WRAP Review: Technologies to optimise the value of digestate

The Waste and Resources Action Plan (WRAP) have published a review of various technologies which can optimise the value of digestate. The review includes descriptions of the technologies, a comparison of the prior status of the technology (based on the 2015 WRAP Report: optimising the value of digestate and digestion systems) to the current status, and various examples of the applications of the technologies. In addition, the review gives limited consideration of whether a technology is at a commercial stage or a pre-commercial stage.

The use of anaerobic digestion to treat food waste and other materials is now a well-established technology in the UK. The industry has grown over the last 10 years to have the capability to treat millions of tonnes of separately collected food waste from our homes, factories and businesses. This provides us with renewable electricity and gas which are a vital part of the UK transition to lower carbon energy sources.

However, the AD process also generates a nutrient rich digestate product. This is currently applied to our agricultural land as a valuable fertiliser, but industry, regulators and policy makers are now increasingly aware of a number of issues that could compromise markets for digestates going forwards such as plastic contamination and high levels of potential ammonia emissions when spread, and there is a real need to consider how to make digestate into a higher value product that is easier for operators and farmers to  handle and use.

In 2020 Wrap updated the 2015 work to look again at the technology that is potentially available to treat and add value to digestate. The resulting brief report summarises a number of technologies that have emerged and indicates where those have now reached commercial viability and where they still require some work to bring them fully to market.

The review can be read in full here.