We're replacing the fire-damaged trickling filters with an activated sludge reactor.

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Once up and running, the new reactor will fix the long-standing odour issues experienced since the fire. It will also reduce greenhouse gas emissions and accommodate the needs of our growing population.

We can build the activated sludge reactor with minimal disruption to current operations. In the meantime, we’re working hard to keep the damaged plant operating with minimal odour and will keep the community updated on progress.

Construction underway

Our contractor HEB Construction is now active on site. Bulk earthworks are now underway, which involve site material being removed and gravel being brought on site.

Once the team has excavated down to about two metres, they will begin installing the stone columns that help stabilise the ground. This part of the job will take a few months.

After that, they’ll build the load transfer platform, which brings the ground level back up and prepares the area for the construction of the plant. This phase is expected to take around six months.

The programme is expected to take about three years, with commissioning targeted for 2028. We can build the activated sludge reactor with minimal disruption to current operations.

Noise, dust and traffic management

Here’s what you need to know about noise, dust and traffic management:

  • Noise and vibration will be monitored at the site boundary, with strict limits in place. If these limits are exceeded, mitigation measures will be put in place.
  • Dust control will include visual monitoring, water carts, speed limits, and other suppression techniques to keep dust to a minimum.
  • Traffic management is being planned with HEB’s ground improvement subcontractor to reduce impacts on the community. During ground improvement work, there may be up to 30 trucks per day coming to the site. We haven't yet confirmed the route trucks will take to the site, but we will share this once we know.

Work hours will be Monday to Saturday, 7.30am to 6pm. If any work needs to happen outside these hours, we'll notify the community in advance.

The new reactor will be a substantial structure, 67m x 67m and 7m high, housing a blower room to mix air with incoming wastewater. The design process has been accelerated by working closely with contractors and using 3D design technology. Our goal is to move quickly, with commissioning of the plant currently targeted for 2028.

Check out the latest timelapse video, from February 2026.

September 2024

Design consultant engaged

Aecom has been engaged to provide the detailed design of the Activated Sludge Plant. 

November 2024

Demolition of trickling filters begins

Work to demolish the trickling filters started on 21 November 2024. Southern Demolition is carrying out the work, which is expected to take around five months to complete.

February 2025

Design scope confirmed

All relevant design elements confirmed. 

March 2025

Demolition of trickling filters complete

Demolition of the trickling filters was expected to be complete by April. 

May 2025

Site prepared for construction

The site will be prepared and made safe, ready to be handed to the main contractor. 

May 2025

Structural design complete

The majority of the activated sludge reactor design is complete and ready for tender. 

September 2025

Mechanical and electrical design complete

The entire design for the activated sludge reactor, including mechanical and electrical components, is complete. 

November 2025

Main contractor awarded

The main construction contract awarded to HEB Construction.

January 2026

Site establishment

The main contractor will set up on site in preparation for construction. 

February 2026

Construction begins

Construction of the activated sludge reactor begins, with the bulk earthwork started. This will be completed in four stages and is expected to finish around early April 2026 .  

April 2026

  • The installation of approximately 1400 stone columns begins. This will take approximately four months to complete.
  • Installation of the reactor discharge pipe and the Returned Activated Sludge (RAS) line commences. This is expected to be completed in late October.

June 2026

Work to install an engineered gravel platform begins.  

August 2026

  • The engineered gravel platform work is expected to be completed.
  • Construction of the concrete structure for the new reactor begins. This is a major part of the project and will take around one year to complete.

October 2026

  • Installation of the reactor discharge pipe and the Returned Activated Sludge (RAS) line expected to be completed.
  • The process to install the supply pipes from the existing pump station to the new plant begins. Due to the pipes’ depth, sheet piling will be required for all underground pipes. This will be completed around March 2027.

2027

  • Construction of the blower hall begins. This will house the blowers and electrical room. It will be constructed with precast concrete panels. This will take around four months to complete.
  • The installation of the supply pipes from the existing pump station to the new plant will finish up around March.
  • The blower hall is expected to be completed around April.
  • Installation of all the equipment and pipes required to operate the new plant will commence. This will start with the blower hall fit-out and then move on to the reactor.
  • Pumps and pipework in the existing pump station will be replaced to accommodate the new plant.
  • Construction of the concrete structure for the new reactor is expected to be completed around August 2027.

2028

Commissioning process begins
  • Commissioning the new plant and replacing the remaining two pumps in the pump station will begin. This will enable us to shut down the existing temporary activated sludge plant and prepare to return the two clarifiers to their original purpose.
  • Removing the temporary plant and making any repairs to the clarifiers and other equipment to return them to normal duty.
  • The entire project is expected to be completed in late 2028.

Check out this timelapse video of the trickling filters being demolished.