What is Anaerobic Digestion?

July 8, 2022

Anaerobic digestion is the process by which organic matter such as animal or food waste is broken down to produce biogas and biofertiliser.

The AD process begins when biomass is put inside a sealed tank or digester.

Naturally occurring micro-organisms digest the biomass, which releases a methane-rich gas (biogas) that can be used to generate renewable heat and power; this helps cut fossil fuel use and reduce greenhouse gas emissions. The remaining material (digestate) is rich in nutrients, so it can be used as a fertiliser.

Many forms of feedstock are suitable for AD; including food waste, slurry and manure, as well as crops and crop residues. However, woody biomass cannot be used in AD because the micro-organisms can’t breakdown the lignin, the compound that gives wood its strength.