Delta Electricity - Mt Piper & Wallerawang
Reverse Osmosis (RO) following pre-treatment by microfiltration
Wallerawang, near Lithgow, NSW
6 ML/d at Mt Piper and Wallerawang (upgradeable to 12 ML/d)
Challenge While “blow down” water from cooling towers at NSW electricity generator Delta Electricity’s Wallerawang and Mt Piper power stations has been collected, the volume of salts retained during the cooling process has made it unsuitable for reuse without treatment. Previously this water was disposed of through licensed and controlled discharge to the environment with fresh water being continually drawn from local rivers and dams to meet on-going process requirements. Delta Electricity sought to optimise its water usage through reuse.
Solution In joint venture with UGL, Osmoflo has designed and commissioned two 6ML/d reverse osmosis plants to desalinate the collected blow down water and converted it to a quality suitable for reuse. Both plants were constructed in modular form to allow for increased capacity if required. Pre-treatment is by microfiltration. As a result of the reverse osmosis process, salinity is reduced from more than 3000 mg/l Total Dissolved Salts to less than 50 mg/ at Mt Piper and to less than 200 mg/l at Wallerawang for reuse in cooling towers. Through an operations and maintenance contract, both plants were constantly monitored from Osmoflo’s 24 hour control centre at Burton SA, utilising the company’s proprietary PlantConnect software. This ensures optimum plant performance while eliminating the need for full time operators on site.
Result Delta Electricity’s reliance on local water sources was substantially reduced and discharges of blow down wastewater to the environment practically eliminated.
Note: Wallerawang power station was closed in 2015. Mt Piper power station is now operated by Energy Australia.