23 July 2009
NEXT STEP IN EASTERN TREATMENT PLANT UPGRADE
KEY POINTS
- Plant upgrade to cut impact of treated effluent on Bass Strait
- Will generate Class A recycled water from end-2012
- New treatment approach may unlock $400m infrastructure saving
- EPA approval required
Melbourne Water’s Eastern Treatment Plant, in Bangholme, is set to become one of the most sophisticated sewage treatment facilities in the world by the end of 2012.
General Manager of Asset Planning, Paul Pretto, said a year of high-tech trials had culminated in a new understanding of how the 34 year-old facility could be upgraded to virtually eliminate impacts of treated effluent discharged into Bass Strait, near Gunamatta.
The improved treatment process will also open the door to a wider range of water recycling uses over time and could save up to $400 million in infrastructure costs.
“Melbourne has a long-held reputation as a leader in managing sewage, especially in reducing impacts of treated effluent on the marine environment,” said Dr Pretto.
“The Eastern Treatment Plant was leading edge when it was built in 1975 and we’ve made ongoing improvements since then, but it needs an overhaul to meet the longterm objectives set out in the State Environment Protection Policy.
“We’ve recently completed 12 months of technology trials to find the best treatment method for sewage coming into the plant.
“The trials have been very successful and they have reshaped our thinking about how we can best meet our obligations to the environment and the community,” he said.
An upgrade of the Eastern Treatment Plant was approved by EPA Victoria in 2002, but was deferred by agreement until feasibility studies into treated water reuse and technology trials were finished.
Dr Pretto said Melbourne Water had now made a fresh submission to EPA Victoria, seeking their approval for a revised upgrade – which focussed exclusively on advanced sewage treatment to improve the marine environment instead of also relying on a 2 kilometre extension to an underwater outfall.
“Our trials showed huge strides in cost-effective treatment technology since 2002. It means we can achieve the environmental outcomes required, plus open the door to more recycling over time, at a significantly reduced cost.”
“We are asking EPA to consider an upgrade that doesn’t include an outfall extension but instead delivers higher quality treated water to permanently reduce factors like colour, odour, ammonia and foaming,” he added.
Dr Pretto said the outfall extension itself would cost $400 million, involve underwater tunnelling and take up to six years. As the treatment upgrade would also be required under this scenario, the total project cost would be around $780 million. The standalone advanced treatment approach preferred by Melbourne Water will cost $380 million.
“The original outfall extension proposal was based on a basic trench construction method, which independent studies have since shown to be unfeasible. Instead of cutting a trench through the beach and the reef, and trying to manage the high surf conditions, we would need to tunnel,” he said.
“We acknowledge that our preference not to extend the outfall and instead focus on better treatment represents a significant shift, which the EPA will need to consider in detail.”
The Eastern Treatment Plant currently produces ‘Class C’ recycled water. The upgrade will boost this to Class A, which can be used more widely, including for toilet flushing, irrigating vegetables, and watering sports grounds.
“Melbourne Water strongly supports recycling for non-drinking purposes and we’re working with government and water retailers on the challenge of how to deliver more of it to customers.”
South East Water and Melbourne Water have identified projects that will utilise a further 7 billion litres of Class A recycled water from the plant when the upgrade is complete in 2012. A range of projects are being investigated to use up to 40 billion litres a year in total over the next 30 years.
For a summary of Melbourne Water’s preferred upgrade approach, visit the Melbourne Water website.
Media Contact: Andrew McGinnes +613 9235 7277 +61 (0)403 930 846