a method known as snowballing sampling. Snowballing sampling is used when the identified results do not provide direct answers to the research questions [108]. In snowballing sampling, the researcher relies on the reference list of the identified articles to obtain more specific articles that can provide more direct answers to the research question [108]. However, snowball sampling presents additional tasks and may be difficult in a case where the researcher has to deal with several articles. The snowball sampling includes additional evaluation of the articles and may not meet certain inclusion criteria such as year of publication. This helped in expanding the number of articles used in the research and adding strength to the evidence.

Six factors were considered when identifying and selecting the most appropriate articles for further analysis, as shown in Figure 3.

Figure 3. Flowchart to identify and select literature.

In the first factor, the researcher asked if the article contained new and significant information, including adequate justification for the findings. Originality was an important factor to consider, because the primary role of research is to present new information and contribute to the growth of information literacy. Articles that presented new information on the topic were more likely to be selected by the researcher than articles that were simply regurgitating what other researchers found in their primary studies. The researcher also gave significant priority to the original data that were obtained using primary research methods. Original articles also boost the overall strength of the evidence since they provide new information that is missing in other publications.

In the second factor, originality and relevance to the research question were very crucial. The papers had to demonstrate an adequate understanding of the literature and support their arguments with a wide variety of articles and concepts. It was also important to examine if any significant work was ignored. This would assist in identifying research gaps and areas that future researchers should focus on. A thorough evaluation of each article was required to ensure all the relevant information was included by the researchers. At some points, screening the articles using the abstract was not enough to establish the position of the researchers. It also took a significant duration to screen all the selected articles and put the obtained information into the right context.

In the third factor, according to Fito and Van Hulle [12], the methods used in research determined the overall quality of the outcomes, including limiting potential biases in the results. For this reason, the reliability and validity of the results are fully dependent on the methods used in both data collection and analysis. The validity ensures that the results obtained are accurate and verifiable, while the reliability ensures that the same results would be obtained if a similar methodology is used in collecting data. Crucial factors to consider included the research design, sampling procedures, data collection instruments, and methods used in analyzing the outcomes. It was also crucial for the researcher to determine if the equivalent work on which the paper is based is well-designed and backed with sufficient evidence.

In the fourth factor, the findings provided details about the outcomes of the research and whether they adequately address the research questions and hypotheses. Analysis of the results began with a closer examination of the abstract. The review focused on the results that were found in relation to the research questions, methods used in collecting data, and analysis of the results. The researcher also examined if the results were properly interpreted to explain their implications on the issue under investigation. Papers that qualified for review fully satisfied both the analysis and conclusion criteria. They were also based on the recent findings, within the last five years, to reflect current trends in the market.

In the fifth factor, the first question was to determine whether the results met the intended objectives of the study. This was crucial, since the results that fall below the objectives allow gaps that should be explained by the researcher. Papers that qualified for review met all the objectives that the researchers sought to achieve. The second issue was whether the results aligned with the modern practice requirements. In the case of wastewater treatment, the researcher was looking for those who connected their findings to sustainability. The researcher also examined how the findings connect to the needs of society. In this case, the paper examined how the findings provide solutions to water scarcity around the world. It was also crucial to examine how the researchers connected their findings to the current and future challenges regarding clean water and sanitation.

In the sixth factor, elements to consider included whether the papers clearly expressed their case, measured against the language of the expected knowledge or the journal standards. Papers that qualified for review clearly expressed themselves and met the language expectations, including the use of terminologies associated with the research problem. The selected papers also avoided the use of jargon that may confuse readers and limit their capacity to internalize the contents of the paper. They also avoided the use of acronyms without explaining what the individual letters represented. Those which were selected met all the standards of the peer-reviewed journals and were selected based on their relevance to the research questions and hypotheses.

