Veolia has demonstrated a new way of treating the 25% of green waste sent for disposal or recomposting.

Veolia currently processes over 500,000 tons of green and food waste annually from a nationwide network of 11 composting plants that produce over 250,000 tons per year.

Previously, around 25% of green waste was oversized after composting, as some green waste bins contain physical contaminants such as plastic and metal that were incorrectly disposed of by customers. Even after careful processing, this contamination ends up in the compost oversize, the larger, woody fraction that remains after the valuable compost product fraction has been removed. If a site runs out of storage space or is too contaminated to be recycled, landfill costs are incurred, which in turn contributes to greenhouse gas emissions.

The new process required an investment of £ 1 million (€ 1.16 million) in a bespoke fixed cleaning line to remove the contaminants from the 30,000 tonnes of oversized compost produced annually at four locations in the south of England. This converts the material into a clean wood product like PAS100-approved mulch for gardening and landscaping or a renewable biomass fuel for electricity and heating that replaces new alternatives like wood chips and bark.

By doing this efficient form of processing, these products can reduce the number of trees felled for wood products, Veolia said, and the process also removes contaminants from composting sites and improves the quality of the compost that is spread on the land.

Veolia said the process means composting facilities will be much more efficient, disposal costs will be lowered and the impact on greenhouse gases will be reduced. To date, more than 55,000 tonnes of contaminated oversized compost has been processed this way and the facility is seeking alternative uses for any pollutants removed in order to achieve zero landfill.

Donald Macphail, Veolia’s Chief Operating Officer of Treatment, said, “Composting facilities are the perfect example of a circular economy and the need to process this material efficiently is likely to increase with the prospect that green waste can be collected for free, like more regularly pledged in the government’s resource and waste strategy.

“By supporting this new innovation, we have increased the effectiveness of the operation and will offer additional high quality sustainable wood mulch and renewable fuels. This will help horticulture and renewable energy generation and is another important step we are taking to reduce our environmental footprint and drive a lower carbon economy. “