Anaerobic Digester | Codford

Clegg worked on an anaerobic digester in Codford, Wiltshire. This included the structural design, detail and project management.

These digesters work by breaking down food waste. Then producing a biogas, in this case methane, and a bio-fertiliser. The digester on this design receives 45,000 tonnes of food waste per year. This creates methane gas from two 21.5m diameter digesters. Two Combined Heat and Power (CHP) plants contains the burning gas. Thus, providing electricity, with the bio-fertiliser used as manure on nearby fields.

The anaerobic digester resides on chalk foundations. The design has to allow for fissures and swallow holes, whilst supporting 4000 tonnes of liquid for each digester.

A bund wall around the digesters comprised of a ground bearing concrete slab and sealed walls. This contains any spillages that could occur, preventing contamination of the water table.

The design of the reception building constructed a galvanized steel frame and a concrete retained bay. This stores the incoming food waste. We also designed a lagoon to pump the bio-fertiliser, so it can then collect and spread onto nearby fields.