3.3. Selecting and Evaluating Sources

The article selection occurred in two main phases, beginning with the abstract screening. An organized abstract contains three main sections, including background, methods, and results or findings. Screening through the abstract provides information about the purpose of the study, background information, methods used in collecting and analyzing data, and the findings. The second phase examined if the articles met the inclusion criteria. The basic inclusion criteria included the year of publication (2000–2023), wastewater treatment, sustainable water management, journal, book, and authoritative website. The inclusion criteria also included an examination of whether the articles were biased regarding funding or affiliation. Funding bias affects the quality of the outcomes because it prevents the researcher from disclosing information that can be potentially damaging to the organization or individual funding the research. The articles that were used in this study met all the inclusion criteria and were deemed appropriate and relevant to the research topic.

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) model was used in the study to synthesize and select the most appropriate results [110]. The total number of articles obtained from manual research was 350. However, not all these articles were eligible for the study. Most of them did not meet the year of publication requirements which limited the articles to a period between 2000 and 2023. More than 250 articles were rejected for being duplicates, ineligible, or removed for other reasons such as the year of publication. The remaining 100 articles were further subjected to further evaluation to identify the ones with specific answers to the research question. A total of 46 articles met the final criteria and were selected based on their relevancy and accuracy in answering the research question. The remaining 68 articles are included in the references list to add more perspective to the arguments made in this paper.

3.4. Data Analysis

The retrieved articles (n = 46) were classified into various critical dimensions for analysis, as shown in Figure 4. The main classifications included title, document type, authors, and main findings. The analysis involved examining each of the findings to determine how they relate to sustainable resource management. The study aimed at determining if wastewater treatment correlates with or supports sustainable resource management. Each of the findings was carefully examined to determine the correlation between wastewater treatment and sustainability. The comparisons also included similarities and differences among the findings.

Figure 4. PRISMA flowchart.

4. Results

The application of PRISMA helped in narrowing the results to identify the most accurate articles that provided answers to the research question. The research also evaluated evidence to enhance validity and reliability. The results were also ranked based on strength, content validity, bias, and application to wastewater treatment and sustainable resource management. A summary of the findings is shown in Table 1.

Table 1. Selected Articles.

5. Discussion

This research asks, “Does wastewater treatment lead to sustainable water resource management?” Considering the hypothesis of this research, the findings indicate that wastewater treatment contributes toward economic and environmental sustainability in four ways: converting waste to clean water (Section 5.1), converting waste to energy (Section 5.3), reducing the environmental effects of wastewater (Section 5.4), and builds sustainable cities and communities (Section 5.5). The evidence provided in the table also indicates the relationship between “sustainable outcomes of wastewater treatment” (qualitative variable) and “wastewater treatment techniques” (qualitative variable). A detailed discussion of the findings is provided below.

5.1. Converting Waste to Clean Water and Sanitation

The rigorous process of wastewater treatment ensures that the final product is clean and safe water that can be used at home for various purposes, including drinking, cooking, and sanitation [30]. In the circular economy, the wastewater that is generated from home can also be channeled back to treatment facilities for various purposes such as irrigation [33,49,51]. In places such as urban areas where there is prevalent water scarcity, wastewater treatment provides an alternative source of clean and safe water for domestic use [22,33,57,69]. Most of the informal settlements where water scarcity is a major problem can rely on wastewater treatment to boost the supply of clean and safe water. According to Nair Manu and Azhoni [26], wastewater treatment is likely to improve the supply of clean water around the world and offset the demand that has become very difficult to fulfill.

The provision of clean water for domestic and commercial use contributes towards sustainability by protecting natural water sources from potential depletion. Gernaey et al. [69] describe sustainability as the use of resources in ways that ensures that they are al-ways available for the coming generations. Although water is one of the most abundant commodities on the planet, accessibility remains a significant challenge [27,95,98]. The chances of depleting the natural resources in places that experience arid and semi-arid climates are quite high [78,81,99,102]. Approximately 771 million people, which is around 1 in 10 individuals worldwide, still lack access to clean water. This lack of access to safe drinking water has severe consequences, leading to 1.2 million deaths annually caused by unsafe water sources, with 6% of deaths in low-income countries attributed to these sources [112].

