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Legislative Council - Fifty-Second Parliament, First Session (52-1)
2011-09-14 Daily Xml
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WATER PROJECTS

The Hon. J.S.L. DAWKINS (15:42): Earlier this month, the Leader of the Opposition, Isobel Redmond, and I visited two innovative water projects in the City of Tea Tree Gully. Accompanied by Mayor Miriam Smith, council CEO Di Rogowski, Director of Assets and Environment Thornton Harfield, and Manager of Environment Sustainability Brenton Curtis, we first visited the water treatment plant at Wynn Vale dam.

Situated on Park Lake Drive, this plant captures and polishes stormwater for aquifer storage and recovery. This Waterproofing Northern Adelaide project has seen a number of wetlands, aquifer storage recovery schemes, and a distribution main being installed across the city to capture and harvest as much stormwater as possible.

Installation of this treatment facility adds to the project by using ultraviolet technology and pressure filtration to further cleanse the stormwater and essentially polish it, acting as a mini water treatment plant. Council's senior water engineer David Baldwin explained the concept as follows:

The city of Tea Tree Gully is a reasonably built up urban environment and for water re-use to be sustainable, we need to look at new and innovative ways of capturing stormwater, cleaning it and storing it for later use. Council staff tested several different water filtration systems at the site and this particular treatment facility is a great option for our city. It is compact in size and cleanses the captured stormwater more thoroughly than even our wetlands do.

The treatment device works by pumping stormwater run-off through a number of filtration units consisting of a sand type substance that rids the water of unwanted pollutants such as sediments, heavy metals and organic material. The water is then disinfected through ultraviolet technology and later stored underground in aquifers until needed to water the city's reserves and parks.

Secondly, we visited the council's water re-use facility at Greenwith Road, Golden Grove. Following the successful introduction of the stormwater harvesting project, the City of Tea Tree Gully has developed a water re-use facility which complements the water re-use work it is already doing and involves the treatment of wastewater for non-drinking uses, such as irrigation. Wastewater is sourced from the SA Water network and includes water from the city's community wastewater management system.

The treatment facility delivers up to 1.1 million litres per day, with a possible expansion to 1.6 million litres per day. This will make sure a reliable water source is available to irrigate parks, sports fields and gardens, while reducing demand on mains water. The treatment process incorporates the latest technology to deliver the most cost-effective and environmentally-friendly recycled water that meets stringent health standards.

The wastewater undergoes a primary treatment of screening and grit removal to remove suspended matter before it is discharged into the secondary treatment, which consists of an activated sludge process. The wastewater is aerated in tanks, where bacteria and other microorganisms feed on the wastewater. This biological process reduces contaminants and increases bacterial cells or biomass. The biomass is recycled through the system, and excess biomass is settled as sludge and disposed to the SA Water sewerage network. This 'class B' water then passes through the tertiary treatment process to remove fine particles, including bacteria and most viruses, followed by final disinfection.

The main environmental and aesthetic advantages are: less effluent discharged into Gulf St Vincent; reduced reliance on mains water and groundwater for irrigation of parks and gardens; less impact on those parks and gardens during times of water restrictions; reduced costs for irrigation water; and less reliance on the River Murray and Adelaide Hills catchments.

I give great credit to the City of Tea Tree Gully for its commitment to these innovations, both in a policy and a financial sense, and I thank the council for taking the time to demonstrate these initiatives in action. I should add that both the projects have been developed with the support and assistance of the Australian government and the Adelaide and Mount Lofty Ranges NRM Board.

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