Water. Desalination + reuse
Issue link: https://fhpublishing.uberflip.com/i/1056083
24 In Site December 2018 Water.desalination+reuse WESTERN AUSTRALIA • Perth Seawater Desalination Plant and Southern Seawater Desalination Plant • Two facilities provide 48 per cent of state's water – or 397,300 m3/d • Rainfall down 19 per cent since the 1970s • New plants possible at Alkimos and/ or Kwinana Western Australia is the clearest desalination success story in Australia. The capital city, Perth, relies on desalinated seawater for around 50 per cent of its drinking water supplies. Climate change is the biggest challenge for Water Corporation, the main supplier of water in the state. Water Corp serves two million people in Perth, the Goldfields and Agricultural Region, and parts of the South West. May to July rainfall in the south west of Western Australia has dropped by around 19 per cent since the 1970's, statistics from the Bureau of Meteorology show. Streamflow into dams has declined even more dramatical - ly. Dams in Perth received, on average, 420 gigalitres of stream- flow each year prior to 1975; but in 2017, only 104 gigalitres flowed in, a precipitous decline of 75 per cent since the 1970s. Investment in climate-inde - pendent water sources has been crucial. Desalination was the state's biggest source of water in 2017-18, providing 48 per cent of the total requirement, compared to 40 per cent from groundwa - ter, 10 per cent surface water through dams, and 2 per cent groundwater replenishment. Water Corp eyes new plants Western Australia has two large- scale desalination plants, South- ern Seawater Desalination Plant, at Binningup — capacity 100 gigalitres a year (274,000 m3/d) — and Perth Seawater Desalina- tion Plant, capacity 45 gigalitres a year (123,300 m3/d). Now the utility is eyeing sites possibly to build two new seawater reverse osmosis plants: Alkimos, north of Perth, and Kwinana, to the south. The projects form part of long-term plans to identify climate independent sources. Because a new water source may be needed for Perth within 10 years, now is the time for consultation and investigation. If constructed, a desalination plant in Alkimos would be delivered in stages as demand increases. Initially, it might have capacity of 25 gigalitres (68,000 m3/d) of drinking water a year, and 25 gigalitres a year in the second stage. "Ultimately, the plant could have capacity of 100 gigalitres a year," says a Water Corporation spokesperson. The utility is conducting offshore geophysical and geotechnical surveys at Alkimos, and has applied for certain other, related environmental approvals. The feasibility studies for Kwinana are also investigating staged delivery. This could begin at 25 gigalitres a year (68,000 m3/d), up to a maximum capaci - ty of 50 gigalitres a year (137,000 m3/d). The studies are taking account of likely environmental, social, technical, and financial outcomes. Further applications for other additional approvals for both potential plants are expected in 2018 or early 2019. Contractors or suppliers who wish to be kept up-to-date with current public bids and ten - ders can apply to register as a supplier with Water Corporation, and gain access to the supplier portal at https://watercorpora - tion.com.au/home/suppliers/ procurement. Desalination is a significant investment in assets ... climate change and growing communities make this likely to increase Dean Toomey, WSP Australia and New Zealand