Jamrah et al. [15] estimate that most places that experience water scarcity are likely to face even bigger challenges over the next ten years as the problem intensifies. Unless something is done to reverse the current challenges, a huge section of the global population is likely to face significant water shortages and potential consequences, including diseases [33]. Instead of letting large amounts of water go to waste, the treatment process turns potential waste into valuable products that can protect the world from potential dangers associated with water shortage.

Apart from reducing pressure on the natural sources of water, wastewater treatment reduces waste, which is necessary for sustainability. Sustainable strategies depend on the capacity to reduce waste while controlling consumption and production [60,75,79,82]. Most organizations rely on the Six Sigma approach to enhance economic sustainability by reducing waste while expanding productivity [35,47,51]. In the case of sustainable re-source management, wastewater treatment plays a significant role in reducing waste and boosting the supply of water as a crucial commodity. Singh et al. [30] describe waste as one of the biggest challenges limiting the earth’s capacity to maintain its resources. The growing human population and increased demand for essential resources indicate that various sources of water could be depleted even before the end of the current century [99,103,107]. By reducing waste, the treatment process ensures that the natural resources remain active to serve the current and future generations.

Wastewater treatment also promotes good behavior in society. According to Navarro-Ramírez et al. [27], studies have shown the centralized approach to sustainability is not working because most of the government efforts end up being opposed or are too little to address a major problem [22,36,44,48]. Indeed, governments cannot keep up with the pace at which people consume water and other essential commodities. Attempts to initiate measures such as increasing taxation to reduce overconsumption have not generated the desired outcomes. The decentralized approach ensures that people can take the initiatives to minimize waste [51,54,64]. However, this cannot only be effective if people are informed about the benefits of wastewater treatment and how they can minimize waste at home. Raising awareness about water conservation may assist many governments to enhance water conservation and minimize waste [77,97,101]. Additionally, raising awareness is likely to convince more people to join the national or urban sewerage system to have their homes connected to water treatment facilities.

5.2. Role of Technology in Wastewater Treatment and Sustainability

Wastewater treatment can be challenging without using various technologies to achieve the desired goals. Wastewater treatment occurs through a series of steps, including coagulation, flocculation, sedimentation, filtration, and disinfection [21,45]. Technology is usually involved in every step of the wastewater treatment process. Some of the latest technologies include an activated sludge model, bio-oxidation process, advanced oxidation system, aerated lagoons, aerobic granular reactors, and aerobic granulation [78,83,102]. The main purpose of technology is to perform significant tasks or facilitate systems throughout the treatment process. For instance, the aerated lagoons provide a platform for oxidizing the wastewater so that micro-organisms such as bacteria can decompose the suspended organic compounds and make the water safe for the intended use [27]. The aerobic granular reactors also create suitable conditions to favor the decomposition of the organic matter suspended in the wastewater [41,57,83,99]. The technology ensures that wastewater treatment occurs more efficiently and cost-effectively.

Technology is also suitable in the analysis of processes to identify areas of weak-nesses and minimize potential disasters. The wastewater treatment system is designed in a way that makes it vulnerable to potential disasters such as fire or spillage into nearby farms or homes [44,49,51]. The oxidation process and decomposition of the suspended organic matter produce various gases, including methane [60,71]. One of the dangers of methane is that it is highly combustible and can cause massive explosions if exposed to fire [77]. Technology helps in analyzing the entire wastewater treatment system to identify specific areas of weaknesses and recommend suitable solutions [98]. Data analysis is part of the risk assessment which occurs daily or weekly, depending on the management’s policy. The technology prevents damage and ensures that wastewater treatment goes in accordance with the plan. Investments in the latest technology such as artificial intelligence are also crucial in automating the processes, reducing waste, and enhancing the overall operational efficiency [78,99,102]. Artificial intelligence is more effective in reading the machines and providing real-time monitoring and maintenance.

