Last month a parish councillor visited Agrivert’s ‘anaerobic digestion’ facility in Wallingford, which processes 20,000 tonnes of food waste from our area each year.
Caddy bags are delivered by lorry, then fed into a machine which mechanically removes the waste from its packaging. It is then macerated and digested anaerobically in large sealed tanks. This process creates enough energy to power 4,800 homes (via biogas, converted in gas engines into electricity). It also creates enough nutrient-rich fertiliser to cover 2,500 acres of local farmland. The whole process captures 4.5 million m3 of methane every year, which is equivalent to removing 71,000 cars from the road.
There were two clear messages from the visit: firstly, there is no benefit to using compostable bags in your food waste bin (the process isn’t warm enough to compost the bags, and the plant is designed to remove all packaging, so you might as well use whatever bag you have to hand, including any plastic ones lurking in your cupboard). Secondly, there is still a huge amount of food waste going into black bins in our area. The waste from our black bins is incinerated (an energy-hungry process), whereas this plant converts our waste and effectively recycles it for a new purpose, so please do your bit and chuck your food waste in a caddy!