Standard rules consultation: revision of standard rules for On-Farm Anaerobic Treatment Activities (SR2012_No10, SR2018_No11 & SR2023_No1)

We have reviewed the evidence provided by the Environment Agency that the cause of incidents and poor performance in England & Wales are mainly due to:

• inadequate design and poor construction standards
• lack of operational process control
• failure to have or follow an effective management system
• deficient maintenance systems
• inadequate pre-acceptance and acceptance checks, including unacceptable levels of feedstock contamination

We came to this conclusion by:

• reviewing the responses to the EA Call for Evidence consultation in 2018
• reviewing our compliance data on AD and composting sites

Recovering organic waste for soil benefit replaces the reliance on chemical fertilisers and decreases the dependence on peat.

Our objectives are to:

• increase the use of food waste as a resource
• replace chemical fertiliser through waste recovery

As set out in the government strategy for a circular economy

• “Beyond Recycling”

We will also strive to meet the government's objectives for greenhouse gases (specifically those linked to the waste sector and reducing Greenhouse Gas Emissions) as set out in their:

• Clean Air Plan for Wales: Healthy Air, Healthy
• Welsh Government Net Zero strategic plan

This sector can have a positive effect on climate change by:

• reducing the deterioration in soil quality
• capturing and storing carbon
• producing energy from AD

However, Natural Resources Wales must ensure:

• emissions are controlled, such as odour, bioaerosols, greenhouse gases and ammonia
• there is no risk to water, air, soil, plants or animals

The standard rules sets below have existing holders but are not available for new applications.  We call these 'withdrawn and archived'.

1. SR2012 No 10: on-farm anaerobic digestion facility using farm wastes only, including use of the resultant biogas (not available to new applicants), &
2. SR2018 No 11:  on-farm anaerobic digestion facility including use of the resultant biogas (not available to new applicants)

These permits are identical currently have a total of eight holders (six SR2012No10 & two SR2018 No11). They will remain ‘Withdrawn and Archived’ and not available to new applicants.

3. SR2023 No 01 – on-farm anaerobic digestion facility using farm wastes only, including use of the resultant biogas ( >100/tonnes a day)

This permit currently has three holders, one of which is non-operational. This permit is currently available to new applicants; however, we propose to Withdraw and Archive this permit so that it is no-longer available to new applicants.

We consider that withdrawing and archiving the last remaining Standard Rules set available will contribute to achieving the objectives of this consultation. 

Due to the low utilisation of this rule set, as evidenced by the minimal number of active permit holders, we anticipate a negligible impact on business.

New applicants seeking a Permit to undertake a new activity at a new site will need to obtain Bespoke permits. This will ensure that future permits are tailored to the specific operational needs, waste streams, and site setting of specific operations to ensure risks are adequately controlled and mitigated.

We have proposed amendments to the permitted activities table for AD to include:

• upgrading of biogas and injection of bio methane to the grid
• allowing pasteurised, separated digestate fibre to be composted in the open with abatement or under static aeration
• provision for safe storage of raw materials
• provision for safe storage of hazardous waste, such as spent engine oil and used carbon

In this consultation, we propose updating the site location criteria for standard rules permits to include marine conservation zones. This change is necessary because marine designations were not in place when some of these standard rules were initially developed.

We also propose to include minimum distance from sensitive receptors, designated sites, water courses and sites or habitats of principle importance where the permitted activities are considered a risk. 

Additionally, we suggest incorporating Air Quality Management Areas into the site location criteria. We recognise that stabilisation and maturation of composting digestate fibre can have a negative impact on air quality. For this reason, we propose that standard rules will not be available for operations within Air Quality Management Areas.

We recognise recovering organic waste for agricultural benefitreplaces the reliance on chemical fertilisers and decreases the dependence on peat. We want the biowaste industry to be a Circular Economy leader. However, to achieve a higher demand and market price the output material must be of consistent quality to meet customer requirements.

Therefore, although we do not propose remove any waste codes that can be accepted, we propose to specifically exclude:

• hazardous waste
• wastes containing wood-preserving agents or other biocides and post-consumer wood
• wastes containing persistent organic pollutants
• wastes containing Japanese knotweed or other invasive plant and flatworm species listed in the Invasive Alien Species (Enforcement and Permitting) Order 2019
• Livestock manures, slurries and spoiled bedding and straw from farms where animals have notifiable diseases
• pest infested waste

And propose the following additional waste types for:

• 02 01 99 - Wastes not otherwise specified – spent mushroom compost from commercial mushroom growing only

These changes only apply to SR2012 No 10 & SR2018 No 11 as they are already required by SR2023 No.1.

We propose to make changes to permits, such as including operating techniques requiring:

• Waste shall be stored for the minimum time practicable before treatment
• quarantined and rejected waste shall be stored in closed containers or covered and removed to a regulated facility within 5 days
• Incidental, non-compostable and digestible fractions are removed from the waste prior to processing to a low as practicable level.
• The operator to have a site drainage plan
• Discharges to groundwater or surface watercourses shall consist of clean water only.
• air extraction and abatement systems shall be designed and built specifically for the facility
• transfer areas shall be monitored and tankers supervised
• pressure systems shall be suitably designed, monitored and inspected
• Drying separated digestate fibre can only be undertaken in a suitably designed closed system with abatement system
• Composting of digestate fibre shall be undertaken to promote aerobic conditions
• Methane leak detection

We expect how the operator intends to comply with these rules to be detailed in the sites EMS.

