Sustainability Report 2006/07Overview
Melbourne Water’s sewerage system includes the city’s major sewage treatment plants – the Eastern Treatment Plant at Bangholme and the Western Treatment Plant at Werribee – 399 kilometres of sewers and three major pumping stations.
The retail water businesses collect sewage and trade waste from households and businesses, which is sent for treatment at the Melbourne Water treatment plants. They also manage pollutants in industrial sewage through trade waste agreements with industry.
Meeting the challenge of climate change
Our sewage treatment plants play a key role in meeting our sustainable water vision. We regard water flowing into these plants as a resource, not a waste product, and water recycling as an important way of conserving precious drinking water.
To enable more water to be recycled, and to meet our licence requirements and community expectations, we delivered a range of process and environmental improvements at these plants this year as part of responding to climate change.
Another year of low inflows
The impacts of drought are well understood when it comes to our water storages but below average rainfall and water conservation measures also reduce the amount of sewage flowing into our treatment plants.
During the year, an average of 312 million litres of sewage a day flowed into the Eastern Treatment Plant, and 435 million litres of sewage a day flowed into the Western Treatment Plant.
These plants treated a total of 272,881 million litres of sewage this year, compared with 299,955 million litres the previous year. This significant reduction is a result of the drought and the excellent water conservation efforts of Melburnians with greywater reuse an increasingly popular conservation measure in homes and businesses around Melbourne.
Among the impacts of lower inflows were elevated algae levels in the Western Treatment Plant lagoons and some difficulties in supplying recycled water customers (see Recycled water).
Metropolitan Sewerage Strategy
Melbourne Water and the retail water businesses continued developing a Metropolitan Sewerage Strategy. A scenario planning framework was developed and piloted. Critical issues and uncertainties that are likely to be assessed in the next phase include future climate change impacts, population growth, community expectations, technology development and markets for resources from sewage. The strategy is expected to be completed by December 2009.