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What is Anaerobic Digestion and why should it be encouraged?


Anaerobic digestion is the conversion of biodegradable material in sealed vessels in the absence of oxygen by a consortia of bacteria and Archaea from which a valuable biogas and a digestate are produced. This biogas is collected and typically utilised as a source of energy. Digestate from the process can be utilised as a fertiliser (replacing mineral fertiliser) and as a soil conditioner. Alternative uses for biogas and digestates are currently being evaluated.

AD has already been implemented across many countries in Europe to treat biodegradable organic wastes such as source segregated food waste, organic fraction of municipal solid waste (OFMSW), biodegradable commercial and industrial (C&I) wastes, sewage sludges, agricultural residues and animal slurries as well as to generate energy from energy crops. The UK has already seen a significant deployment of anaerobic digestion technology for treating sewage sludge and some progress is being made recently in the establishment of this technology for treating other organic materials.

Anaerobic digestion is an attractive option for Wales and the UK as it can contribute towards meeting targets for waste recycling and diversion of organic wastes from landfill, the requirement to pre-treat organic materials prior to disposal, targets to reduce greenhouse gas emissions and the requirement to generate renewable energy.