Australian engineers have invented an anti-fatberg coating for sewer pipes that could prevent the congealed masses from blocking the wastewater system and leading to overflows and flooding.
Fatbergs – solidified masses of fat, oil and grease that accumulate in sewer pipes, collecting wet wipes and other material – are a major concern for wastewater authorities globally, responsible for 40% of blockages in Australia, and a likely source for the mysterious balls that recently washed up on Sydney beaches.
To prevent fatbergs from forming, RMIT engineers developed a zinc and polyurethane coating that could be applied to concrete pipes in problem areas, publishing their results in Chemical Engineering Journal.
Dr Biplob Pramanik, the director of the water research centre at RMIT and co-author of the study, said when fat, oil and grease – washed down household sinks, or incorrectly disposed of by food service establishments – reacts with calcium from concrete pipes it forms a solid mass commonly known as a “fatberg”. Most of Australia’s major sewer pipes are concrete, he noted.
The phenomenon was “a major concern for water utilities, because they can block the sewerage system”, he said. “Around 50 to 70% of these fatbergs are linked with fat, oil and grease.”
Water authorities often use physical processes to remove the blockages, costing them “multimillions of dollars every year”.
The anti-fatberg protection could be applied to new and existing wastewater infrastructure at strategic locations such as T-intersections or maintenance holes, where slow or stagnant flow enabled fatbergs to form, Pramanik said.
But it could be several years before the product is used commercially. Pramanik described the study as a proof-of-concept of the coating material, and said the team would continue to refine and analyse the product before it could be implemented as a wastewater infrastructure solution.
According to the study, the protective coating limited the release of calcium by up to 80% compared to uncoated concrete, and reduced the formation of fatty deposits.
Greg Ryan, from the Water Services Association of Australia, said sometimes fatbergs in wastewater pipes became so hard they had to be drilled out.
“These things go down, they tend to stick to the walls of the pipe, and then as they stick, the other stuff accumulates, so you’ve got potentially wet wipes and other things that have been flushed down,” Ryan said.
He agreed preventing the masses initially forming could address the problem – as well as encouraging people to properly dispose of fats, oils and grease.
Pramanik said his research team’s experiments had shown the protective zinc-enhanced polyurethane coating was high strength, stable in very high temperatures (up to 850C), and had strong binding and “self-healing” properties that enable the material to repair itself from scratches. It also had the “dual function” of preventing corrosion, he said.
