Improving Composting for Carbon Gains
A new process developed and trailled by Veolia in the United Kingdom increases compost recovery rates by around a quarter.
Prior to the new process, physical contaminants such as plastics and metals that had been mistakenly discareded by customers prevented a significant volume of green waste from being processed by the company and also resulted in oversize either occupying storage space within processing plants or having to be sent to landfill.
The new treatment method follows a million pound investment in a bespoke fixed cleaning line to remove contamination from compost oversize at four sites in the South of England, and uses a novel procedure to transform material into “clean” (e.g., PAS100 approved) wood product mulch for gardening and landscaping, or renewable biomass fuel for electricity and heating that replaces virgin alternatives such as woodchip and bark.
More effective processing has wider environmental ramifications, in turn, including reducing the number of trees that are felled for wood products – with the new process also removing contamination from composting sites and enhancing the quality of compost spread to land.
The effectiveness of the new process also makes composting sites significantly more efficient and lowers disposal costs as the impact of greenhouse gases. To date, more than 55,000 tonnes of contaminated compost oversize has been processed utilising the new method, with Veolia plants now seeking alternative uses for all contaminants removed in a bid to achieve zero waste-to-landfill.
Veolia currently processes over 500,000 metric tonnes of green and food waste every year which is supplied by a nationwide network of 11 composting sites that produce over 250,000 tonnes per year (or the equivalent to 12 million bags).
Chief Operating Officer, Donald Macphail, comments: “Composting sites provide the perfect example of a circular economy, and the need to efficiently process this material is likely to increase with the prospect of green waste becoming free to collect and on a more regular basis, as pledged in the government’s Resources and Waste Strategy
“By backing this new innovation we have increased the effectiveness of operations and will provide additional high quality sustainable wood mulch and renewable fuels. This will help horticulture and renewable energy generation, and is another key step that we are taking to reduce environmental impact and advance towards a lower carbon economy.”