Record tonnages of treated poo off to SA farms

A massive 90,000 tonnes of biosolids - created as a by-product from treated wastewater - is forecast to be collected for use as fertiliser from SA Water’s wastewater treatment facilities this financial year, as demand from the state’s farming sector continues to grow.

This would make it SA Water’s highest volume of biosolids disposal heading off for re-use this millennium, and well eclipses the 55,000 tonnes collected on average each year in South Australia.

Safely distributed from SA Water’s Bolivar Wastewater Treatment Plant, organic, high-quality biosolid matter is produced every year to help primary producers improve soil quality for dry land crops like cereals, or irrigated permanent crops such as citrus or vines.

SA Water’s Senior Manager Production and Treatment Lisa Hannant said the record tonnage is a great outcome for the state’s farmers.

“As proactive environmental leaders in South Australia, we’re always looking at how we can reduce waste and increase the re-use of by-products from our wastewater processes, to benefit the community,” Lisa said.

“Biosolids are an increasingly popular method of improving soil quality by the state’s primary producers, and by tapping into our accrued stocks of biosolids we’ve been able to significantly grow in our ability to meet this increasing demand.

“We have also been able to increase the amount of biosolids available for farmers by collecting more supply from our regional treatment plants located in Port Pirie, Port Augusta, Murray Bridge and the Adelaide Hills.

“To put the predicted biosolid demand into context, the last time our Bolivar facility provided more than 80,000 tonnes of biosolids was way back in 2007-08, setting the existing record for biosolid production of 86,030 tonnes.

“While the wetter than anticipated summer has presented its challenges, we’re still on track to achieve our bumper season and provide a great outcome for our customers and the environment.

“The feedback from farmers on the quality and service received this year is terrific, and it’s great to see recognition for the work of our team on the ground who are providing a high-quality and safe end product.”

Produced in accordance with strict guidelines and regulatory requirements under the Environmental Protection Act (1993), the treatment of wastewater sludge into reusable biosolids involves gravity thickening and dissolved air floatation thickeners, before anaerobic digestion is used to speed up the breakdown of organic matter.

Following a rigorous treatment and storage process, the resulting safe, high-quality biosolids are made available for primary producers to collect free of charge at SA Water’s Bolivar Wastewater Treatment Plant.

“The production of biosolids is just one of the positive reuse benefits delivered through the wastewater treatment process, with one in every three litres of wastewater going on to be reused as recycled water in public parks and to supply dual-reticulation systems in housing developments across metropolitan Adelaide,” Lisa said.

“We’ve also been able to harness the renewal energy created through the biogas generated in the breakdown of bacteria in the treatment process, with the estimated 15 gigawatts per hour of electricity created each year enough to meet around 80 per cent of the electricity needs of our three major wastewater treatment plants in metropolitan Adelaide.”

Operated together with metropolitan production and treatment alliance partner SUEZ, SA Water’s three largest wastewater treatment plants at Bolivar, Glenelg, and Christies Beach process more than 250 megalitres of sewage every day.

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