Anaerobic digestion (AD) is an increasingly popular food waste treatment option turning waste into renewable energy, biogas. The last seven years have seen an unprecedented growth in the number of AD plants throughout the UK, rising from less than 50 in 2009 to 381 today (excluding the water sector).
A fifth of these plants (79) process food waste, turning this valuable resource into renewable energy and biofertiliser (digestate). In December, it is estimated that 230,000 tonnes of additional food waste is generated in the UK. If this extra waste was sent to AD, it would create 124 MWe of energy – enough to power 220,000 homes throughout December, or a city the size of Southampton.
While the priority for food businesses should always be food waste prevention and minimisation, the increased complexity and uncertainty around Christmas ordering and production schedules means that an increase in food waste at this time of year is inevitable. Each Christmas, two million turkeys, 11 million potatoes, 17 million sprouts, 12 million carrots and 7.5 million mince pies are wasted, as shopping habits change and consumption rises. The cost of this additional festive food waste to the UK economy is an eye-watering £64m per year. But not only does this increase in food waste impact on food firms’ profit margins, there is also an environmental price to pay – leaving food waste to rot in landfill causes the release of methane into the atmosphere, a gas with 25 times the global warming potential of carbon dioxide.
Once food is no longer fit for human consumption, AD is the best treatment option – a fact which is recognised in the waste hierarchy and transposed into UK law through The Waste (England and Wales) Regulations 2011. Sending food waste to an AD (or biogas) plant significantly lowers greenhouse gas emissions compared to landfill and incineration, and is a waste treatment option that is quickly becoming a favourite of food manufacturers, producers and retailers. And it’s not solely down to the associated ‘green halo’ that comes from doing the right thing for the environment; today’s modern AD plants are a flexible, cost-effective and hassle-free way to treat waste food.
As waste volumes increase during the festive period, waste hauliers’ capacity fills up fast. Food companies can suddenly find themselves faced with a mountain of surplus Christmas food waste that their usual waste carrier is unable to take – or will only treat for a vastly inflated fee. No company wants its waste hanging around for longer than is absolutely necessary, and some sites also have the additional issue of waste permits, which may prohibit them from keeping their waste on site for any length of time. Food firms should plan ahead for an alternative place to send their additional Christmas food waste and seek out their local AD plant.
Last Christmas, food businesses based in London, Essex, Hertfordshire, Bedfordshire and Cambridgeshire sent thousands of tonnes of mince pies, sprouts and turkeys to London-based AD plant Willen Biogas. ¬“We helped a number of local food companies with their last-minute Christmas waste problems, arranging collection, transport, depackaging and treatment of their food waste at short notice,” says Willen Biogas Chairman, Adrian Williams. “Our cost-competitive waste treatment options can be used for one-off loads or we are happy to discuss longer term contracts depending on our client’s requirements.”
Located just off junction 25 of the M25, the state of the art, modern 1.5 MW AD plant processes around 60,000 tonnes of food waste every day – and has capacity to handle any local Christmas surplus. Fitted with sophisticated front-end depackaging equipment, it can handle all types of food waste, including packaged, (with the exception of palletised loads) and accepts deliveries with as little as 24 hours’ notice.