Policy paper

Environment Agency strategy for safe and sustainable sludge use

Updated 1 August 2023

Applies to England

We reviewed the current regulatory regime for sludge treatment, storage and use. We looked at the advantages and disadvantages of 4 options.

The option we selected will bring sludge and septic tank sludge into the Environmental Permitting (England and Wales) Regulations (EPR).

The Sludge (Use in Agriculture) Regulations (SUiAR) will no longer be needed.

1. How sludge can be used

Sewage sludge is the residual solid waste left over from the treatment of urban waste waters.

We use the term sludge as defined in the SUiAR. The water industry uses the term biosolids for treated sludge. The Water Services Regulation Authority (Ofwat) use the term bioresources for materials that contain sludge.

Sludge is made up of domestic and industrial effluents and surface water run-off. It mostly comes from waste water recycling centres (sewage plants). Some of it comes from private treatment such as package treatment plants or septic tanks.

Sludge contains useful levels of organic matter and plant nutrients. It can also contain chemicals and pathogens that could risk human health and the environment.

In most circumstances, the most sustainable option is to recycle it to agricultural land as organic manure.

An organic manure is fertiliser which comes from animal, plant or human sources. Organic manures commonly used in agriculture include:

• animal manure or slurry
• compost
• anaerobic digestate
• biosolids and septic tank sludge

Sludge can provide beneficial amounts of organic matter and nutrients to the soil. It is important to manage sludge properly to make sure:

• sludge treatment, storage and uses are sustainable
• risks to the environment, soil, plants, animal and human health are understood and addressed
• farmers and land managers can safely spread it to benefit land

If sludge is not correctly managed and used to benefit soil, it needs to be disposed of. For example, by incineration or to landfill.

We want sludge to continue to be used as a beneficial resource.

2. Our role in sludge use

Our overall role is to protect and improve the quality of air, land and water in England.

We are the environmental regulator for the supply, treatment, storage and use of sludge through the Urban Waste Water Treatment Directive (UWWTD), EPR, and SUiAR.

As part of our role we:

• provide technical advice to government on sludge and develop materials to land (M2L) policy
• work with others with a sludge management role – these include Ofwat, the Food Standards Agency, local authorities, non-government organisations, industry and land managers

We review and assess the effectiveness of our regulatory activities. We will promote the need for change if we believe it necessary. This will allow us to manage risks and push for environmental improvement.

3. Why change is needed

We need to make changes because:

• many current sludge practices do not fit with the SUiAR
• the current regulatory regime is complex
• there have been changes to the supply chain
• there have been changes to treatment processes, with a greater focus on the energy value of sludge
• new hazards are emerging
• there have been complaints, pollution incidents and poor management practices involving septic tank sludge

You can find further details about why change is needed in section 9. Reasons for change.

4. Purpose of the strategy

The purpose of the strategy is to enable safe and sustainable sludge use on land.

We want to contribute to the Department for Environment, Food & Rural Affairs’ (Defra’s) and Ofwat’s plans.

Defra’s 25 year environment plan reflects the need for this under:

• using and managing land sustainably
• increasing resource efficiency
• reducing pollution and waste

Ofwat’s water 2020 plans are looking at the transport, treatment, recycling and disposal of sludge derived from wastewater. They want to change the view that this is an inconvenient waste. They see it as an opportunity to benefit the economy and the environment.

5. Objectives of the strategy

Our business plan includes 2 aims:

1. Our investment choices deliver 75% of water at good status, and land and soil that is healthy and productive.
2. We have a priority to enable water companies to meet their environmental obligations through clear guidance and partnership working, assuring delivery and taking action when required.

We will develop the sludge strategy to achieve these aims.

6. Principles of the strategy

The 3 main principles are:

1. Modernise and clarify the regulatory framework.
2. Develop a consistent approach with the water and waste industry.
3. Identify and assess emerging risks.

6.1 Modernise and clarify the regulatory framework

We aim to be a risk-based, outcome-focused and effective regulator. We aim to give industry and the public confidence that sludge is being managed correctly and safely.

To achieve this we will:

• review the current regulatory framework
• provide clarity to define what is acceptable
• work with others on the approach we will take
• update the current regulatory framework

6.2 Develop a consistent approach with the water and waste industry

Part of our role is to be a fair and reasonable regulator. This strategy must:

• harmonise the regulatory framework for operators who treat, supply, store and use waste organic manures
• create consistency across the waste and water industries
• provide clarity on the use of sludge in England
• have a charge funded approach and apply the ‘polluter pays’ principle
• align with water industry funding cycles
• ensure coordination with Wales, Northern Ireland and Scotland

6.3 Identify and assess emerging risks

Modern sludge practices may harm the environment. To maintain industry and consumer confidence, we need to demonstrate that any new hazards are controlled. See section 9.5 Hazards.

