Technical note DBPAS 11: Plastics and Microplastics in Digestate Biofertiliser

The topic of plastic and microplastics in digestate is an emerging issue for the recycling of organic waste into beneficial end products.  This technical note reviews the current science and knowledge base about plastic and microplastics and the prevalence of these in digestate.  The Digestate Biofertiliser Certification Scheme (DBCS) recognises that quality limits exist for plastic content in digestate, however there are differences between countries about what amount of plastic is acceptable.  There are no regulations in any country that control the acceptable level of microplastics in digestate.  Furthermore, there is a lack of agreed standardised methodology for testing microplastics in digestate.  Interventions are available at all points in the value chain that can minimise the occurrence of plastic (and therefore microplastic) in the digestate. 

As the authors of the DBCS, the Bioenergy Association has researched the latest scientific evidence to inform the quality standards for plastic and microplastic for the biofertiliser. The findings and recommendations presented in this Technical Note represent current international knowledge and management practices for minimising plastic and microplastic in digestate.  The DBCS will continue to watch developments from around the world and in New Zealand for the most up to date information on these contaminants.