Water recycling: Waste not, want not

In this edition of What Works, software powers smarter water management in drought-stricken southeast Australia.

By Christine LaFave Grace, managing editor

Googong Township, a planned community about 10 miles southeast of Australia’s national capital of Canberra, aims to offer a “life like the one you enjoyed growing up, but with all the bells and whistles that go with modern living.” Probably not part of the warm nostalgia the township seeks to inspire: living with the effects of a 10-year drought. 

But that’s the reality for Googong, whose first residents moved in to the community in March 2014, and especially for its planners. When it became clear to Googong Township Proprietary Limited, the township’s development partnership, that even severe water restrictions wouldn’t be enough to ensure sufficient water availability for the community’s planned 18,000 residents, planners moved to add a water recycling plant to the development.

GTPL sought a plant design that would incorporate a membrane bioreactor (MBR) wastewater treatment process to combine membrane filtration with biological wastewater treatment so that filtered and disinfected water can be reused for residential irrigation, toilet flushing, and household washing.

The ultimate goal was to be able to meet water demand for Googong’s target population of 18,000 residents using only the equivalent amount of water as is typically required for 6,500 people.

GTPL needed to optimize use of water on the 780 hectares of land it intends to develop, says Terry Sowden, principal CAD designer and piping specialist at MWH Global (now part of Stantec), which designed Googong’s water recycling plant. “The membrane biological reactor provides a compact solution that achieves this,” he said via email.

According to the township’s website, Googong residents should receive their first recycled water from the new plant to their homes in mid-2018; the exact timeline is determined by the local council. The entire water distribution and recycling process looks like this: Fresh potable water is drawn from the main supply line to Canberra and stored in potable water storage reservoirs in Googong. From there, it’s gravity-fed into homes, schools, and businesses. The wastewater that’s collected gets pumped to the recycling plant for treatment, after which it is sent to separate recycled-water storage reservoirs, to be gravity-fed back to homes for nonpotable uses.

Sounds simple enough, relatively speaking. But complicating the plant’s design for Stantec, which has extensive experience with large-scale water-engineering projects on five continents, were tight deadlines and tough terrain.

GTPL “had purchased the land and was funding the project so was keen to start selling properties to recoup their losses,” Sowden noted
The other major hurdle, Sowden said, was the site itself, which was “severely restricted and also located on steeply sloping terrain overlaying rock formation.”

Given the challenging parameters of the project, easy collaboration among Stantec engineering experts across Australia and in Pune, India, and the ability to provide proof of concept were going to be crucial for the design team. The solution: customized engineering collaboration software and 3D modeling tools, both from Bentley Systems.

Given the terrain’s complexity, it was especially imperative that the plant’s final design not require rework, and that meant getting input early on from assorted stakeholders in the plant. As design teams worked, 3D modeling presented an invaluable visualization of the proposed plant that allowed stakeholders to point out design, construction, operations, and maintenance issues before the first excavator rolled on to the site.

Now, with the development’s preeminent water worries addressed, Googong can get on with advancing its plan to be a place where “your neighbours are neighbourly and your children are practically free-range” – and fresh water consumption is 60% less than it otherwise might be.

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