The paper offers a brief description of Davyhulme Sewage Treatment Works, which serves the City of Manchester.
The Works, the largest in North West Water area, is regionally of strategic importance. It influences Authority policy in sludge disposal and has a significant environmental impact on the Mersey Estuary.
During the period 1983/1985 a new anaerobic digestion plant was constructed at the works. In conjunction with this scheme, an energy saving project was designed to fully utilise all the gas produced and generate electricity. The plant uses spark ignition engines with the provision of waste heat utilisation, and operates in parallel with existing dual fuel engines.
The paper describes this plant and details operating experiences over the first year and a half, exploring how energy has been saved to the point where the works can be almost self sufficient in electricity production.
It is now intended to extend the scheme further, so that the works becomes a nett exporter of electricity, and the paper outlines the design of this second stage.
Total power savings of some ₤700,000 pa have already been achieved and it is hoped to increase this to over ₤1,000,000 pa on completion of the second stage.