Wastewater treatment enables people to discover various technologies that can be used in achieving sustainable development goals. Technology enhances sustainability by giving policymakers the tools they need to make informed and timely decisions [44,49,55,61]. For instance, data analysis enables policy makers to identify potential risks that can damage the sewerage treatment system. The automated processes also enhance operational efficiency and reduce potential waste of resources [67]. The use of technology helps in saving resources and minimizing pressure on the environment [71]. For instance, wastewater treatment is usually powered by the biogas that is produced during the de-composition of the organic matter. Technology is needed to help in the production of clean energy and reduce dependence on the fossil fuels such as diesel used in running power generators [98,103,109]. Technology also generates value by reducing expenditures on fuel, lowering the overall cost of running wastewater treatment facilities.

Sustainable resource management is not just about policies, but also the use of technology to support decision making. According to Gernaey et al. [69], sustainable resource management involves monitoring natural resources and taking immediate measures to eliminate potential threats. Technology helps in collecting essential data that enables policy makers to monitor the threats facing forests and other water catchment areas [95,98,106]. For instance, technology can be used in collecting data regarding land and water-use in a given area. In a country such as China, technology has been used for many years in collecting data regarding the amount of water needed by the farmers to support rice and other types of farming [55,57,69]. The accurate data enables policy makers to allocate sufficient resources to specific activities aimed at addressing the key challenges facing natural resources [67]. Data can also help in predicting future trends and developing sufficient steps to protect natural resources from potential harm. Technology has made sustainable resource management more effective by providing information and guiding practices that are beneficial to the environment.

5.3. Converting Waste to Energy

Waste to energy (WTE) is a term that refers to processes that convert waste into a clean source of energy for cooking, heating, lighting, and powering vehicles. For a long time, sources of energy have been a significant source of concern among policy makers [55]. The use of fossil fuels continues to raise concerns over their overall cost to the environment. The need for a clean source of energy with minimal impact on the environment has been a major priority among policy makers [32,79]. Wastewater treatment provides an alternative source of clean energy that can be used for powering homes and commercial facilities. The biogas obtained from the decomposition of organic matter during wastewater treatment is also capable of powering vehicles and replacing gasoline, diesel, and petrol [39,79,108]. However, the cost of developing sufficient biogas to replace fossil fuels remains a significant challenge. Additionally, most wastewater treatment facilities have not established sufficient capacity to treat or convert waste into energy [11,19,97,104]. For instance, only 40–50 percent of the current wastewater treatment facilities can convert waste into energy for both domestic and commercial use. The average energy produced from converting wastewater to energy can vary depending on multiple factors. These factors include the specific technology and process used for conversion, the composition of the wastewater, and the scale of the conversion facility.

Since energy is one of the greatest sources of air pollution, wastewater treatment has demonstrated a significant capacity to provide a sustainable solution to the problem [46]. Most wastewater treatment plants have on-site anaerobic digesters that can produce biomethane, an important source of clean energy. By estimates, about 1260 wastewater treatment plants can produce a total of 5 million gallons of biomethane [11,77,97]. If the biomethane is channeled into the gas grid, it can power homes and industries, reducing carbon emissions by about 2.3 million metric tons daily [56,68,78]. This is equal to the annual emissions of about 430,000 fossil-fueled passenger vehicles. Wastewater treatment is capable of reducing the overall dependency on fossil fuels as the primary source of energy [98,105]. However, this would require significant investment from various governments around the world to achieve the desired milestone. The current cost of converting waste to energy remains a challenge that would require a collective effort from many governments around the world.

Converting waste to energy is also likely to reduce the current cost of fossil fuels around the world. The high prices of oil and gas continue to affect many families around the globe. According to Nair Manu and Azhoni [26], oil prices have increased by significant margins since the pandemic, making essential commodities difficult to acquire for many families. Moreover, the main challenge with fossil fuels is that not enough alternatives have been produced to rival the mainstream supply of oil and gas [9,11,98]. Wastewater treatment may solve the problem by providing an alternative source of energy that people can use at home and in their industries [75,83]. This will reduce demand for fossil fuels and lower prices to levels that people can afford. Since the production of biomethane is likely to be less costly once the facilities are constructed, it will enable many people to afford clean energy [86,103,107]. Lowering the prices of oil and gas will also reduce the cost of production in the industries, and eventually contribute towards lowering the current level of inflation that continues to affect many economies around the world.

