West Australia looks at five desalination options
The Water Corporation in Western Australia is looking at five options for desalination as part of its draft plan Water Forever: Directions for Our Water Future published on 9 March 2009 for public comment.The five options are:
The plan also seeks to support the recycling of up to 60% of wastewater in the Perth-Mandurah area.
The Water Corporation estimates that an additional 120 million m³ of water will be required annually by 2030 - more than 40% of current supply. By 2060, it is forecast that Perth and connected towns will need an additional 365 million m³. Some of this will be needed to replace declining rainfall and the balance to meet projected growth in demand.
The Water Corporation plans to help Perth households and businesses reduce water use and ultimately use a quarter less water. This will begin with reducing per person water use from current levels of 147,000 litres a year (L/y) to 125,000 L/y by 2030. It is hoped that this will defer the immediate need for a new water source once the Southern Seawater Desalination Plant is commissioned in 2011.
Once online, the plant will produce an additional 50 million m³/year to supply the Perth-Mandurah area. As a result of this additional supply, the Water Corporation will be able to reduce the amount of groundwater taken from the Gnangara Mound, which is currently under stress due to climate change impacts.
The Southern Seawater Desalination Plant can be doubled in size to produce another 50 million m³, most likely after 2020. The expansion could be owned, operated and maintained by the private sector.
The Kwinana Water Recycling Plant has provided recycled water to industry since 2004. The Water Corporation is proposing to expand this plant from 6 million m³/y to 10 million m³/y by 2010, subject to sufficient demand from industry. It is undertaking a three-year trial, commencing in 2009, to test the viability of this option.
If the trial is successful and groundwater replenishment has regulatory approvals and community support, the Water Corporation will develop a groundwater replenishment scheme, which will provide around 35 million m³/y of water for public water supply by 2030, enough to supply 145,000 households. In the longer term to 2060, groundwater replenishment could provide up to 115 million m³ of water, enough to supply almost half a million people.