In an Australian first, a Queensland wastewater treatment plant will use gasification to drastically reduce the volume of sludge for disposal.
Logan City Council (LCC) is embarking on the project at its Loganholme Wastewater Treatment Plant, which services 300,000 people and produces 34,000 tonnes of biosolids each year.
Currently, six truckloads of biosolids are driven 300 km to the Darling Downs each day, where the loads are used for land application. This costs $1.8 million – or 30% of the treatment plant’s operating costs – per year.
LCC said the new gasification facility would help reduce the volume and cost of biosolids waste disposal by about 90%.
Gasification works by creating fuel from biosolids that have been dewatered, dried and treated at high temperatures.
This produces a biochar containing carbon, phosphorus and potassium that can be used as an environmentally-friendly soil treatment.
The facility will capture heat from the biosolids treatment process, which will be used for sludge drying, and will be supported by an onsite solar power system.
LCC Acting Road and Water Infrastructure Director Daryl Ross said the project was about finding more sustainable management solutions that also reduced the environmental impact of disposing of sludge.
“Costs are increasing due to rising electricity prices, increasing population and tightening of government regulations on carbon reduction and managing persistent organic pollutants in soils,” Ross said.
The $17.28 million project includes $6.2 million in funding from the Australian Renewable Energy Agency (ARENA).
ARENA CEO Darren Miller said it was an important project that would lead the way for other councils.
“Logan City Council’s demonstration project is expected to deliver a commercial business case for the gasification of biosolids for similarly sized wastewater treatment plants across Australia,” Miller said.
“The key knowledge learned from this installation will be significant given the first-of-kind deployment.”
An initial proof-of-concept trial is scheduled to start in February next year, with construction set to begin in July 2020. The facility is expected to become fully operational by July 2021.