Wastewater treatment also creates opportunities for innovations around energy production. As the world grows wearier about the effects of climate change, scientists have been working towards developing more innovative approaches to energy production [105]. The production of electricity, for instance, remains a significant challenge to those who are concerned about the effects of climate change and environmental degradation [56,66]. While electricity is a clean source of energy, its production has never been clean or sustainable. Most of the electricity used around the world is produced using fossil fuels such as coal and diesel. Current innovations have focused on converting solar and wind into sustainable sources of electricity [34]. However, wastewater treatment provides opportunities for scientists to explore other sources of clean energy to support solar and wind. Innovations around biomethane would assist in making the gas more stable and efficient for large-scale applications [11,18,29]. The current innovations will also motivate future researchers to create better sources of clean energy from wastewater.

Sustainable resource management demands that nothing that contains potential value should go to waste. However, it may be difficult to understand the value of wastewater until the treatment and by-products are made available [105]. Rather than al-lowing wastewater to go into total waste, it is more economically and environmentally viable to extract the potential value that it contains [79]. Waste management is an important part of sustainability because it limits pressure on natural resources and prevents potential depletion. The current natural resources have been subjected to significant pressure and require innovative solutions such as alternative sources of energy [61,78,101]. The reduction in waste also saves the environment from the environmental damage associated with wastewater. Examples include nutrient pollution, oxygen depletion, toxicity impacts, and floating debris [44,97,99]. Wastewater pollution is something that has not been adequately addressed in previous studies. Turning wastewater into useful products such as energy is an innovative approach to sustainable resource management.

5.4. Reducing the Environmental Effects of Wastewater

Although the environmental consequences of wastewater have not been adequately addressed in previous research, there is a need to raise awareness about the problem so that more people can understand why wastewater treatment is necessary [98]. One of the biggest challenges associated with wastewater pollution is known as nutrient pollution. According to Singh et al. [30], nutrient pollution occurs when excessive nutrients in the wastewater are washed down into the rivers, lakes, or oceans where they cause massive destruction. The massive effluents that are washed down into the oceans mostly contain phosphorus and nitrogen [76,79,81]. Once these nutrients touch the bottom of the lake or river, they cause a phenomenon known as algae bloom. Algae take up all the oxygen that supports aquatic life, including fish and plankton. The depletion of oxygen is also harmful even to animals such as alligators and turtles that spend most of their lives in water [3,7,9]. Wastewater treatment ensures that these nutrients are converted into organic fertilizers, rather than allowing them to cause nutrient pollution.

The presence of many toxic substances in wastewater effluents is another significant concern associated with wastewater. The toxic substances are often fine particles that may be difficult to see unless the wastewater is subjected to chemical analysis [19,21,67]. During the second phase of wastewater treatment, the effluent undergoes screening to determine the toxic substances or chemicals dissolved in the water [9]. The removal of toxic substances such as ammonia may require more advanced technologies to prevent returning such substances into circulation [7,12,18,69]. Treatment not only saves waterbodies from toxicity but also protects the soil from potential danger. There are also uncertainties regarding the actual impact of toxic substances on living organisms [68]. Very little is known about the actual consequences of toxic chemicals on human life. Wastewater treatment limits the chances of being exposed to toxic substances that can be harmful to both humans and aquatic life.

Another environmental concern associated with wastewater is floating debris. Most of the floating debris consists of plastic waste and other materials that have been swept down into rivers or lakes [39]. The floating debris affects aquatic life by preventing sunlight that enables plankton to grow. The limited sunshine penetration may also create significant changes in the water temperatures, sometimes forcing aquatic life to re-adjust to the new conditions [44,56,65,71]. The floating debris also affects the movements of fish and generates massive death, making the water even more toxic. If not removed, the floating debris can also affect the recreational use of the rivers and lakes [100]. The surrounding waterbodies are essential both for drinking and recreational purposes. Activities such as swimming and boat riding provide opportunities for the community to come together and explore their talents [108]. However, the floating debris affects the general water surface and prevents both the recreational use and the overall social value of the nearby rivers and lakes.

