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Melbourne's water
storages are currently at:
41.7%
breakdown by reservoir
(you can click on each reservoir
for more information)
Thomson: 27.1%
Cardinia: 43.3%
Upper Yarra: 69.4%
Sugarloaf: 83.4%
Silvan: 89.3%
Tarago: 60.4%
Yan Yean: 54.1%
Greenvale: 66.5%
Maroondah: 100.0%
O'Shannassy: 100.0%
eastern treatment plant
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Today, the Eastern Treatment Plant treats 40% of Melbourne's sewage, or about 312 million litres a day. It serves about 1.5 million people in Melbourne's south-eastern and eastern suburbs.
The plant has been continually improved over the years to include the latest technology.
Sewage treatment at Eastern Treatment Plant
Aerial view of the Eastern Treatment Plant
Sewage is treated naturally at the Eastern Treatment Plant.
We filter large objects using screens and remove other solids using sedimentation. We use bacteria in different types of environment to break down organic material and to remove nutrients.
A small amount of chlorine is added at the end to disinfect the water, so that it is ready to be re-used or to be released to the environment.
Here’s how it works in more detail...
Sewage arrives at the Eastern Treatment Plant and is pumped through fine screens. This removes things like sanitary products, cotton buds, rags and other rubbish. The sewage is aerated to remove finer particles, like grit or sand.
The filtered sewage then flows into primary sedimentation tanks, where more items are allowed to settle out of the sewage. Heavy items sink to the bottom forming a layer we call sludge. Lighter items, such as fats and oils, float to the top of the tank. The settled sludge and floating debris is pumped to larger tanks, known as digesters, where it is later broken down by bacteria.
The primary-treated water flows through to the secondary treatment process. Here, different types of bacteria exist side by side in aerobic (with oxygen) and anaerobic (without oxygen) environments, breaking down organic material and removing nutrients in the plant's aeration tanks. The water passes to round sedimentation tanks, where again, sedimentation settles out more sludge to produce a final, clear effluent.
The treated effluent flows to large holding ponds before it flows through three millimetre microscreens for a final screening process. Just before the treated effluent flows out of the plant to be re-used or released to the environment, it is disinfected with chlorine.
An increasing amount of treated effluent is recycled. The rest is released to the environment at Boags Rocks under an EPA Victoria licence, together with treated effluent from South East Water's treatment plants at Rosebud, Mornington and Hastings.
Protecting the environment at Eastern Treatment Plant
Tertiary upgrade
In October 2006, the Government announced a major upgrade of the Eastern Treatment Plant. By end-2012, the Eastern Treatment Plant will be treating sewage to a tertiary standard. This will improve the health of the marine environment and open the door to more recycling in future.
Improving the marine environment at Boags Rocks
We have learnt that ammonia from the Eastern Treatment Plant has an impact on the marine environment at Boags Rocks, where treated effluent is released.
We have already begun a major project to reduce the amount of ammonia in treated effluent. The aeration tanks at the plant are being improved to help us do this.
A major upgrade to the plant will improve this even more, by the end of 2012.
Water recycling
Using recycled water where it is appropriate means that less treated effluent is being released to the ocean. This also helps us conserve our precious drinking water supplies.
At the plant, recycled water is used in the plant's every day operations to clean screens, to wash down work areas, for cooling and to water the grounds.
We have also been selling recycled water from the plant since the 1970s for use in farms, market gardens, vineyards, golf courses and sporting grounds in Melbourne's east.
Brief history
Melbourne grew quickly in the 1950s and 1960s, especially in the south-eastern and eastern suburbs. To cope with this, the Melbourne Metropolitan Board of Works built a second sewage treatment plant at Bangholme.
When it opened in 1975, the Eastern Treatment Plant was a world leader in the secondary treatment of sewage. Covering 1100 hectares, the plant was the biggest of its type in Australia. It also treated sewage to a standard not available in any other Australian city. At the time, primary treatment was the standard treatment used in Australia and around the world.
A virtual tour of the Eastern Treatment Plant
The Eastern Treatment Plant Explorer is perfect for those who can't visit the site in person. The virtual tour takes you on a virtual journey around the plant, allowing you to easily follow the sewage treatment process and learn about recycled water.