Melbourne Water is currently undertaking works to rehabilitate a 114-year-old sewer in the inner-Melbourne suburb of Carlton.
The Carlton main sewer transfers sewage from the suburbs of Carlton, Brunswick and the southern areas of Coburg to the Western Treatment Plant at Werribee, Victoria.
It was originally built in 1900 by Melbourne Water’s predecessor, the Melbourne and Metropolitan Board of Works (MMBW), which was established in 1891 to take responsibility for the city’s water supply and sewage treatment. The original brick-lined tunnel is now suffering the impacts of its age and is unlikely to cope with future demand.
To prevent possible collapse or blockages, Melbourne Water is relining a 1.35km section of the sewer between Pigdon and Princes streets in Carlton North. The project will be undertaken by a KBR and John Holland joint venture.
The relining works will use existing manholes in the area, and require the construction of one new shaft. A balloon-like liner will then be inserted into the sewer tunnel and filled with warm water, causing the liner to adhere to the brick sewer walls. Once it has stuck, the water will be drained, leaving only the liner.
A new 510m sewer bypass connection will also be constructed to compensate for the reduced diameter of the relined main sewer and accommodate population growth in the area. The sewer bypass will be 1.4m in diameter and run along Pigdon and Scotchmer Streets, between Amess Street in Carlton North and Rae Street in Fitzroy North.
This new section of sewer will be tunnelled under the street up to 10m below ground and connect the Carlton main sewer with another Melbourne Water sewer.
This will require two shafts to be constructed, one of which will serve as the launching site for the tunnel boring machine. The machine will then bore underground in a westerly direction to the second shaft site.
This vital project will help future-proof the Melbourne area’s sewerage network, hopefully allowing it to deal with the demands of a growing population for another century or
more.