Wastewater treatment also protects people from drinking contaminated water. Drinking contaminated water can expose humans to various bacteria, viruses, and other dangerous micro-organisms such as giardia and cryptosporidium [98]. Most of these bacteria or viruses are in microscopic forms, making them difficult to see without the help of devices such as microscopes [44,69,97]. While water may appear clean on the surface after the sedimentation, it may contain harmful micro-organisms that are associated with various gastrointestinal diseases, including typhoid, dysentery, and cholera [21]. Wastewater treatment prevents the discharge of potentially harmful effluent into nearby waterbodies. Some of the irresponsible practices that have been noted in the past include discharging industrial effluents into the nearby creeks and rivers [79]. Even some of the most renowned companies such as Monsanto have a disturbing history of discharging industrial effluents into the nearby creeks and rivers [45,78,98]. Wastewater treatment protects human beings from potential catastrophes associated with domestic or industrial effluents.

5.5. Sustainable Cities and Communities

Wastewater treatment creates sustainable cities by ensuring there is sufficient water supply to meet the ever-increasing urban needs. Wastewater treatment is designed to maximize the supply of water, especially to deprived areas such as informal settlements [84,98,106]. Currently, more than half of all accessible water runoff is used by human activities. Industrial purposes account for approximately 90% of total water use, while domestic purposes constitute less than 10%. Although households are the smallest consumers of water, they possess significant potential to impact water conservation. By implementing water-saving habits and strategies within their homes, households can contribute to reducing water consumption and promoting conservation efforts beyond their own premises. Household water usage is projected to be the fastest-growing sector, expected to increase by over 80% in the next 25 years. This sector serves as a testing ground for developing strategies and promoting social behavior changes aimed at reducing water consumption in agriculture and industry [113]. Many cities around the world have created wastewater treatment plants to boost their water supply while maintaining high standards of hygiene in the cities [23,49,51]. Even in sub-Saharan Africa where water scarcity is prevalent, wastewater treatment is providing sustainable water supply to both urban and suburban populations. According to Navarro-Ramírez et al. [27], the growing urban population has pushed many families into informal settlements where the supply of water remains problematic. The growing urban population also means that more water is needed for both domestic and industrial use. Wastewater treatment provides a stable supply of water without exposing natural sources to potential depletion [98,109]. For a sustainable city, clean and safe water is needed for maintaining high standards of hygiene and protecting people from potential diseases.

According to Nair et al. [38], low-cost and decentralized wastewater treatment plants are addressing the prolonged imbalances between demand and supply of water in various communities. The decentralized wastewater treatment plants are aimed at providing sustainable solutions, especially in communities where there is a significant risk of water scarcity [67]. The decentralized system is also cost-effective because it does not have to connect hundreds of homes to a single wastewater treatment plant. Instead, a community can develop several small wastewater treatment plants to enhance access to sustainable solutions [69,78]. Moreover, the decentralized system educates communities about the value of wastewater treatment and how they can treat it even in their homes [29,39,48,59]. The increased awareness enables people to set up wastewater treatment facilities even in their homes. Other benefits such as the generation of energy help various communities around the world to boost their energy supply and minimize dependence on the national grid system [79,95,99]. Wastewater treatment plants ensure that communities have sufficient access to clean water and sanitation.

5.6. Challenges in Wastewater Treatment

One of the biggest challenges in wastewater treatment is the huge cost of setting up the treatment facilities. According to Manning et al. [81], the average cost of setting up a functional wastewater treatment plant ranges between GBP700,000 and GBP2.5 million, depending on the facilities required by a city [81,102,105]. The huge cost of wastewater treatment makes it unavailable to low-income communities despite its advantages in enhancing sustainability [31,39,41]. The high cost of installation also prevents many cities in low-income regions to build good facilities for both wastewater treatment and energy generation. The high cost of implementation is also discouraging many potential communities from creating small wastewater treatment facilities [50,60,75]. Most governments in low-income economies rely on donations and grants to implement such projects, since the cost may be too heavy for the taxpayers [40,50,71,97,104]. Despite the cost being too high for some administrations, wastewater treatment is a necessity that cannot be ignored. Cities and communities have to source funds and use them to create treatment plants to improve both water supply and general hygiene.

