North West Treatment Hub

Upgrades at the Castle Hill WRRF are continuing, and there will be some night work from 10pm Tuesday 24 September 2023 to 7am the next day (Wednesday 25 September), weather permitting.

We need to install some steel plates in one of our large tanks on site. For the safety of workers, we need to complete the work at night because that is when the water flow is low, making it easier to isolate and access.

See more details.

During public exhibition between 17 June and 9 July 2024, community and stakeholders were invited to comment on the proposed changes. We received three submissions.

This Decision Report:

• summarises community and stakeholder consultation undertaken on the proposed change
• considers the comments raised in the submissions
• recommends that Sydney Water proceed with the proposed changes.

We would like to thank everyone who provided feedback.

We have refined these plans and have made some changes to the proposed designs. Most of these won’t have a substantial change in how the project impacts the community. One of the key changes is that we are now proposing to use a more efficient process called carbonisation to treat and reuse biosolids (a by-product of the current treatment process) at Riverstone WRRF.
To provide the community with more detail on the proposed changes, a Review of Environmental Factors Addendum (REFA) has been prepared.
The REFA looks at all the potential benefits and environmental impacts of the project as we build it and once it's up and running. The REFA needs to cover all scenarios, even though there will be opportunities to improve or even eliminate some of these impacts as we continue to fine-tune this project.
It includes:

• the background to this project
• proposed construction activities, including work locations within the Riverstone and Rouse Hill Water Resource Recovery Facilities
• Potential environmental impacts, including noise, traffic and access.

The REFA is on display from Monday 17 June to Tuesday 9 July 2024.

To read the REFA click through HERE

Feedback from the community is invited during this time via email at and you can email us NorthWestTreatmentHub@sydneywater.com.au

You can view and download the REFA from the Document Library.

We will continue to engage with stakeholders and the community throughout the project, and keep you updated on work in your local area.

If you have any questions about our plans, please come along to a community information session or attend our webinar in the coming weeks. We’d love to hear your thoughts – check out the timetable below.

Attend a community event

We’re hosting two community events to share more about our plans.

Online information session

6 – 7 pm, Thursday, 27 June – register here to attend

Community information session:
10 am – 2 pm, Saturday 29 June
Carmel Village, Windsor Rd, Box Hill

If you are unable to attend these sessions you can contact our team by emailing NorthWestTreatmentHub@sydneywater.com.au or by calling 1800 560 682.

We had originally planned to build a new pipeline to transfer partially treated wastewater from Castle Hill WRRF to Rouse Hill WRRF, and from Rouse Hill WRRF to Riverstone WRRF for further treatment.

Sydney Water and the NWHA have refined these plans and have made some changes to the proposed designs. Most of these won’t have a substantial change in how the project impacts the community. One of the key changes is that we are now proposing to use a more efficient process called carbonisation to treat and reuse biosolids (a by-product of the current treatment process) at Riverstone WRRF.

Using this new technology means we won’t need to build the new pipeline to connect the Castle Hill, Rouse Hill and Riverstone WRRFs.

To provide the community with more detail on the proposed changes, a Review of Environmental Factors

Addendum (REFA) has been prepared and will be on public display from 17 June 2024 until 9 July 2024.

Key dates:

17 June to 9 July 2024 Review of Environmental Factors Addendum
July 2024: Site mobilisation and early work to start
Late 2024: Growth Upgrade construction starts

To help improve water quality, odour and cater for growth in the area.

This work includes:

• replacing and upgrading equipment to improve water quality, and odour, and reduce noise
• new facility buildings
• minor extensions to the current fence line
• an additional treated water discharge main to Cattai Creek
• a new high voltage electricity line to connect into the facility.

Our work hours are between 7am and 6pm, Monday to Friday and 8am to 1pm on Saturdays. Where work may be required outside of these hours, we will notify affected residents before the work.

We've cleared away some vegetation, taken down old buildings, emptied a lagoon and reshaped the land to get ready for the next stage of construction. While emptying the lagoon we unexpectedly found, cleaned and released a group of over 80 Eastern Long-necked Turtles, native to Australia and known scientifically as Chelodina longicollis! Read about it in our newsletter sidebar to the right.

