Scotland has not, to date, adopted the Anaerobic Digestion Quality Protocol, and this is not a requirement for digestate producers in Scotland. For biogas plants in Scotland the certification criteria are:
- BCS Scheme Rules – the Scheme Rules detail how the Biofertiliser Certification Scheme actually operates and include procedures for application to the scheme, product complaint investigation, etc.
- PAS 110 - This specification sets out the technical requirements for the AD process and production of anaerobic digestate, including the minimum quality criteria for whole digestate, separated liquor, and separated fibre.
- SEPA’s End-of waste regulatory position statement for digestate – This sets out SEPA's requirements for digestate to achieve End of Waste. This RPS introduces additional standards, reducing the levels of plastic contained within digestate; the plastic limit is 8% of current PAS 110 limits. This aligns plastic contamination limits with Quality Meat Scotland (QMS) standards.
Fully recovered digestate can be supplied, stored, and used as ‘products' in Scotland, however they cannot be supplied for use as a 'product' in England or Wales unless they are also certified compliant with the ADQP. Operators in England, Wales, and Northern Ireland can apply for End of Waste Scotland, if they are supplying, storing, and using their product in Scotland.