Anaerobic digestion (AD) is a closed process that uses natural processes to break down organic materials. It produces biogas which can be burnt to generate renewable energy and a compost product called digestate.
Because AD does not have any by-products that go to waste, it is considered one of the better processing treatments. And unlike standard composting, whether in windrows or in-vessel, it captures that gas that is produced as organic materials break down, rather than releasing them to the environment. The gas itself is roughly 60% methane and 40% carbon dioxide; the high methane level is what makes it so ideal to use straight away in a range of technologies for producing renewable energy.
Anaerobic digesters can use a range of different organic feedstocks. They have been used for decades by the waste water industry for processing sewage sludge. More recently they are being used on farms to process slurries. AD is occasionally run in the UK using energy crops, such as maize silage, however this is more common in mainland Europe in countries such as Germany. Finally, and most prominent in recent years, have been the crop of AD plants built to process food waste collected from households. This is the area in which Low and Behold predominantly works, as we help local authorities and AD operators in the feasibility and planning stages of development. Because of our extensive brokerage experience, we are able to identify and map feedstocks from households, but also from paying commercial operations, such as the retail and food industries.
To find out more about how AD works, there is a short film below.
Thanks to metnet for creating this film.