Melbourne Water recently commenced its $100 million upgrade of the city’s sewer network, parts of which are more than 100 years old.
Construction on six ageing pipelines, located in Brighton, has commenced. The areas of Maribyrnong, Spotswood, Hawthorn, Pascoe Vale and Kew will follow later this year. The sewer relining program will target around 15km of sewer pipes all together.
The target sewers will be relined using trenchless technology, thanks to which there will be no need to dig up and replace existing pipes. Trenchless technology works by inserting a seamless, flexible textile liner, cut to length and soaked in resin. It is inserted into the drain using compressed air, before curing it with hot water pumped through the pipe. The inside of the pipe is then considered to be stronger than PVC pipe and has a life expectancy of around 50 years.
The target sewers will be relined using trenchless technology, thanks to which there will be no need to dig up and replace existing pipes.
Eamonn Kelly, General Manager of Program delivery for Melbourne Water, explains the challenges and benefits to the project:
“Using these trenchless methods to rehabilitate ageing or damaged sewer pipes helps to minimise the impacts on the local community as it means there’s no need to dig up the existing pipe.
“Much of Melbourne’s existing sewage system was constructed at around the same time—in the late 1890s, after the 1888 Royal Commission into Melbourne’s public health, which led to the creation of the Melbourne and Metropolitan Board of Works.”
The modern city of Melbourne has evolved since then, all built atop of the antique sewer pipes, and still connecting millions of homes to the sewer.
“As a result, many of these assets are reaching the end of their life at the same time, so we need to address a number of sewers around the city fast,” said Kelly. “The first sewer to be relined in the program is actually connected to what is believed to be Melbourne’s first flushing toilet, located in a home on the corner of Princes Street and Rouse Street in Port Melbourne.”
Back in 1907, construction of the original sewer took around two years to build, by hand and by unskilled workers.
Back in 1907, construction of the original sewer took around two years to build, by hand and by unskilled workers. However, the recent upgrades to the same pipes will be completed in approximately ten months, all things going to plan.
“Each of these sewer relining projects will improve public and environmental health by reducing the risk of sewage spills due to cracks, leaks, and bursts and ensure reliable services into the future,” says Kelly.
In addition to the relining projects, a micro tunnel boring machine (MTBM) has just completed ten weeks of excavating City West Water’s Spencer Street Sewer. It will serve to create more than 700 metres of new sewer main which will connect to the existing pipes between Lonsdale Street and Flinders Lane in the CBD. Quinn Civil has been the Principal Contractor of that project, with micro tunnelling operations subcontracted to Bothar Boring.