McGillivray Oval Irrigation Project
The Project
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The University of Western Australia (UWA) Sports Park is the site of a two-year water recycling demonstration project. The project is a joint initiative between the Water Corporation, the Water and Rivers Commission and UWA and will be a significant milestone towards relieving pressure on our water supplies.
The scheme uses up to two million litres of treated wastewater a day from the Water Corporation’s Subiaco plant for six to nine months of the year – irrigation in the winter months is not necessary.
The project is jointly funded by the Federal Government’s Coast & Clean Seas Program and the Water Corporation.
Water recycling in Western Australia first started in the late 1950s and since then over 80 schemes similar to this proposal have been undertaken throughout the State.
“ Currently the Water Corporation successfully operates 40 recycling schemes in regional WA providing lush recreational areas without compromising precious water supplies,” says Mark Herbert, Water Corporation Business Manager Wastewater. “The traditional use of groundwater for irrigation purposes may not be sustainable in the long term and alternative sources must be considered.”
“ Recent research in Perth shows that 90 per cent of residents support recycling treated wastewater for recreational areas, industrial or agricultural purposes. We are very pleased to be able to demonstrate the effectiveness of using this resource in an area as well used as the UWA Sports Park.
“ Careful management of recycled water is important to cost effectively minimise any environmental or health risks. Both the Health Department of WA and the Department of Environment are responsible for the assessment, approval and regulation of the scheme.”
The project is now operational and research results are beginning to be compiled.
What is the project?
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The project includes filtration and chlorination of secondary treated wastewater from the Subiaco wastewater treatment plant. This water is piped 800 metres in a new (300 mm diameter) pipeline under Brockway Road to the UWA Sports Park where it connects to the existing reticulation system in the Park. The map above shows the area to be reticulated.
Only the ovals are watered with recycled wastewater. Other areas around buildings, sand pits and road verges continue to be watered with bore water.
The reticulation is operating on recycled water from 9pm or 30 minutes after the completion of scheduled activities (whichever is later) and ceases at 1.00am.
On occasions when it is not possible to use recycled water to achieve desired irrigation, groundwater is used. The Health Department of WA sets the conditions for use and the hours of operation. The Sports Park is watered through a controlled access system, which means the recycled water irrigation system is not on while the sports fields are being used.
The health standards applied to the recycled water quality are a chlorine residual of >1 part per million and thermotolerant coliforms <1000 cfu (colony forming units) per 100 millilitres.(A farm dam would typically have 100-1000 cfu/100 millilitres.)
The recycled water is constantly monitored for chlorine levels by the Water Corporation using a Supervisory Control and Data Acquisition (SCADA) system. If these chlorine standards are not met, the system automatically turns off and irrigation continues with bore water. UWA is responsible for the daily operation, coliform sampling and maintenance of the system at the Sports Park.
What are the benefits of this project?
Recycled water contains some nitrogen and phosphorus in solution. Use of recycled water significantly reduces the amount of fertiliser that is applied to recreation areas. This is a cost saving for UWA. The project will be using a resource that is currently returned to the environment through ocean disposal.
The success of this project will open up new possibilities to reduce pressure on water supplies throughout Perth. Other parks, golf courses or recreational areas may benefit from recycled water – many groups have already shown interest in using recycled water for irrigation purposes.