Sydney Water has awarded the next major stage of its $2 billion North West Treatment Hub Growth Program, appointing the North West Hub Alliance to deliver Budget 2 of the Riverstone Water Resource Recovery Facility upgrade.
The Alliance – comprising Sydney Water, John Holland, KBR and Stantec – will oversee further expansion works at Riverstone as part of the long-term program transforming wastewater services across Sydney’s rapidly expanding northwest corridor.
With the population in the region forecast to double in coming decades, the upgrade is designed to ensure treatment capacity stays ahead of demand while improving environmental outcomes.
“The population in this corridor is expected to double and this program ensures we are ahead of that growth, delivering reliable services for thousands of families while improving the health of our local waterways,” said Sydney Water Program Director Darren Wharton.
Budget 2 works at Riverstone will include construction of a new liquid treatment stream to increase capacity, installation of a new underground effluent pipeline and connection to a high-voltage electrical supply from the new Grantham Farm Zone Substation.
Once complete, the upgrades will increase treatment capacity by an additional 21ML per day, equivalent to nine Olympic-sized swimming pools and strengthening the network’s ability to service new homes and businesses.
The broader North West Treatment Hub spans Castle Hill, Rouse Hill and Riverstone, and is expected to support wastewater services for around 200,000 homes by 2056.
At Riverstone, the program also includes NSW’s first wastewater carbonisation facility. Using advanced European technology, the facility will convert wastewater byproducts into carbon-rich biochar, contributing to a circular economy approach and reducing the volume of residual waste.
“Our region is growing rapidly and it’s fantastic to see Sydney Water delivering sustainable infrastructure to service the needs of thousands of new families, while also protecting local waterways,” said Member for Riverstone Warren Kirby.
Elsewhere within the hub, a new membrane bioreactor system at Rouse Hill is replacing ageing lagoon infrastructure, increasing treatment performance without expanding the site’s footprint.
Construction on the Riverstone upgrade is expected to begin in March 2027 and take approximately three years. The program’s integrated sustainability approach, which embedded environmental performance across procurement, design and construction, was recently recognised with the 2025 Sustainability Project of the Year award.
