The Scottish Environment Protection Agency (SEPA) has confirmed progress following the closure of its Call for Evidence on non-waste anaerobic digestion (AD) facilities handling more than 100 tonnes per day, which concluded on 9 January 2026.
The Call for Evidence formed part of SEPA’s preparatory work to develop a formal consultation on future permit technical requirements for large-scale non-waste AD operations. The updated framework will apply to new and existing operators carrying out this activity after 1 April 2028, marking a significant regulatory milestone for the sector.
These large scale facilities include;
- Agricultural or energy-crop-fed AD plant, where the primary feedstock is purpose-grown crops or agricultural residues
- Municipal wastewater treatment plant digesters
- Food & beverage industry process-water AD plants – e.g. breweries, distilleries, food manufacture
- Pulp & paper mill effluent AD
Evidence-based development of permit conditions
SEPA’s review assessed technical submissions and operational evidence provided by industry stakeholders, with the aim of ensuring that future permit conditions are both robust and proportionate. The regulator has confirmed that the majority of waste treatment Best Available Techniques (BAT) conclusions identified during the Call for Evidence were considered appropriate and achievable for inclusion as permit “appropriate measures” for large non-waste AD facilities.
This reinforces the importance of aligning non-waste AD design and operation with BAT principles traditionally associated with waste treatment activities – particularly in relation to emissions control, process monitoring and environmental protection.
Discharge to the water environment – a developing area
One notable outcome of the review relates to BAT 20 (discharge to the water environment). SEPA concluded that a single, uniform approach may not be appropriate in all cases. Instead, the regulator is considering different implementation options based on the capacity and sensitivity of individual receiving water bodies.
These options will be explored in more detail during the forthcoming consultation, recognising that site-specific conditions – such as hydrology, catchment pressures and background water quality – can significantly influence the environmental risk profile of a discharging AD facility.
Case-by-case regulatory approach retained
SEPA has reiterated that it will continue to take a case-by-case approach when setting permit conditions, allowing flexibility to achieve compliance without causing unacceptable impacts to either the environment or business operations. This principle is particularly relevant for existing facilities that may require phased upgrades or operational changes to meet future expectations.
The final consultation on appropriate measures and permit templates is expected to take place after the Scottish election period, giving operators time to engage with proposals ahead of the 2028 implementation date.
What this means for AD operators and developers
The direction of travel is clear: large-scale non-waste AD facilities will be subject to increased regulatory scrutiny, with a stronger emphasis on BAT alignment, emissions management and water environment protection.
Operators and developers should take proactive steps now to:
- Review existing designs and operating practices against relevant BAT conclusions
- Assess potential gaps in environmental performance, particularly in relation to effluent management and site drainage
- Understand how site-specific environmental constraints may influence future permit conditions
Early technical and regulatory due diligence will be critical to managing risk, cost and programme certainty.
How Albion Environmental can help
Albion Environmental has extensive experience supporting anaerobic digestion projects across the UK, from early feasibility through to permitting, compliance and operational support. Our services include:
- Environmental permitting and regulatory strategy, including engagement with SEPA
- BAT and appropriate measures assessments for new and existing AD facilities
- Water environment assessments, including discharge option appraisal and supporting technical reports
- Operator support and permit variation applications ahead of regulatory change
We are closely following developments in SEPA’s consultation process and can help clients position their projects to meet future requirements with confidence.
If you would like to discuss how these changes may affect your AD facility, please get in touch with our team by emailing info@albion-environmental.co.uk or by calling 01292 610428.