Another significant operational challenge facing treatment facilities is the huge cost of energy. Wastewater treatment plants consume about 2–3% of the electrical energy in most developed economies [100]. Wastewater treatment plants are among the largest consumers of electrical energy in the world. While the solution to this challenge is the production of biomethane to complement electrical sources of energy, most wastewater treatment plants have inadequate capacity to produce sufficient electrical energy [109]. Currently, the electrical energy generated by wastewater treatment plants can power between 50% and 60% of the facilities [49,109]. This leaves about 40% of the facility that has to be powered by alternative sources. The huge cost of electricity is a recurrent cost and has to be met by the administrators regularly. However, this challenge can also be solved by turning the sludge obtained from the wastewater into valuable products such as fertilizer for commercial use [106]. The income generated from the various activities within the treatment plants can assist in meeting some of the recurrent costs and ensuring that the plants remain operational.

Most of the wastewater treatment plants around the world face staff shortages. Staffing is a major challenge that can paralyze the operations of the plant. Individuals who work at wastewater treatment facilities are highly trained and certified by the relevant agencies to provide the required services [98]. However, the cost of hiring the most qualified staff to provide the desired services remains a significant challenge. Some of the facilities address this challenge by training their internal staff to provide the services they need [19,24,95]. This can be achieved by recruiting those who have little information about wastewater treatment and training them until they become fully fledged experts who can provide the required services [49,54,56]. Training also creates a loyalty program that encourages the employees to stay longer in the facility. Staying longer is also beneficial to the facility because the highly experienced staff can pass their knowledge to the recruits through mentorship programs [78,97,99]. Creating a loyal staff enables the company to minimize the cost of operations and enhance overall efficiency.

Another significant environmental challenge facing wastewater treatment plants is the disposal of excess sludge. Both the primary and secondary treatment processes create large quantities of sludge that must be removed to create room for the treatment of more wastewater [81,95,100]. While the sludge contains significant nutrients, it may also contain chemical compounds that can be harmful to the soil. The disposal of excess sludge is a challenge that must be considered when establishing a wastewater treatment facility [96]. The solid material that remains after wastewater treatment can be a great source of fertilizer since it contains sufficient nutrients. In some treatment plants, some of these solid materials are processed to determine if they contain harmful chemicals and channeled to the farms to increase crop yield [35]. However, in a case where the quantity of the sludge overwhelms the amount that can be processed for fertilizer, it becomes a major challenge to the organization [53,67,70]. One of the solutions to this challenge is burying the excess sludge. However, the treatment facility may require a large piece of land to safely dispose of excess sludge.

The activated sludge may also face many challenges, including the fact that the size of land needed for sludge production may not be available for many municipal administrations. The primary and secondary treatment processes require a significant amount of land to install various tanks to act as aeration basins [23,67]. However, the large area of the land is not always available, innovative solutions must be developed to ensure even small pieces of land can provide sufficient ground for sludge production [23]. One of the innovative solutions is the use of advanced technology known as a membrane aerated biofilm reactor (MABR) to increase biomass concentration. According to Manning et al. [81], a higher concentration of biomass per unit volume is a crucial solution to the problem. The maximization of biomass per unit volume is one of the leading strategies for reducing the footprint so that municipals can still achieve the desired goals using the available piece of land [45,97]. Moreover, sustainable resource management relies on innovative solutions to reduce pressure on natural resources.

Other challenges that municipalities may face include meeting the required standards set by the various agencies, including the National Green Tribunal (NGT), fragmentation of information, and the need for real-time monitoring [38]. The wastewater treatment standards are the limits of the chemical that must be met for the treated water to be declared as safe for the intended use [49,64]. The fragmentation of information occurs when the information does not reach the intended target. For instance, if the information meant for a given station manager does not reach the required recipient, it may lead to a breakdown in communication which is potentially harmful to the communication system [27]. The wastewater treatment facility also requires real-time monitoring to prevent potential accidents while delivering the desired outcomes [31,47,49,51,52,53]. Without sufficient staffing, it may be difficult for the wastewater treatment facility to provide real-time monitoring. The use of technology to automate processes is one of the leading strategies used by wastewater treatment plants to provide full-time monitoring and timely interventions.

