While it may sound like an unappealing bodily process, anaerobic digestion is a crucial method to create biogas for electricity generation, as well as a source of bio-fertiliser production. We thought we’d take a closer look at just what the process involves, and why it’s important in boosting the circular economy.
What is it?
Anaerobic digestion (AD) is the name given to the process by which organic materials (such as animal or food waste) is broken down in the absence of oxygen. Biogas is one of the by-products, and this gas can then either be combusted to generate heat and power, or processed to create renewable natural gas and transport fuels. A nutrient-rich bio-fertiliser is also left behind, which is used as an alternative to fossil fuel-based fertilisers in the agricultural sector.
The AD process takes place in an air-tight tank called an anaerobic digester. You can get both ‘wet’ and ‘dry’ versions of the process, with the latter using lower-moisture content feedstocks such as yard waste, while the former uses feedstocks such as manure or food processing waste.
AD has been identified by a host of organisations around the world, such as The Department for Environment, Food and Rural Affairs, Friends of the Earth and the National Farmers Union as one of the best methods of dealing with farm waste, and of recycling food waste.
For every tonne of food recycled using AD, between 0.5 and 1 tonne of CO2 is prevented from entering the atmosphere – making it a powerful tool in harnessing natural processes to cut emissions.
In the news
AD projects are underway around the world, and just this week Next Generation Manufacturing Canada (NGen) announced its partnership with organic waste developer Genecis Bioindustries. The collaboration will use AD to develop a novel biotechnology platform, which will upcycle food waste into premium sustainable plastics. Under the project, a demonstration-scale technology unit will be combined with an AD plant to convert the organic feedstock into bioplastics.
The organic plastic alternative will be used to replace plastics in industries including packaging, medicine and agriculture. Commercialisation of the technology is hoped to secure Canada’s role as a leading power in the biomanufacturing sphere.