Community and Environmental Benefits
The way we operate the Western Treatment Plant continues to improve, delivering significant benefits for the community and environment.
In 2004 we completed the largest upgrade of the sewage treatment process in the plant's history in response to findings of a four-year Commonwealth Scientific and Industrial Research Organisation (CSIRO) environment study of Port Phillip Bay. This study looked at ways of protecting the long-term health of the bay.
Melbourne Water responded with a $160 million upgrade to improve the way we run the plant.
Community and environmental benefits include improvements in
- Renewable energy
- Water recycling
- Improved effluent quality
- Improved wet weather capacity
- Reduced odour and emissions
Renewable Energy
Did you know that the Western Treatment Plant is able to generate about 95% of its own annual electricity needs?
Using huge covers over the ponds, methane gas produced as a by-product of sewage treatment is captured and turned into renewable energy. Around 90% of odour emissions from the Western Treatment Plant have been cut since the first methane covers were installed in 1992.
The Western Treatment Plant Community Liaison committee focuses on monitoring the plant’s performance on behalf of the community, as well as its environmental compliance.
By June 2012 the Western Treatment Plant will be energy self-sufficient and able to export electricity to other Melbourne Water sites. AGL Pty Ltd is contracted by Melbourne Water to use the methane to fire gas engines which generate electricity for the plant.
Greenhouse gas and odour emissions are significantly reduced by capturing and using biogas to generate this electricity.
Water Recycling
The Western Treatment Plant produces high quality recycled water for nearby farms, parks and market gardens.
In 2010/11, about 29,972 million litres of recycled water was supplied from the Western Treatment plant. Of this
- about 28,051 million litres of recycled water (mostly Class C) was used to irrigate pasture, manage soil salinity onsite, and to maintain the health of the Ramsar listed wetlands.
- 1921 million litres of recycled water (Class A) was supplied to Southern Rural Water and City West Water for offsite customers.
- Learn more about the different classes of recycled water.
A water recycling disinfection plant was built at the Western Treatment Plant in 2004. This plant treats class C recycled water to class A standard which means this water is suitable for a greater number of uses. Class A recycled water is distributed to water recycling schemes in the nearby Werribee region.
Improved effluent quality
One of the major recommendations of the four-year CSIRO Port Phillip Bay environmental study was to reduce the amount of nitrogen entering the bay by 1000 tonnes per year.
Today, two of our three modern lagoon systems at the Western Treatment Plant have been enhanced by improved technology. Since installing the new technology we have cut nitrogen output to the bay by more than 500 tonnes a year.
Improved wet weather capacity
We are undertaking upgrade works to ensure that the Western Treatment Plant is able to treat larger peak flows during heavy rainfall. The works include:
- constructing a second main sewer to deliver double the amount of raw sewage to the plant.
- building a system to let more sewage into the lagoon system during heavy rainfall.
- building a system to let more treated effluent into Port Phillip Bay during high flows
Reduced odour and emissions
Capturing and using biogas to generate electricity also means greenhouse gas and odour emissions are significantly reduced. In fact, odour emissions have been reduced by 90% since the first methane covers were installed in 1992.
We are continuing to improve the plant to ensure ongoing odour reduction. Our priority is reducing odour from one of our main lagoons (which delivers raw sewage to the lagoon), which is next to the proposed Werribee River park and relatively near to the Werribee South township.
We are also replacing one of our lagoon covers which will be four times the size of the MCG and double the existing area covered across this lagoon.