Solid year for SA Water’s poo-fect crop topper

South Australia’s number twos have yet again proven to be number one for the state’s farming sector, with 65,000 tonnes of biosolids – a by-product of SA Water’s sewage treatment process – used as soil conditioner 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, as an easy way of improving and maintaining soil health.

Produced at SA Water’s wastewater treatment facilities around South Australia 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.

“Capturing 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,” Chris said.

“Using 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 that is perfect as a soil conditioner for use in dry land farming, and on irrigated crops such as citrus or vines.

“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, which is a feather in the cap for the hardworking team.”

According to Mr Young, the production of biosolids is among several re-use opportunities harnessed by SA Water from the wastewater treatment process, 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, but they actually play a substantial role in delivering other benefits for our customers, our business and the environment,” Chris said.

“A good example of this is our recycled water network sprawled across parts of the state, which repurposes around one in every three litres of wastewater to irrigate green open spaces like the Adelaide Park Lands and agricultural crops, as well as 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, with the capture and conversion of biogas to electricity, a major source of renewable energy powering our three largest metropolitan plants at Bolivar, Glenelg, and Christies Beach.

“We want to be seen as environmental leaders in South Australia, and 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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