UQ sewer technology bound for overseas

Researchers from The University of Queensland’s (UQ) Advanced Water Management Centre have developed technology which uses free nitrous acid to remove biofilms that adhere to the inner surfaces of sewer mains, thus controlling odour and corrosion.

Now, UQ commercialisation company UniQuest has negotiated an exclusive licence agreement with USP Technologies, a US provider of chemical treatment programs for water and wastewater applications.

“Corrosion and odour problems in sewers are most often caused by sulfate-reducing bacteria in sewer biofilms that produce hydrogen sulfide,” explained lead researcher and Advanced Water Management Centre Director Professor Zhiguo Yuan.

“Hydrogen sulfide is released into the atmosphere above the wastewater, causing odour problems, and is converted by sulfide-oxidising bacteria into sulfuric acid, which is corrosive to concrete sewer pipes.

“Sewer networks can include many kilometres of sewer pipe and various topographical elements, such as rising mains.

“These can create ‘hot spots’ where sulfate becomes sulfide, accelerating corrosion and causing odours, leading to community complaints.

“Most existing treatments for managing sulfide-related problems in sewers involve sewer pipe lining, sewer air ventilation with follow-on air treatment and round-the-clock chemical dosing, resulting in high operating costs.”

USP General Manager Tom Walkosak said the “innovative and cost-effective” UQ technology is different from existing treatments because it is “delivered intermittently, provides longer duration control and effectively stops the production of hydrogen sulfide at its source”.

“It is highly effective, can be used in sensitive environmental areas or to treat smaller lines, and offers water utilities the opportunity to make significant reductions to their maintenance costs.”

The first Australian field trial of the UQ technology was undertaken by UQ in 2012 in collaboration with USP and the Gold Coast City Council in 2012, followed by a second field trial in partnership with USP and Unitywater at Scarborough on Moreton Bay in 2014. As explained by UniQuest Chief Executive Dr Dean Moss, “These trials led to further refinement of the technology and ongoing field tests in the US.

“It’s always exciting to see tangible results from industry engagement, but this is a fantastic example of universities and companies working together to produce a solution to a costly problem and then to refine that solution,” Dr Moss said.

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