More desalination and reuse potential in Western Australia
Western Australia's Water Corporation is considering up to three seawater reverse-osmosis desalination plants along the southern coast of its area, known as Lower Great Southern, as part of a potential portfolio of water resources for the next 30 years.The plants are included as options in the corporation's document Water Forever: Lower Great Southern: Final Report published at the end of 2010. Use of reused wastewater, conservation including rainwater-tank incentives, surface water and groundwater are also among the options.
The municipalities that will be in need of supplies are Walpole, Denmark and Albany, and potential sites for desalination have been identified in each area. In Albany, the document envisages a staged development, each stage supplying about 4 million m³/year.
The corporation ran a "community engagement" programme in 2009 and concluded that community support was strong in the areas of :
Water reuse is already under way or planned in these areas.
Water Corporation aims to recycle 100% of treated wastewater from Albany's wastewater treatment plant (WWTP). This is used to irrigate 575 ha of Tasmanian blue gum trees, but the corporation is looking for higher value uses for the recycled water. One option which is currently being investigated is for the water to be recycled in Grange Resources' proposed Southdown Magnetite Project.
At Walpole, Water Corporation is proceeding with upgrades to increase the capacity of the existing WWTP. It is also developing a new tree farm to enable 100% reuse of recycled water through irrigation.
Detailed design is under way in Denmark for an Aus$ 8 million (US$ 8.1 million) more energy-efficient WWTP, and the corporation expects it to be in full operation by 2012. Planning for Denmark also considered the future potential for recycled water to be used at a number of sites.
Mount Barker is another Lower Great Southern town where an innovative approach to reusing treated wastewater has resulted in nearly 100% recycling. After treatment at the Mount Barker Wastewater Treatment Plant, the water is chlorinated then pumped to a storage dam at a nearby vineyard and irrigated onto the vines over summer.
The nitrogen-rich water has allowed the vineyard to reduce its application of artificial fertiliser, providing economic and environmental benefits. This scheme has now been operating for 10 years, and during this time the vineyard has continued to produce some of the fine wines for which the Great Southern has become famous.