South Australia’s number twos have yet again proven to be number one for the state’s farming sector. 65,000 tonnes of biosolids were used as soil conditioners in the production of crops during the past year.
Statistics for 2022-23 show the whopping tonnage was spread over approximately 13,000 hectares of broadacre cropping land. This is an easy way of improving and maintaining soil health.
The biosolids are produced at SA Water’s wastewater treatment facilities around South Australia. It needs to be made in accordance with strict guidelines and regulatory requirements under the Environmental Protection Act (1993). The high-quality, organic biosolid material is distributed free of charge to farmers each year from the utility’s Bolivar Wastewater Treatment Plant.
SA Water’s General Manager of Operations, Chris Young, said this is a great example of a sustainable circular economy in action.
“We capture the wastewater produced by toilets, kitchen sinks and laundries across the state. Our sewer treatment process separates the liquid and solid waste, known as sludge,” Young said. “SA Water uses a process called anaerobic digestion. Any organic matter present in the sludge is then broken down before being dried out in on-site fit-for-purpose lagoons.”
“The end result is an organic, fertiliser-like product. It is perfect as a soil conditioner for use in dryland farming, and on irrigated crops such as citrus or vines,” he added. “Despite a cooler-than-usual spring and summer underpinning a dip this past year on the 2021-22 record production of 90,000 tonnes, it’s still a great outcome to achieve an above-average volume of biosolids distributed to more than 80 farmers. The feedback from farmers has indicated an extremely high level of biosolid quality as well as customer service from our people on the ground. This is a feather in the cap for the hardworking team.”
Biosolids program supports the agriculture industry
The production of biosolids is among several re-use opportunities harnessed by SA Water from the wastewater treatment process. It is designed to benefit the environment and its operations.
“Many people might think our wastewater treatment plants just do the basic job of treating our customer’s pee and poo. However, they actually play a substantial role in delivering other benefits for our customers, our business and the environment,” Young said. “At SA Water, we provide our state’s most important and essential service – the delivery of safe, clean water and dependable sewerage services.”
SA Water is a corporation owned by the people of South Australia. It is committed to providing its 1.7 million customers with trusted water services that represent excellent value. SA Water invests around $300 million a year in sustaining and enhancing our state-wide network. It also works to ensure it continues to play an integral role in South Australia’s social and economic development.
A good example of this is SA Water’s recycled water network sprawled across parts of the state. SA Water repurposes around one in every three litres of wastewater to irrigate green open spaces. It is also a sustainable and climate-independent water source for dual-reticulated housing developments such as Bowden.
“The wastewater treatment process also plays a unique and innovative role in reducing our electricity costs. The capture and conversion of biogas to electricity is a major source of renewable energy powering our three largest metropolitan plants at Bolivar, Glenelg, and Christies Beach,” said Young. “We want to be seen as environmental leaders in South Australia. We look forward to continually growing and expanding our sustainability practices as we strive towards zero net carbon emissions.”
Operated in conjunction with service delivery partner SUEZ, SA Water’s metropolitan wastewater treatment plants at Bolivar, Glenelg, Christies Beach and Aldinga process an average of 300 megalitres of sewage every day.
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