6. Conclusions

The main objective of this study was to examine whether the available evidence supports the use of wastewater treatment for both environmental and economic sustainability. The results indicate that wastewater treatment contributes toward economic and environmental sustainability in four ways: converting waste to clean water, converting waste to energy, reducing the environmental effects of wastewater, and building sustainable cities and communities. The evidence also indicates the relationship between “sustainable outcomes of wastewater treatment” (qualitative variable) and “wastewater treatment techniques” (qualitative variable). Wastewater treatment extracts pollutants, neutralizes coarse particles, eliminates toxicants, and kills pathogens to provide clean water for drinking and other uses. Wastewater treatment eliminates waste by ensuring that dirty water that would go to waste is converted into valuable products, including energy, clean water, and fertilizers. Wastewater treatment also provides sufficient nutrients that can increase crop yield if used for agricultural purposes. The study has found that wastewater treatment prevents exposure to potentially harmful chemicals that can cause serious diseases. The recovery of energy from wastewater has been described as one of the most sustainable ways of achieving a sustainable energy supply. However, the study has also found various challenges that municipalities may face when implementing wastewater treatment facilities. Some of the challenges include inadequate staffing, excessive energy use, sludge protection, and the need for large pieces of land for the facilities.

The paper argues that sustainable resource management can be achieved by reducing the waste of water, increasing the supply of clean water, converting waste to energy, developing sustainable cities and communities, and responsible consumption and production. It is essential to acknowledge that these elements are interconnected and contribute to the overarching SDG 6. By effectively managing water resources, promoting water conservation, and implementing sustainable waste-to-energy solutions, it is possible to progress towards achieving universal and fair access to clean water and sanitation for all. The first approach to sustainable resource management is reducing the waste of water. This study has found that water is the most available commodity on the planet but most of it is inaccessible to nearly 36% of the global population. The research has also found that most of the water used at home and in industries usually goes to waste. Building wastewater treatment facilities is the first step towards minimizing waste and ensuring what would have been lost goes back to circulation. Wastewater treatment facilities can produce a sufficient amount of water to support cities and suburban populations that are facing risks of water scarcity. Additionally, wastewater treatment reduces the potentially harmful environmental effects of discharging effluents into rivers, lakes, or oceans. Even landfills do not provide safe havens for discharging wastewater or sludge.

Increasing the supply of clean water would minimize scarcity and reduce pressure on natural resources. Sustainable resource management demands that supply should always exceed demand to minimize the potential depletion of natural resources. Wastewater treatment enhances the supply of clean water for both home and commercial use. Nonetheless, the process of obtaining clean water from wastewater can be costly and involves the use of technologies to minimize exposure to micro-organisms that can be harmful to health. The minimal pressure on natural resources ensures that there is sufficient water available to meet the needs of current and future generations. This will also protect millions of people around the world from being exposed to various dangers associated with drinking contaminated water. An adequate supply of clean water is also needed for maintaining high standards of hygiene in urban areas, especially in informal settlements where congestion creates opportunities for the spread of diseases associated with poor sanitation.

However, there are challenges that the municipalities should address to enhance adequate wastewater treatment. For instance, wastewater facilities should convert most of the solid organic materials into biomethane for powering the facilities and reducing dependence on external sources of energy. This will help in increasing the current conversion and consumption rate to more than 50% of the facility. Most wastewater treatment facilities can power about 50% of their plants using internally generated energy. Nevertheless, there is a need for these facilities to reach 100% to minimize any need for electricity as the primary source of energy. The use of technology should be a top priority for wastewater treatment. Investments in advanced technologies will improve data collection, real-time monitoring of the facility, and making timely interventions. Data management is also a crucial aspect of sustainable resource management since it provides accurate information to support decisions.