Cronulla Sewage Treatment Biogas Project

Biogas renewable cogeneration
Location: Cronulla, NSW

Wastewater biogas

Sewage wastewater can either be treated aerobically (in the presence of oxygen) or anaerobically (oxygen excluded). The anaerobic process produces methane,which in this project is collected and used to generate renewable power. If not collected and used for power production the methane would either be flared or vented to the atmosphere with adverse environmental impacts.Methane has 22 times the greenhouse gas impact of carbon dioxide.

Project overview

The Sydney Water cogeneration project forms part of an upgrade of the Cronulla Sewage Treatment Plant. This includes upgrading the level of sewage treatment processing, improving the security of the treatment process and meeting Sydney Water's commitment to ecologically sustainable development practices.

Energy offering

The power produced by the biogas generation project displaces purchases of high value electricity from the grid. The unit will be able to provide approximately 10 per cent of the power requirements of the Cronulla Treatment plant. The unit will produce 2470 MWh of power per year.

The heat produced by the engine exhaust and jacket is recovered and used to heat the sewage sludge in the anaerobic digestion process, which assists the processing of the sludge and the production of methane for the generation unit.

Producing power "on-site" increases the reliability of supply to the plant and provides a level of sewage processing during power outages.

The plant reduces greenhouse gas emissions arising from the processing of Cronulla's sewage by 17,000 tonnes of carbon dioxide each year.

Operational

The biogas cogeneration plant is designed to utilize 100 per cent of the gas produced by the digesters and can operate 24 hours, seven days a week.