By Paul Hemsley

City of Sydney Lord Mayor Clover Moore has moved to reduce the amount of drinking-quality water used by residents and workers in favour of using recycled stormwater for toilets and laundries in the council’s ambitious $8 billion Green Square redevelopment.

It is the City of Sydney’s latest dive to create an environmentally friendly city by propping up its $8 billion Green Square project as the centrepiece of its wider sustainability plan by creating a water-saving plan funded by the City and the federal government’s National Urban Water and Desalination Plan, part of the Water for the Future initiative.

The City identified the water use of apartment dwellers as a problem claiming they are the highest consumers of drinking water but one third of what they use is either flushed down the toilet of used in the laundry.

The fact that this water has come from Sydney’s dams has created the need to ease the pressure because of their vulnerability to Australia’s long stints of drought, which has historically resulted in the state government laying curfews on water use when the dams were filled at dangerously low levels.

So the City has partnered with private water utility Green Square Water, wholly owned by Flow Systems Pty Ltd to design, build and maintain a recycled water network using stormwater harvested from the City’s drains.

This new stormwater harvesting infrastructure will service 7,000 residents and 8,500 workers in the new Green Square neighbourhood through 20 sites using a “parallel plumbing system” installed in Green Square’s new buildings, providing up to 900 kilolitres of recycled water every day.

The City of Sydney illustrated this amount by likening it to just under half the amount of water that can fill an Olympic-sized swimming pool.

Although the City of Sydney didn’t specify how much stormwater the new system will yield, Ms Moore said over 20 billion litres of stormwater flows out to sea from the city annually – an amount Sydneysiders are expected to consume in total by 2030

And Green Square has rarely had a shortage of water dampening the land, which has created a “ponding” problem rendering the area as a swampland in Sydney’s vicinity.

This led to the City announcing in July 2013 that it would install an underground culvert drain pipe network designed to divert water away from property and infrastructure that are at risk of water damage.

But Ms Moore said the City is already working hard to reduce mains water demand, increase recycled water use and improve stormwater quality.

“We are already bringing storm and rainwater harvesting and reuse programs to many of our parks and public buildings,” Ms Moore said.

According to the City of Sydney, the recycled water will also be used to irrigate Matron Ruby Park on the old grounds of South Sydney Hospital and the planned library at Green Square.

Flow Systems has also attempted to remove the “ick” factor surrounding recycled water by explaining its water cleansing process, which includes “ultrafiltration, reverse osmosis and purification”.

Flow Systems managing director Terry Leckie said that the water is purified to the “highest Australian standards” with the Independent Regulatory and Pricing Tribunal and NSW Health monitoring the network to ensure it meets health and safety requirements.

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