Case Study
Eraring Power Station Saves Money With Water Reclamation
Challenge
Australia's Eraring Power Station, owned by Eraring Energy, needed to treat secondary sewage from the nearby Dora Creek municipal wastewater plant for recycle as high-quality boiler feedwater. The power plant was sharing potable water with 25,000 homes, resulting in an intermittent supply. Secondary sewage needed to be piped 10 miles (17 kilometers) to a sea outfall.
Solution
Siemens Water Technologies provided Eraring with a microfiltration and reverse osmosis (RO) system to treat secondary sewage and recycle the treated water to an existing deionizer. Eraring Energy saw microfiltration/RO technology as a benchmark for treating and recycling secondary sewage, and a way to substantially reduce annual potable water and demineralized water production costs. Siemens also provides service on the equipment under a service contract.
Results
- Started up in February 1995, the microfiltration/RO system is producing high-quality boiler feedwater and has turned the power station into a zero discharge operation.
- Total cost savings to the company at the end of 2002/03 were almost $3.7 million (US), with the largest cost savings in water charges and downstream ion exchange regeneration chemical costs.
- Overall, the total chemical costs for both microfiltration and RO units are just over $.01 (US) per 1,000 gallons of reclaimed water produced. Annual savings in the station's demineralizing plant are estimated at $52,000.00 (US).
- The microfiltration and RO systems at Eraring still contain some of the original installed membranes, making this the longest operation of membranes in an effluent reuse application in the world.
- Despite the varied age of the membranes, the reclaimed water produced contains far fewer impurities than the previously used potable water.
