North Head biosolids upgrade project

Improving the way we process biosolids

To improve the way we process biosolids at our North Head Water Resource Recovery Facility, we're building 2 new digesters and upgrading equipment. Biosolids are used in agriculture to fertilise soil.

About this project

Project timeline

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FAQs

About this project

The North Head Water Resource Recovery Facility serves over one million Sydneysiders: from Seven Hills in the west, Yagoona in the south, and Ku-ring-gai and Collaroy in the north. It produces organic solids (sludge) as a by-product of the wastewater treatment process. This sludge is collected and processed to convert it into a safe, stable, nutrient-rich fertiliser product called biosolids.

Each year, we produce around 180,000 tonnes of biosolids from our water resource recovery facilities. That's over 9,000 full busloads. Find out more about how we make and recycle biosolids.

We're building 2 new digesters and upgrading equipment to improve how we process biosolids at our North Head facility.

Benefits

Less odour

Building 2 new digesters and upgrading equipment will improve the quality of biosolids we produce. Better quality biosolids means they will smell less. There will be less odour as our trucks transport biosolids from North Head to farms in regional NSW.

Ongoing reliability

The new digesters and upgrades to sludge tanks will ensure the ongoing reliability of the facility. The digesters will increase sludge processing from 40 to 70 tonnes per day by 2043.

Reducing our environmental footprint

Producing biosolids helps us reduce our environmental footprint and contribute to a circular economy by:

  • minimising the discharge of solids to our oceans and rivers
  • recycling a valuable resource that helps minimise disposal to landfill
  • reducing the amount of chemical fertilisers used on farms
  • producing biogas used to generate renewable energy to power our treatment facilities.

Impacts

All construction will take place within the existing North Head facility. You won't see, smell or hear our work. You may notice more trucks transporting equipment, people and materials at different stages of construction.

The North Head facility operates 24 hours a day, 7 days a week. Our construction work hours for this project are 7am–6pm Monday to Friday and 8am–1pm on Saturdays (except public holidays).

Project timeline

2018: Review of Environmental Factors display
The Review of Environmental Factors (REF) was displayed for community comment.
2019: Detailed planning
We prepared in-depth plans and costs for construction.
2020: Securing funding
Funding for the delivery of 2 new digesters and upgrades to biosolids processing equipment was approved.
2021: Finalising designs and preparing for construction
We've been working behind the scenes with Confluence Water, our delivery partner, to finalise designs and prepare for construction to start in late 2021.
2021: Construction starts
Construction is expected to continue until late 2025.

Project updates

13 December 2023
Crane removal out of hours

Now that the 2 new digesters are finished, we need to remove the tower crane from our site.

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01 June 2023
Our 2 new digesters are now finished!

We recently finished an important milestone for our biosolids upgrade project – construction of our 2 new digesters is now finished.

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09 March 2023
Concrete pour planned for 14 March 2023

We've completed 9 of the 10 concrete pours for the new digesters so far.

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16 February 2023
Concrete pour planned for 22 February 2023

We've completed 8 of the 10 concrete pours for the new digesters so far.

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02 February 2023
Concrete pour planned for 7 February 2023

We've completed 8 of the 10 concrete pours for the new digesters so far.

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07 December 2022
Concrete pour planned for 15 December 2022

We've completed 7 of the 10 concrete pours for the new digesters so far.

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30 November 2022
Concrete pour planned for 7 December 2022

We've completed 6 of the 10 concrete pours for the new digesters so far.

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02 November 2022
Concrete pour planned for 9 November 2022

We've completed 5 of the 10 concrete pours for the new digesters so far.

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20 October 2022
Concrete pour planned for 27 October 2022

We've completed 4 of the 10 concrete pours for the new digesters so far.

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13 September 2022
Concrete pour planned for 20 September 2022

We've completed 3 of the 10 concrete pours for the new digesters so far.

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18 August 2022
Concrete pour planned for 25 August 2022

We've completed 2 of the 10 concrete pours for the new digesters so far.

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17 June 2022
Concrete pour planned for 24 June 2022

There are 10 major concrete pours planned over the next 9 months to build the 2 digesters.

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18 March 2022
Relocating the cogeneration engine

We have 2 cogeneration engines at North Head that meet some of the facility's energy needs. We capture biogas from the anaerobic digesters and use it to power a combustion engine that drives an electrical generator.

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17 February 2022
Crane delivery out of hours

We need to bring a large crane to site early in the morning when the roads are quiet, in line with Transport for NSW requirements.

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15 November 2021
Construction has started!

The North Head biosolids upgrade project is now in progress.

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FAQs

In 2019, we refined concept designs and started detailed planning to determine project scope, timing and budgets. Detailed plans identified that the project budget exceeded anticipated funding and we decided to split the project into 2 parts, primarily for funding purposes and to manage the scope, timing and deliverables better. 

Delivering this project in 2 phases helps us better plan with and around other projects and upgrades at the North Head facility, safely coordinate crew movement, and minimise cumulative impacts to the local Manly community. 

Deliveries will generally be scheduled within our work hours, but there will be certain activities that require heavy equipment and oversized vehicles to travel to and from the site outside our work hours, in line with Transport for NSW requirements (if they need to be off the road by a certain time). This won't happen every day and will be spread out over the entire construction period, mainly as we build the 2 new digesters. We will also install a tower crane on-site to minimise the frequency of mobile cranes coming to and from the site.;

We're committed to being a good neighbour and reducing noise and vehicle movements for the community. We'll let directly impacted residents know in advance when we bring oversized vehicles or equipment to site outside our work hours.

Since the North Head facility operates 24 hours a day, 7 days a week, there are already Sydney Water vehicles travelling to and from the site as part of our operation and maintenance activities. We don't expect the biosolids project to create a significant increase in traffic on local roads during construction.

The circular economy concept involves reusing, repairing and recycling materials, designing out waste and pollution, and keeping products in use for as long as possible. A circular economy moves us away from single-use materials and unsustainable forms of consumption.

We aim to create a better life with world-class water services, and are champions for the environment, public health and resilience. We create value for our customers and communities by embracing circular economy practices with the use of water, energy and materials to restore and regenerate the natural environment.  

We'll do this by:

  • recovering and reusing resources wisely and reducing waste to landfill
  • exploring innovative waste management strategies
  • harnessing research and innovation to increase our use of renewable energy.