SYDNE Y WAT ER
THE ROLE OF DESALINATION IN by Annabelle Powell, Journalist, Utility magazine
Australia is projected to see up to ten per cent less rainfall across the south of the country by 2030, and 20 per cent by 2050. Alternative water sources, such as desalination, will play an increasingly vital role in providing the population with fresh water as we face the impacts of climate change.
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esalination is the process of removing the salt and impurities from seawater to make it drinkable. Desalination facilities withdraw enormous amounts of seawater through large pipes along or beneath the seafloor, which is then processed and treated to make it safe for consumption. Desalination plants operate independent of rainfall, and with the high risk of events like heat waves, bushfires and cyclones gaining intensity in the coming decades, desalination plants can provide a critical backup supply. Following the devastating effects of the Millennium Drought – Australia’s worst drought in living memory – concern rose that the country could run out of fresh water. Six major desalination plants were constructed across the states following the Millennium Drought, with the largest in Victoria, the state hit hardest by the dry conditions. As Australia’s droughts become longer and more frequent, the existing desalination plants may have to function at a higher capacity than they are already. In addition, new plants continue to be planned and developed in coastal cities around the country.
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UTILITY • FEBRUARY 2022
FROM SEAWATER TO DRINKING WATER There are two main methods that are used to produce desalinated water: distillation and membrane processes. • Distillation: This process occurs naturally through evaporation or through very simple methods such as boiling salty water and condensing the steam. Commercial desalination plants using this process have been in operation for decades • Membrane processes (reverse osmosis): Currently, the more widely used method relies on a semipermeable membrane with microscopic pores that separate bacteria, viruses, salt and other impurities leaving only fresh water. Most desalination plants built recently in Australia use reverse osmosis Around 40 per cent of the water that goes through the desalination plant comes out as fresh drinking water. The remainder, known as brine, is pumped back into the ocean. Drinking water produced by desalination plants is monitored and tested in the same way as water from a filtration plant and must meet the standards of the Australian Drinking Water Guidelines (2006). WWW.UTILITYMAGAZINE.COM.AU
