A record-breaking 90,000 tonnes of biosolids are forecast to be collected in South Australia this financial year according to SA Water. If this amount is collected it will neatly surmount the yearly average of biosolids and will provide farmers with a free boost of soil nutrition.
Biosolids are created as a by-product wastewater treatment and are effectively human faeces that have been bacterially processed into a useful slurry. The ones collected by SA Water will be used to improve the soil quality for dry land crops like cereals or irrigated permanent crops such as citrus or vines. Producers and farmers are able to pick them up free of charge from the Bolivar Wastewater Treatment Plant.
“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,” said SA Water’s Senior Manager Production and Treatment Lisa Hannant.
“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.”
The biosolids are produced according to strict guidelines and regulatory requirements, with wastewater being run through a series of processes to convert it into a useful product. The previous record of over 86,000 tonnes of biosolid was set in the 2007–08 financial year and the average amount in a year is about 55,000 tonnes.
“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,” Hannant said.
The biogas generated in the processing of wastewater is able to be used too, with about 15 gigawatts per hour being created per year, which was able to meet about 80% of the electricity needs of Adelaide’s wastewater treatment plants.