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GHD-led consortium to develop Sydney plan for city-wide recycled water network

A consortium has been selected by the City of Sydney to develop a decentralised water master plan for the Local Government Area which would include Australia’s first city-wide recycled water network and significantly reduce demands on drinking water supplies.

The consortium, selected after a competitive tender process, comprises engineering consultants GHD, the Institute of Sustainable Futures at the University of Technology, Sydney and Public Private Partnership Consultants P3iC.

It will develop different business models to implement the decentralised water plan including a private sector water services company or a public/private joint venture.

The City of Sydney Local Government Area currently imports 32 gigalitres of drinking-quality water each year, the equivalent of 12,800 Olympic pools, mainly from Warragamba Dam. An estimated 80 per cent could be supplemented by recycled water including toilet flushing, laundry, air conditioning cooling towers and irrigation.

The recycled water network would connect to apartment, commercial and institutional buildings which are responsible for 80 per cent of the water consumption in the LGA. In an Australian first it would allow buildings to take recycled water from the network and to supply any excess recycled water to the network.

"Despite the unusually wet year we have just had, in the longer term our drinking water supplies will come under increasing pressure from a growing population and climate change with hotter and dryer weather predicted over the coming decades," said Lord Mayor Clover Moore MP.

"The recycled water network is part of a long term strategy to make better use of our water resources and will provide a model for other Australian cities".

The water master plan would also outline water efficiency measures to reduce consumption and methods to collect more water locally, such as stormwater harvesting.

The sources of recycled water could include; treated stormwater, treated water from kitchens and laundries, known as grey water, and cleansed and disinfected black water sourced from sewers.

Grey and or black water recycling systems are already in use at Sydney Olympic Park, the Workplace 6 building in Ultimo, Pennant Hills Golf Club and Kogarah Council. They are also planned for use at the new city office tower under construction at 1 Bligh Street and the proposed new Global Switch data centre in Ultimo.

The City is currently working on the first stage of an $8 Million joint Federal project at Sydney Park and Green Square to capture and cleanse 740 million litres of stormwater per year, the equivalent of about 300 Olympic size swimming pools, from surrounding streets. This water would be used in parks and gardens and fed into the recycled water network.

The plan will also identify projects and programs that will help the City achieve its target of 50 per cent reduction in pollutants entering waterways and to control the release of stored stormwater during heavy rain to limit flooding as a climate change adaptation measure. These projects will include stormwater harvesting and integrating natural treatment devices such as raingardens into the City’s roads and footpaths.

Allan Jones, Chief Development Officer, Energy and Climate Change said ‘The type of city-wide recycled water network has not been implemented anywhere else in Australia. Therefore, the plan will also look at the business models to implement the network and any regulatory barriers that may prevent or limit the implementation of this very much needed climate change adaptation measure.’

The City Council accounts for 1.5 per cent of water use in the local government area. Its consumption has fallen by 37 per cent over the past six years to 432 mega litres in 2008-2009.

It has implemented a number of water saving initiatives including retrofitting council buildings, parks and pools with water efficient dual flush toilets, and tap aerators, installing rainwater tanks at nearly 20 childcare, kindergartens and community centres and completing 20 stormwater harvesting and water reuse projects to irrigate the City’s park and sporting fields.

The recycled water networks identified in the Plan will be integrated with the city’s planned low carbon zones powered by trigeneration plants, with common trenches used to house pipes for recycled water, district heating, cooling and automated waste collection. The zero carbon waste heat from trigeneration plants could also be used for water treatment by the local recycled water treatment stations.

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