7. How we will make the changes

We looked at the advantages and disadvantages of these 4 options for regulatory change:

1. Do nothing.
2. Revise the SUiAR.
3. Use existing EPR regulatory tools.
4. Evolve EPR regulatory tools.

7.1 Develop option 4

Our decision is to develop option 4. We will evolve EPR regulatory tools.

See section 10. Other options we considered for details of why we did not select options 1 to 3.

We selected option 4 as it has many advantages. It will use existing frameworks with some revision to the permitting process.

This will enable greater flexibility for the operator. It will put sludge regulation in line with how we control other types of organic manures.

We will keep the most appropriate parts of the SUiAR and the current EPR mobile plant permit regime.

The advantages of option 4 are that it:

• provides an opportunity to make sure human health and the environment are protected
• is modern risk-based regulation
• reduces regulatory costs and burden through development of an assurance scheme – this provides the ability to include the concept of earned recognition as defined in the Farming regulation task force implementation: earned recognition plan
• provides consistency across the bioresources sector
• continues to allow co-treated wastes to be spread under a consistent regime
• removes barriers to co-treatment
• would be charge funded
• prevents the spreading of untreated septic tank sludge
• allows industry innovation
• allows for flexible regulatory intervention along the supply chain, from the sludge producer to the final user
• is within our remit to use the existing EPR framework
• means we do not need a time limited regulatory position statement (RPS) – for example, we can withdraw Waste codes for sewage sludge materials: RPS 231
• combines spreading and storage activities and harmonises regulatory responsibility
• mitigates disruption of the current EPR scheme to the agriculture sector

The disadvantages are that:

• the revision of the mobile plant permitting regime has implications for the wider M2L sector
• it will need time and resource

This option will provide clarity, consistency and simplify the current complex regulatory framework. See section 9.2 Complex regulatory framework.

7.2 How we will evolve EPR regulatory tools

We will develop the existing EPR framework to provide regulatory tools for using sludge and materials containing sludge.

We will transfer the regulation of sludge spreading into this evolved EPR framework. Once we have done this, the SUiAR will no longer be needed.

These tools, including environmental permits, will provide:

• risk-based and outcome-focused regulation
• consistency across regimes
• the flexibility to adapt and scale the controls on current waste management practices

To evolve these tools we will:

• continue to work with Defra, Water UK, the waste industry and others to develop the strategy
• aim to submit a request for legislative change to revoke the SUiAR
• work with the water and waste industry to explore the principles of earned recognition by developing an industry-led assurance scheme
• continue to protect human health and the environment
• reduce the regulatory burden where possible

We accept concerns that an immediate transfer to the current mobile plant permitting and deployment system would present challenges for the water industry.

We will:

• commit to review and evolve the permitting regime to create a more flexible scheme
• account for the operational needs of all operators and provide the required level of control to manage the potential environmental risks
• look at how the assurance scheme can work to support us and limit the increase in costs and regulatory burden to industry

7.3 What a new regulatory framework might look like

Here are the aims of the new regulatory framework.

Achieve environmental improvement

Our aim is to reduce the risks and improve performance for the beneficial use of sludge.

This will:

• lead to an improved perception about the use of sludge
• encourage producers and operators to produce and supply treated material that will benefit soil
• encourage best practice spreading activities to maximise nutrient availability and minimise risks to the environment
• create a framework that allows for new and emerging science and technology

Where possible, we will aim to reduce costs and regulatory burden.

Risk-based and outcome-focused regulation

We will use a risk-based, proportionate and outcome-focused approach. This must:

• be appropriate to the level of risk
• be mindful of practicalities
• not result in unnecessary costs to industry

Clear and consistent regulation

The new framework must be clear and consistent. This means it must be definitive and not allow for misinterpretation. It must be within the scope of the regulations. There must be clear links to other regulatory requirements. These include:

• Industrial Emissions Directive (IED)
• Reduction and Prevention of Agricultural Diffuse Pollution (England) Regulations 2018, also known as the farming rules for water
• biowaste treatment permitting
• trade effluent controls

Charge funded regulation

The new framework must be appropriately funded.

This will enable proper determination of permissions and a robust risk-based compliance scheme.

Retain controls that are still effective

We will take the most effective and useful parts of the SUiAR and EPR mobile plant permitting to develop the new framework.

