What is anaerobic digestion? Anaerobic digestion (AD) is the creation of digestate and biogas (mainly methane), through the breakdown of an organic feedstock in the absence of oxygen by micro-organisms. This process occurs in an insulated sealed container, heated between 35°C and 55°C. Organic Feedstock Almost any biomass can be processed in AD, including food waste, energy crops, crop residues, slurry and manure. Biomass waste from wood cannot be used in AD because the micro-organisms cannot breakdown the lignin. Biogas Biogas is a mixture of methane (60%) and Carbon dioxide (40%) including traces of other contaminant gases. The exact composition depends on the type of feedstock being digested. Biogas can be refined into bio-methane, which can be combusted to provide heat, electricity or both. This is achieved by removing other gases and can be injected into the mains gas grid, burned for heat, generate power, or used as a road fuel. Digestate Digestate is made from left over indigestible material and dead micro-organisms. It contains valuable plant nutrients like nitrogen and potassium. It can be used as a fertiliser