Our contractor Abergeldie Complex Infrastructure will soon start the structural works phase, laying the foundations for the new facility. During this time, you might notice:

• some noise and vibration from construction
• increased vehicle and truck movements to and from the site on Wrights Road
• increased number of workers vehicles parking on Wrights Road.

Notification of vegetation removal

To ensure the structural works proceed safely, we’ll be widening the entrance to the site to accommodate large vehicles like trucks. This means, on week of 10 June 2024 we will start vegetation removal along the site’s western boundary, weather permitting.

These changes are outlined in the Addendum Review of Environmental Factors which can be found in the sidebar to the right.

We understand the importance of preserving the environment, so any necessary vegetation removal will be done carefully. After construction is finished, we’ll replant vegetation onsite and offsite, following Sydney Water’s guidelines.

We will do our best to minimise the impacts and continue to keep you updated. Our work hours are between 7am and 6pm, Monday to Friday and 8am to 1pm on Saturdays. Where work may be required outside of these hours, we will notify affected residents before the work.

To find out more on the project

Newsletter – read our latest community update.
Email – northwesttreatmnethub@sydneywater.com.au
Phone – 1800 560 682

The environmental assessment for the Castle Hill WRRF upgrade work was completed in 2021 and the decision to support the project was made in January 2022.

Since then, the project has been changed slightly. An extra environmental assessment was completed covering:

• Works around installing a high voltage power cable
• Changing the location of the high voltage switch room
• Removing the water from and filling in a lagoon no longer required on site.

Most of the work will happen within the existing facility, with some in the area surrounding the facility (while still remaining on Sydney Water property). Some of the work may impact local residents and visitors to the walking and cycling track, including:

• Noise from construction – this will be temporary only and will fluctuate based on the program of work
• Careful vegetation removal and trimming – some additional vegetation removal cannot be avoided as part of this extra work. We will make sure that appropriate actions are in place to ensure safety of wildlife, and plant replacement trees and shrubs towards the end of the project.
• Working on the lagoon may generate some odours, which is unlikely to impact local residents. However, we will be closely monitoring odour and dust during these work activities.

Read the full Review of Environmental Factors Addendum.

The compliance upgrade work at Castle Hill is now underway and will take up to 2 years to complete.

This work will include:

• replacing and upgrading equipment to improve water quality and odour, and reduce noise
• new facility buildings
• minor extensions to the current fence line
• an additional treated water discharge main to Cattai Creek
• a new high voltage electricity line to connect into the facility.

Our work crews and trucks will access the facility from Wrights Road. Drawbridge Place will be used as a secondary access route.

While most of our work will be within the plant boundary, we will be making some adjustments to the walking track along the western boundary (nearest to Wrights Road) to protect the safety of walkers and to make room to complete our work. During the project, a new walking track will be in place adjacent to the existing track. Detour signage will be in place to guide pedestrians and cyclists around the site.

Our work hours are between 7am and 6pm, Monday to Friday and 8am to 1pm on Saturdays. Where work may be required outside of these hours, we will notify affected residents before the work.

Read our latest community update.

The Decision Report from the latest Review of Environmental Factors (REF) has now been published.

This Decision Report:

• considers the comments raised in the submissions
• identifies whether any new mitigation measures or changes to existing mitigation measures are required
• recommends whether Sydney Water should proceed with the proposal.

We would like to again thank everyone who provided their feedback on the REF and attended an information session or contacted us regarding the North West Treatment Hub.

In August 2022, we displayed the Review of Environmental Factors for proposed work to connect 3 treatment plants, with 2 pipelines and upgrades at 2 plants. 

During this time, we held information sessions, in person and online, to give the community an opportunity to speak to us and ask questions.

Thank you to everyone who attended an information session, contacted us and provided feedback.

We are now considering the issues raised. Our next step will be to publish a Decision Report in the coming months, outlining these submissions and our responses to the issues raised.