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

Stage one – Demolishing the trickling filters 

We're demolishing the trickling filters and replacing them with a conventional activated sludge reactor. Once up and running, the new reactor will fix the long-standing odour issues. This option also provides opportunities to significantly reduce greenhouse gas emissions and accommodate the needs of our growing population.

Southern Demolition is doing the demolition work, which started in late November 2024 and is expected to be completed by the end of March 2025. Demolition work will happen during working hours, and contractors will do their best to minimise the noise, dust, and traffic disruption. Vehicles will enter the site from Cuthberts Road.

Demolition of both the fire-damaged trickling filters is now largely complete, and we're taking the final steps to prepare the site for the construction of the activated sludge reactor. 

Stage two – Constructing the activated sludge reactor 

The next stage of work will be the construction of the activated sludge reactor. Design work is currently underway, and it’s expected to take up to three years to get the new solution up and running.

We can build the activated sludge reactor without disrupting 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.  

Estimated timeline for design and construction

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. 

April 2025

Demolition of trickling filters complete

Demolition of the trickling filters is 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. 

August 2025

Main contractor awarded

The main contractor for construction of the Activated Sludge Plant will be awarded. 

September 2025

Mechanical and electrical design complete

The entire design for the Activated Sludge Reactor including mechanical and electrical components is complete. 

September 2025

Site establishment

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

February 2026

Construction begins

Construction of the Activated Sludge Reactor will begin. 

January 2028

Commissioning process begins

We'll start the process of decommissioning the temporary plant and commissioning the new plant. This will take until the end of 2028.