Proposal would pump 70 million litres of treated wastewater into Parramatta River each day

Sydney Water wants to pump 70 million litres of treated wastewater into the Parramatta River every day, just months after the NSW government spent $1.26 million reopening two swimming sites along the waterway. The volume would equal roughly 35 Olympic-sized swimming pools each day.

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The facility will treat wastewater to an advanced standard using reverse osmosis before releasing.

The proposal involves building a wastewater treatment plant at Camellia-Rosehill in Sydney's west by 2032. A 5.3-kilometre pipeline, mostly running through tunnels, would carry the treated water to an outlet at Meadowbank Park.

Project delivery lead Caine Mertens told the ABC the facility would use reverse osmosis and multiple safeguards before releasing the water. He said the treated wastewater would be cleaner than the river's existing water and would improve local water quality. “The facility will treat wastewater to an advanced standard using reverse osmosis before releasing,” he said. “Water in this project will be treated to a very high level with lots of safeguards, lots of redundancy.”

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Water in this project will be treated to a very high level with lots of safeguards, lots of redundancy.

Sydney Water says its existing infrastructure, which serves about 1.7 million people across western and northern Sydney, will reach capacity by 2031. The new facility would help meet demand from an additional 230,000 people expected to live in the area over the next 30 years. Mertens said the project was about relieving pressure on the wastewater system.

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To put treated water, treated from sewage, into the Parramatta River is actually unbelievable to me.

Ian Wright, a former Sydney Water scientist who now researches water science at Western Sydney University, said reliably treating raw sewage would be difficult. “To put treated water, treated from sewage, into the Parramatta River is actually unbelievable to me,” he said. “Pumps break, filters block. All kinds of things can happen, so you may be able to achieve high quality most of the time, probably not all the time.” The proposal is being assessed as a state significant development application. The planned outlet is downstream from the Bedlam Bay and Putney Beach swimming sites, in an area with mangroves, wetlands and wildlife.

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Pumps break, filters block. All kinds of things can happen, so you may be able to achieve high quality most of the time, probably not all the time.