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Replacement Flows Project

Project contact
You can email the
Replacement Flows Project
team, call 1800 506 633 or
write to:
Replacement Flows Project
PO Box 653
St Marys NSW 1790









Overview of the scheme. Click for a larger version
Overview of the scheme.
Click for a larger version










Image of St Marys Recycled Water Plant. Click for a larger version
Image of St Marys
Recycled Water Plant.
Click for a larger version













Image of Hawkesbury-Nepean River
Hawkesbury-Nepean River

The Replacement Flows Project is Sydney's largest water recycling project. It is a key part of the NSW Government's Metropolitan Water Plan. It will play a critical role in increasing water recycling in the Sydney region to 70 billion litres a year by 2015.

How will the project work?

The Replacement Flows Project is designed to save drinking water and maintain river health. It will provide up to 18 billion litres of highly treated recycled water each year to the Hawkesbury-Nepean River system, replacing water currently released from Warragamba Dam to maintain environmental flows.

Wastewater from St Marys, Penrith and Quakers Hill sewage treatment plants will be treated at a new recycled water plant next to St Marys Sewage Treatment Plant.

Sydney Water has built pipelines between the treatment plants to carry treated wastewater and recycled water. After treatment at St Marys, the highly treated recycled water will be pumped back to Penrith and released into the Hawkesbury-Nepean River below Penrith Weir.

Sydney Water has upgraded an existing pipeline between Quakers Hill and Seven Hills to carry concentrate waste from the recycled water plant. We have also built a pipeline from Seven Hills to Oatlands to connect with the northern Sydney sewerage system.

Deerubbin WaterFutures, a consortium of companies consisting of United Group Infrastructure, McConnell Dowell Constructors (Aust) and GE Water and Process Technologies, is work with Sydney Water to deliver this major water recycling project.

What is the timetable for the project?

Construction of the pipelines and recycled water plant started in May 2008 and is nearing completion.

All major construction on the recycled water plant, except for the reverse osmosis membranes, should be finished by January 2010. An extensive program of testing will take place over the coming months. We plan to start releasing test flows of purified recycled water into the Hawkesbury-Nepean River, via Boundary Creek in Penrith, from March 2010.

The plant is scheduled to become fully operational from July 2010.