Downer delivers best practice nutrient removal upgrade at Winmalee Sewerage Treatment Plant

23/07/2024

It is positive news for the local Hawkesbury-Nepean catchment as Downer nears completion on an upgrade to the Winmalee Sewerage Treatment Plant.

Sydney Water awarded Downer the $50 million Winmalee Pollution Reduction Project contract in 2021. The scope included the delivery of a new inlet works fine screen facility, construction of a new Membrane Bioreactor (MBR) tank and conversion of the existing sequential batch reactors into bioreactors. The team has also built new chemical dosing facilities and upgraded the high and low voltage electrical systems located at the plant.

The facility currently services around 60,000 customers and is located on an escarpment in the foothills of the Blue Mountains. It is an area that is surrounded by natural bushland and home to many native flora and fauna species. 

In 2015, the EPA initiated a Pollution Reduction Program that required Sydney Water to reduce the amount of nutrients being released from the plant. 

Downer’s EGM Water Services, Neal Firth, said the plant was located in an environmentally sensitive area due to its proximity to the wider Hawkesbury-Nepean catchment. 

“The Hawkesbury River is popular with recreational users and there are a lot of primary producers that pump water out of it, so it’s a very important artery for north-western Sydney,” Neal said. 

As part of the project, Downer integrated its advanced Membrane Bioreactor (MBR) technology, which uses biological treatment and membrane filtration for wastewater treatment. MBRs offer a number of advantages over traditional methods, such as their smaller footprint, higher treatment efficiency, better solids removal and importantly, the production of higher quality effluent. 

Downer’s Senior Project Engineer, Mitchell Lewis, said the MBR constructed at Winmalee represented a first for Sydney Water. It was also one of the largest operational MBRs in Australia.  

“We’ve already observed a reduction in nutrient loads in the treated water that is released into the catchment. This is really good news for stream health and the local environment,” Mitchell said. 

As a local resident, Neal is proud that Downer is partnering with Sydney Water to help create better water outcomes for the local community. 

“These latest upgrades are an example of the best practice nutrient removal technology Downer offers water authorities. It is also another way that we are demonstrating our commitment to enabling communities to thrive – today and for future generations,” said Neal.

Downer’s Executive General Manager Water Services, Neal Firth and Senior Project Engineer, Mitchell Lewis, onsite at Winmalee.

The Winmalee Sewerage Treatment Plant is located within the foothills of the Blue Mountains, just outside of Sydney.