Wastewater treatment in Australia produces three million tonnes of sludge that must then be treated and disposed of. The process is responsible for 50% of the total operating costs of wastewater treatment plants.
A researcher at the University of Technology Sydney has developed a new treatment technology that would not only reduce the amount of waste by a third, but also recover energy from the sludge itself.
The end product would also be biosolids that are safer for fertilizer than are currently being produced.
Relying solely on a waste byproduct of the sewage treatment itself, this technology was invented by Huan Liu, who is completing his Ph.D. in college. His research work has been published in Nature and praised by the Australian water industry.
“It’s a closed-loop technology: the only chemical needed is a waste byproduct of sewage treatment,” says Huan.
“Instead of being a pollutant to wastewater treatment plants, the waste byproduct becomes a useful part of the process,” he says.
The process is also much more efficient at removing pathogens from the final product. Huan showed an 82% reduction in pathogens and a 20-70% reduction in antibiotic resistance genes with traditional procedures. Residual waste could reach Grade A biosolids according to the NSW Environmental Protection Agency, reducing the health risks of using the sludge as fertilizer.
Huan estimates that if the technology were applied to wastewater treatment plants in New South Wales alone, it would save taxpayers approximately $5 million a year.
The technique works in all wastewater treatment plants with anaerobic digestion and only requires the installation of a small and simple mixing tank. The technology is being commercialized.
The estimated payback time would be less than a year, while the benefits for plants and society will be long-lasting.
Ecological fertilizer from wastewater nutrients
Provided by Freshscience
Citation: Closed Loop Technology Improves Sludge Energy Recovery and Reduces Sludge Disposal Costs (September 1, 2022) Retrieved September 1, 2022 from https://techxplore.com/news/2022-09 -closed-loop-technology-energy-recovery-lodo.html
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