Provide continued stakeholder assurance

The new framework must be thorough and robust. To do this we will ensure that:

• the risks of using sludge are understood and managed
• sludge use ensures soil health and is supportive of the principles of a circular economy

Flexible regulation

The new regime must be flexible. We will make sure it:

• allows commercial innovation and the exploitation of new markets to satisfy Ofwat
• addresses operational requirements of sludge producers, such as flexibility in the supply and use of treated sludge

Targeted regulation

We will identify appropriate points of regulatory intervention and testing. We will consider:

• upstream sludge treatment such as at the sewage treatment works and through trade effluent controls
• storage and pre-spreading control
• post sludge treatment testing
• soil testing and improved record keeping

8. Plan of action

We will progress this strategy in line with the Regulators’ Code.

This includes for example:

• identifying the need for business impact target assessments
• developing a compliance methodology to support the new permits
• producing a new cost model to inform a new charging strategy

To progress the strategy we will help form groups to work together. The groups will:

• review and evolve the mobile plant permitting regime
• look at which parts of the SUiAR can be used
• provide the necessary evidence for Defra to change the legislation and revoke the SUiAR
• work with industry to develop an assurance scheme
• aim to better understand septic tank sludge and propose recommendations for improved sludge management

8.1 Proposed groups

The proposed groups are:

1. EPR and SUiAR review and revise group.
2. Legislative change group.
3. Assurance scheme group.
4. Septic tank group.

We will be a part of all of the groups.

EPR and SUiAR review and revise group

This group will review the EPR framework and SUiAR. It will create a new EPR based regulatory framework.

Membership will also include:

• Water UK – industry technical experts
• Biowaste regulatory forum – a trade group from the bioresources sector

Legislative change group

We will work with Defra on the required legislative changes to support the strategy.

Assurance scheme group

This group will produce recommendations for an assurance scheme to support the regulation of sludge treatment, storage and use.

Membership will also include:

• Assured Biosolids Limited who run the Biosolids Assurance Scheme (BAS)
• other relevant groups

Septic tank group

This group will look at current industry practices for septic tank sludge spreading direct to land. It will characterise the potential environmental risks and propose new requirements for treatment and spreading.

Membership will also include:

• waste industry
• Water UK

9. Reasons for change

Details of why change is needed.

9.1 Sludge (Use in Agriculture) Regulations

The SUiAR were introduced in 1989 to enact the European Commission Sludge Directive 1986.

They enable the spreading of sewage sludge and septic tank sludge to agricultural land. They are supported by the sewage sludge in agriculture: code of practice.

They do not take into account:

• modern risk-based regulation
• the chemical complexity of current sludge
• the potential environmental impact such as from new hazards
• changes in the management of sludge, from its treatment through to final use when recycled to benefit land

The SUiAR still has many good features but they now struggle to provide a usable regulatory framework.

9.2 Complex regulatory framework

The current regulatory framework for sludge treatment and use is complex. It involves a number of separate pieces of legislation.

These include the UWWTD, EPR and SUiAR.

They are not necessarily consistent with each other.

The SUiAR controls are fixed in legislation. We cannot amend them without a change in the law. They are also limited in scope as they only apply to the supply and use of sludge on certain types of agricultural land.

In 2001, the water industry introduced the voluntary safe sludge matrix which is available on the Biosolids Assurance Scheme website. This placed further pathogen controls on the use of sludge in agriculture. The water industry committed to phase out spreading untreated sludge to agricultural land. This and other water industry initiatives are now included in the BAS.

EPR controls apply to the:

• storage of sludge on agricultural land
• storage or use of sludge on non-agricultural land such as land that is used for energy crops

EPR controls also apply to the storage and use of mixed or co-treated materials that contain sludge.

The bioresources sector is now more commercially viable. This has led to:

• different regulatory approaches for the waste and water industries – such as a contrast between the regulation of sludge use and other bioresources
• the previously distinct boundary between the water and waste management sectors becoming less defined
• a lack of regulatory clarity in sludge management controls

To address the level of complexity, we produced a short-term RPS.

RPS 231 allows common industry practices that are inconsistent with the SUiAR to continue.

9.3 Changes to the supply chain

The SUiAR were designed to control the sludge supply chain. In 1989 this was considered to be short and linear. Water companies produced and treated their own sludge. It was then supplied and spread locally.

Ofwat provided a simple illustration of this. For details see figure 2 in: Sludge treatment, transport and disposal – supporting evidence and design options.

The supply chain is no longer short and linear.

From where the sludge is treated to where it is spread, can now involve long distances and third party contractors. The contractors, who can also be sludge producers or waste management companies, may handle, treat, store and spread the sludge that is produced by others.

9.4 Changes to treatment processes

Treatment processes have evolved. There is now a focus on the energy value of sludge via the production of gas through anaerobic digestion.

