A bit of history... Before sewerage systems
The old outside cesspit toilets
Melbourne citizens once used cesspit toilets - a wooden toilet seat on a straight pedestal over a hole in the ground. The most important part of these was a lid, which helped to cut down on smells and flies. When the hole filled up, a new one had to be dug.
As the town grew, more people had backyard closet toilets with large cans. About once a week a 'nightman' came up the lane in the night hours and took away the can on his horse drawn cart. This was taken to manure pits or used in market gardens.
Towards the end of 19th century, about 500,000 people in the city were putting up with seepage from cesspits, smelly manure pits and occasional overflows of cans and spills from nightcarts.
Public outrage about the health threat led the Government to set up a Royal Commission in 1889 to investigate the need for a proper sewage system. An English engineer, James Mansergh, was invited to Melbourne to propose a suitable scheme. His plan for a sewage farm at Werribee was modified and then the new Metropolitan Board of Works (set up in 1890) began to build it. The first property was connected to it in August 1897.
Today we use the same system.
Now...
About 50% of Melbourne's sewage, from the city and the northern and western suburbs, still goes to Werribee. The Western Treatment Plant in Werribee, and some of this waste travels up to 35 km. First it goes to a pumping station at Brooklyn where it is raised up about 45 metres to give it a boost. Then gravity pushes it along the pipes, 30 metres underground in some places, to the treatment plant.
Around 40% of sewage is treated by an activated sludge method at the Eastern Purification Plant at Carrum. Both the Western and Eastern treatment plants are operated by Melbourne Water Corporation. There are also a number of local treatment plants for some thousands of people who aren't connected to the major systems. City West Water has one of these in Altona.