Desalination is a secure water source that doesn’t depend on rain. Water produced by our two desalination plants makes up 48% of Perth's water supply.
How does desalination work?
Seawater desalination is the removal of salt and impurities from seawater to produce fresh water. Our desalination plants do this via a reverse osmosis process.
Seawater is passed through a pre-treatment filter that removes large and small particles. The filtered seawater is then forced under pressure through special membranes whereby the osmosis process that normally occurs in nature is reversed. The pores in the membranes are so tiny that salt, bacteria, viruses and other impurities are separated from the seawater. In essence they act like microscopic strainers. About half of the water that enters the plant from the sea becomes fresh drinking water. The salt and other impurities removed from the sea water is then returned to the ocean via diffusers, which ensures it mixes quickly and prevents the marine environment from being impacted.
The desalinated water is then subject to further treatment to meet drinking water standards before it reaches our customers.
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Our desalination plants
We operate two seawater desalination plants: the Perth Seawater Desalination Plant in Kwinana and the Southern Seawater Desalination Plant in Binningup.
Looking to the future
In late 2017 we started to look at the feasibility of new desalination plants north and south of the Swan River, one near Kwinana close to the existing Perth Seawater Desalination Plant and the other in the northern suburb of Alkimos.
At this stage there is no firm timeframe for building a new desalination plant for Perth’s Integrated Water Supply Scheme. The timing depends on annual rainfall and how fast our climate continues to dry, how much water we use each year and population growth.