The PAS110 specification for biofertiliser created during the anaerobic digestion (AD) process has been updated with changes to digestate stability criteria and limits on contaminants.
Under the new guidelines, published by the Renewable Energy Assurance Ltd (REAL) and WRAP, stability requirements for the digestate have been made closer to other organic materials commonly spread on land, such as pig slurry. Currently, they relate more to cow slurry.
The guidelines also tighten the limits on physical contaminants in the slurry, to increase safety and improve quality.
Operators of AD plants who meet the new standards will be able to use and trade digestate as certified biofertiliser under REAL’s Biofertiliser Certification Scheme.
REAL chief executive Virginia Graham said: “Everyone involved in AD has learned a lot about digestate as the industry has developed. Working closely with industry, we have used these lessons to improve the PAS110 for producers, end-users and the environment.
“The changes mean that more AD operators will be able to use or trade their digestate as certified biofertiliser, whilst environmental protections will be stronger than before.”
REAL is a subsidiary of the Renewable Energy Association and carries out certification and consumer protection activities to promote sustainable energy.