Magnets put to work to clean up ‘forever chemicals’

Brisbane scientists are developing technology that could be a key to removing toxic “forever chemicals” from the environment.

The system developed at the University of Queensland uses magnetic resins to remove PFAS from sewage, which can then be used as fertiliser or compost without contaminating land or water supplies.

“PFAS is present everywhere – in the water we drink, the air we breathe and the soil we plant,” said Dr Cheng Zhang, who developed the technology.

“They’re highly persistent, they travel everywhere … that’s why we should care about the issue now.”

PFAS chemicals have been mass-produced since the late 1940s and are prized for their water-resistant and heatproof properties.

They do not break down in nature, and some variants are known to cause serious health conditions, including cancer and high cholesterol.

Last year this masthead revealed secret testing by south-east Queensland water authority Seqwater found high levels of the carcinogenic PFAS variant PFOA – used to make non-stick pans and other consumer goods – at Brisbane drinking water treatment plants.

One university expert described the readings at Mount Crosby as the highest he had seen in Australia. At 36 parts per trillion, it was seven times the level considered safe by the US Environmental Protection Agency, but within the range considered acceptable in Australia.

Other testing has uncovered forever chemicals in drinking water in towns across Queensland, New South Wales, Victoria, Western Australia, the Northern Territory, Norfolk Island, and in Canberra’s catchments.

The technology developed at UQ begins by mixing a magnetic resin sorbent into sewage to absorb PFAS material. Magnets are then used to pull it back out.

The resin technology has previously been used to remove PFAS from water, but this is the first time it is being trialled on sewage.

“Contamination is significant [in sewage],” Zhang said.

“In a lab at the University of Queensland, we tested how it performs within the biosolids, and we actually achieved more than 99.9 per cent efficiency.

“The big challenge in removing PFAS is it uses a high-energy input to burn it, or something else, but not with [our system].”

Zhang and a group of commercial partners are planning to trial and roll out the program at treatment plants over the next three years.

About 15 people are on the development team, which has been working on PFAS contamination solutions for about a decade.

The technology has been patented by the University of Queensland’s commercialisation arm, UniQuest.

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