How Our Sewerage System Works Today - the Sewage Journey
Did you know?
Melbourne Water treats around 325,308 million litres of sewage at the Eastern Treatment Plant and the Western Treatment Plant each year (2010/11).
So what happens when you flush the toilet or pour something down the sink?
Sewage enters the sewerage system
Sewage from your bathroom, toilet, kitchen, laundry and drains enters the sewerage system via a network of underground pipes. Melbourne’s three retail water companies look after these pipes, which are located along property boundaries and streets.
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Sewage flows to larger sewers
These pipes eventually branch into the large pipes and tunnels which Melbourne Water manages. We call these large pipes Trunk sewers. Most of Melbourne’s sewage is transported in these trunk sewers to either the Eastern or Western Treatment Plant, where it is treated before being recycled or released into the environment.
It can take up to 12 hours for sewage to travel through the extensive network of trunk sewers to reach the treatment plants. The sewers slope downwards so sewage slowly flows along by gravity. Eventually the sewage must be pumped back up to the surface. Pumping stations bring the sewage up to ground level for treatment or to allow it to continue flowing down through the sewerage system by gravity.
Sewage enters treatment plants
Melbourne Water treats around 325,308 million litres of sewage at Eastern Treatment Plant and the Western Treatment Plant each year (2010/11). That’s enough to fill 130,123 Olympic sized swimming pools. It takes around 30 - 40 days for the sewage to pass through the treatment process before being released to the ocean or recycled.