Melbourne, Australia – Fatbergs are a significant cause of blocked drains and sewers. Now, engineers at RMIT University in Melbourne have come up with a potential solution – a polyurethane-based coating to prevent the solidified fat from adhering to the concrete pipes.
Sewer-blocking fatbergs form from a mixture of fat, oil and grease (FOG) discharged into the wastewater system, with the assistance of calcium released from concrete sewers. The RMIT team have developed a PU coating based on a zinc(II)–dimethylglyoxime–urethane-complex that can reduce the amount of calcium released from concrete by up to 80% compared with uncoated concrete.
In the study, the team simulated a sewer environment under extreme conditions designed to significantly speed up the fatberg formation process over 30 days. They found the coating reduced the FOG build-up by 30% on treated versus untreated concrete.
“The reduction of fat, oil and grease build-up can be attributed to the significantly reduced release of calcium from coated concrete, as well as less sticking of FOG on the coating surface compared to the rough, uncoated concrete surface,” said Biplob Pramanik, who led the study.
He added that while traditional concrete coatings such as magnesium hydroxide are effective in controlling sewer corrosion, they can inadvertently contribute to FOG build-up by interacting with fatty acids.
The new coating is stable in water, and can withstand temperatures of up to 850°C. Importantly, it is self-healing at room temperature, extending its lifespan.
They are now working on an improved coating that would give a greater reduction of FOG deposition in sewers by enhancing its self-healing capabilities and mechanical strength.
The work has been published in the Chemical Engineering Journal.