We do not anticipate any additional costs, as facilities should already be applying these techniques within their management systems to comply with existing conditions and directly applicable legislation.

These changes only apply to SR2012 No 10 & SR2018 No 11 as they are already required by SR2023 No.1.

We propose changes to the design, construction, and maintenance of critical infrastructure, secondary containment, and drainage systems to meet recognised standards that protect assets and minimise the risk of failures.

Specifically, we require adherence to CIRIA (Construction Industry Research and Information Association) standards (Report 736 or an equivalent standard), all tank are fitted with level sensors and pressure systems are designed to accommodate the routine variation in gas flow, production and pressure events.

A qualified civil engineer would assess the site to validate (sign off) that all waste acceptance, storage, and treatment areas are constructed and maintained according to CIRIA or equivalent standards. We propose that the operator does this within 6 months from the date of the revised rules set being published.

If the assessment finds that the site does not meet CIRIA or equivalent standards, the site operator will have the opportunity to modify their site and submit an improvement plan to mitigate the risk. With all required works being completed within 18 months from the date of the revised rules set being published.

The operator will also be required to:

• Report on the condition of critical infrastructure.
• Include inspection and maintenance procedures (as per manufacturers’/design recommendations) in their recorded written management system.
• Provide an accurate drainage plan showing how they will prevent the risk of polluting material leaving the site.

This proposal will align the biowaste treatment sector with other waste and industry sectors, such as landfill and agriculture, which already require site validation by a qualified chartered engineer.

When facilities operate beyond their design or site capacity, several issues may arise, including problems with odour, bioaerosols, and output quality. To address this, we propose that the permit should state:

• The need to operate within the design or site capacity of the facility.
• That the operator will not accept waste unless there is capacity to treat it.
• That all incoming waste is managed to prevent uncontrolled decomposition, including monitoring and actively managing feedstock.

We propose that operators assess and detail their design or site capacity within their EMS and include how they achieve operation within these limits. 

Operators must also make provisions for the storage of finished material when the landbank is not available, ensuring adequate storage capacity whilst maintaining a freeboard of at least 750mm for liquors, leachate, and/or digestate.

We do not anticipate any additional costs, as facilities should already be operating within their design or site capacity.

These recommendations only apply to SR2012 No 10 & SR2018 No 11 as they are already required by SR2023 No.1.

A cover for slurry and anaerobic digestate stores and lagoons reduce water ingress and therefore reduces the volume of slurry or digestate an operator needs to store and spread on land. It also improves air quality by reducing ammonia emissions.

We propose that any new digestate storage lagoons designed and built following the date of the publication of the revised rules set are covered. This requirement will not apply to existing lagoons.  

These changes only apply to SR2012 No 10 & SR2018 No 11 as they are already required by SR2023 No.1.

The facility's management system sets out procedures, including staff training. It should also include a commissioning plan. This sets out how the operator will address incidents during commissioning.

The lack of, or a poorly adopted management system causes failures and non-compliance. Therefore, we propose sites will be required to submit a re-commissioning plan before re-start following any period of shut down or refurbishment. For example, following works to bring the site up to CIRIA standards.

We propose that all facilities do a Commissioning facilities and Hazard Operability Study (HAZOP) assessment or similar risk assessment to inform the requirement for critical work and maintenance. Operators will need to detail the programme of works in their management procedures.

There should be no additional cost as operators should already be doing this.

The facility's management system sets out procedures for preventing and identifying fugitive emissions. However, the lack of, or a poorly adopted management system can be the cause of uncontrolled releases of gasses that can cause odours and non-compliance. Methane releases also contribute to climate change.

Therefore, we propose operators implement a leak detection and repair (LDAR) programme to detect and mitigate release of volatile organic compounds, including methane. The operator shall undertake a minimum of annual inspections and provide an annual summary report.

Invasive non-native species (INNS) are a threat to biodiversity in Wales and as such there are regulations to prevent and minimise the impact of their introduction and spread.

Therefore, in addition to Japanese knotweed we propose enhance biosecurity measures by excluding other invasive plant and flatworm species listed in the Invasive Alien Species (Enforcement and Permitting) Order 2019.

To align with Animal Health Regulations and ensure high standards of animal and public health, we propose to exclude manures, slurries, and spoiled bedding and straw from farms where animals have notifiable diseases, as stipulated in The Animal By-Products (Enforcement) (Wales) Regulations 2014

Pests arising from anaerobic digestion activities can cause health hazard or annoyance outside the boundary of the site. Therefore, we propose an operator shall not be taken to have breached this rule if appropriate measures, including, but not limited to, those specified in any approved pests management plan, have been taken to prevent or where that is not practicable, to minimise the presence of pests on the site.

Fires can occur from poorly managed anaerobic digestion and associated storage. To reduce the risk of fire, we propose operator implement a fire prevention plan that prevents fires and minimises risks. The operator will also be required to undertake Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) assessment and maintain an accident management plan. Along with methane leak detection monitoring and permit to work procedure on AD plants.

We do not think operators will be affected by the additional requirements. The majority of sites will already have put in these measures.

This change only apply to SR2023 No.1 as they are already applies in SR2012 No 10 & SR2018 No 11.

We propose to remover the requirement for the operators to report all material leaving the site, including certified material and digestate produced from the digestion of manures and slurries only.

The reason for this change is that we do not currently have a central or uniform reporting process to collect this information. Operators are already required to record and be able to make this available to for inspection and review when requested.

In future we may review.

We do not propose any changes to the Generic Risk Assessment (GRA).