Water company treatment operations have evolved. Some are incorporating activities that are challenging the SUiAR definitions of residual sludge and treated sludge. The IED also applies to sludge treatment activities carried out by the water industry. This brings in further requirements.

Water industry interests include co-treatment of sludge with other waste streams. This can improve gas production or take advantage of commercial opportunities. Third party non-water company operators are also showing increased interest in the sludge market.

9.5 Hazards

The chemical complexity of the incoming sewage has changed, as has our understanding of the emerging risks associated with this complexity.

The SUiAR mainly control metals. These are referred to as potentially toxic elements. Metal loadings from industrial sources may have reduced, but there are new hazards. These are:

• organic and inorganic chemicals
• anti-microbial resistance
• micro-plastics

We will continue to work with the water industry and others on how to assess these hazards.

We aim to understand and assess these using the UK water industry research Chemicals Investigation Program. This includes specific investigations which target sludge and the fate of these substances passing through a waste water treatment works.

Other hazards include a variety of chemical inputs from domestic and run-off sources. A 2019 European Commission report Digestate and compost as fertilisers: risk assessment and risk management options, highlights some of the potential hazards contained within sludge or sludge containing composts or digestates.

As 96% of UK sludge is recycled to land we must:

• identify and understand these risks
• have management systems in place to mitigate them

9.6 Septic tank sludge

The SUiAR allow the spreading of untreated septic tank sludge to agricultural land.

These controls now appear insufficient to address the complaints we receive. These relate to:

• inappropriate sludge being spread
• poor spreading management

Recent case law has highlighted that septic tank sludge may now be unsuitable to directly spread to land. It can be necessary to do pre-treatment to remove physical contaminants.

Some of the hazards from waste water in water company derived sludge are also likely to be found in septic tank sludge via domestic effluent.

10. Other options we considered

We looked at the advantages and disadvantages of 3 other options. These were:

1. Do nothing.
2. Revise the SUiAR.
3. Use existing EPR regulatory tools.

10.1 Option 1: Do nothing

Continue to regulate and control the use of sewage and septic tank sludge through the separate the SUiAR and EPR regimes.

The only advantage of option 1 is that no effort would be required to bring changes into effect.

Disadvantages are:

• inadequate recognition of the potential hazards in sludge – does not allow us to make improvements to ensure protection of human health and the environment
• industry cannot innovate and change their business models easily with fixed regulatory controls
• continued inequality with the rest of the bioresources sector
• current industry practices for sludge treatment may be incompatible with the SUiAR without a RPS
• untreated septic tank sludge will still be spread to land
• reliance on grant-in-aid to regulate sludge activity
• no visible compliance activity
• creates risk if challenged on the confidence in using sludge on land
• no opportunity to use co-treated materials

Doing nothing is not an acceptable option.

10.2 Option 2: Revise the SUiAR

The advantages of revising the SUiAR are that it would:

• provide improved regulatory controls
• provide an opportunity to ensure protection of human health and the environment
• provide a charging scheme
• create a more modern framework
• prevent spreading or disposal of untreated sludge
• combine spreading and storage and harmonise regulatory responsibility
• enable more confidence in the use of sludge on land

Disadvantages are:

• it is not within our remit to change the SUiAR
• maintains regulation inequality in the bioresources sector
• does not allow consistent regulation with the waste management sector
• does not allow for the co-treatment of sludge and other waste

Major revisions to the SUiAR could provide the necessary environmental and regulatory improvements.

However, this would not enable the co-treatment of wastes or clarify issues over the definition of a sludge producer.

Revision of the SUiAR to incorporate these changes would create a parallel regime to the existing EPR. It would still result in complex regulation.

10.3 Option 3: Use existing EPR regulatory tools

Transpose sludge use into EPR and use the current mobile plant permitting regime.

Advantages are that it:

• provides an opportunity to ensure protection of human health and the environment
• provides consistency across the bioresources sector
• continues to allow co-treated wastes to be spread under a consistent regime
• uses an existing framework – requires minimal effort
• would be charge funded
• prevents spreading of untreated septic tank sludge
• allows industry innovation
• is modern risk-based regulation
• is within our remit to use EPR
• combines spreading and storage and harmonises regulatory responsibility

Disadvantages are that:

• feedback received from the water industry on the current EPR mobile plant permit and deployment regime, is that it is too rigid for the supply of sludge to agriculture
• it complicates Sludge Directive reporting

This seems to be the most effective and obvious solution. It could provide a consistent regulatory framework.

However, we listened to water industry concerns that the current mobile plant permitting regime is too rigid.

It does not give them enough flexibility to manage farmer relationships for sludge to land operations.