Unitywater has renewed more than 53 kilometres of wastewater pipelines and 317 maintenance holes across Moreton Bay, the Sunshine Coast and Noosa, in a major infrastructure push to improve reliability and reduce odour. The $400 million program, part of the utility’s five-year replacement and renewal plan, is helping to strengthen the region’s wastewater network while minimising impacts to residents.
Executive Manager of Sustainable Infrastructure Solutions, Mike Basterfield, said the initiative was delivering strong operational and environmental results by extending the life of existing infrastructure.
“Wastewater mains on average are about two metres deep and some are as deep as four metres below ground, so to be able to line the inside of existing pipes and not excavate and replace the entire pipe is much more cost-effective and less disruptive to the community,” Basterfield said.
The wastewater pipe relining process uses two advanced methods (spiral relining with PVC plastic and a ‘cured-in-place’ polymer UV liner) to create a sealed, durable interior surface without the need for excavation. This innovation not only cuts costs but also reduces carbon emissions and traffic disruptions during works.
Basterfield said the relining program also helps mitigate the corrosive effects of hydrogen sulphide, a naturally occurring gas in wastewater that can degrade infrastructure over time.
“Our Network Programs team has a comprehensive, proactive approach to identify which of our assets need to be renewed, including cleaning programs, CCTV inspections, jet blasting to remove debris and roots, and condition assessments,” he said.
In the Sunshine Coast and Noosa regions, 25 kilometres of pipe, roughly the distance from Peregian Beach to Maroochydore, have been relined. In comparison, 26 kilometres have been renewed in Moreton Bay, equivalent to the distance between Morayfield and Redcliffe.
The wastewater pipe relining program also involves upgrading maintenance holes to reduce stormwater infiltration during periods of heavy rainfall.
“Stormwater and wastewater are two separate systems that shouldn’t mix, and when large volumes of stormwater enter the wastewater network, it becomes inundated,” Basterfield said. “If we didn’t carry out these important works, overflows could occur inside private properties and in the environment”.
Unitywater’s investment forms part of a broader $2 billion commitment over the next five years to deliver critical water and wastewater infrastructure supporting more than 800,000 residents across South East Queensland.