Water Infrastructure Group has been awarded a contract with Sydney Water to rehabilitate the Narrabeen Submain in Sydney’s Northern Beaches.
The $9.3 million project will improve the structural condition and operating performance of the wastewater system and improve access for future maintenance work.
The Narrabeen Submain starts in Collaroy and travels through Brookvale before joining the Northern Suburbs Ocean Outfall System, which flows to North Head Wastewater Treatment Plant.
The project involves repairing:
• 3937m of sewer pipe with diameters ranging from 1200–1800mm;
• 330m of concrete-lined rock tunnel;
• 404m of rock tunnel; and
• 34 maintenance holes.
Stijn Sampermans, Water Infrastructure Group’s Senior Project Development Engineer, said the work on the submain would commence in August 2013.
“We’ve developed a very efficient and safe access methodology for this type of work on projects such as our recent rehabilitation of four deep manholes on the Northern Suburbs Ocean Outfall System. Our crews are fully trained and certified for working in confined space environments and have a lot of experience working in large trunk sewers and dealing with live flow conditions.
“Our proprietary Panel Lok system is the main technology we are using for the relining of this critical sewer. It is a proven product and we have developed an excellent work methodology and strong track record for rehabilitating sewers. We will stabilise the tunnel sections with rock bolting where required and protect them from further acid attack by applying Calcium Aluminate Cement to the tunnel surfaces and maintenance holes,” Stijn explained.
Work on the Narrabeen Submain is expected to be completed by mid-2014.