Christchurch City Council announced plans to replace fire-damaged trickling filters at the Christchurch Wastewater Treatment Plant with an activated sludge reactor, aiming to resolve ongoing odour issues affecting the Bromley community. The decision followed the settlement of an $85 million insurance claim, covering damages from a 2021 fire that destroyed the trickling filters, a key part of the plant’s sewage treatment process.
The insurance settlement, approved unanimously by the councillors, came after lengthy and complex negotiations. Due to confidentiality during these talks, there had been uncertainty among residents regarding a long-term solution to the fire damage. Mayor Phil Mauger acknowledged the challenges faced by the community, saying, “From the day the fire started, the community has been impacted by the loss of these trickling filters. The stench caused by the interim solution was unbearable.”
Mauger assured residents that the Council had worked diligently behind the scenes to secure a positive outcome, adding, “We owe it to the people of Christchurch, particularly the surrounding residents, to remove what’s left of the filters and construct an up-to-date new activated sludge system which I am told is lightyears better for treatment and odour control.”
The activated sludge reactor is expected to take approximately three years to become operational. The timeline includes one year for design, followed by two years of construction. Interim operations will continue during the build, aiming to minimise disruption to wastewater treatment services. The new system promises improved resilience, better odour control, and a smaller environmental footprint compared to the old trickling filters.
Mayor Mauger said the new system would benefit the city’s future. “The trickling filters are 50 years old, and in that time, technology has moved forward in leaps and bounds. This new activated sludge system will allow us to significantly reduce emissions and can be upsized at a lower cost to accommodate our growing population,” he said.
The total estimated cost for the new system stands at $140 million, subject to refinement during the detailed design phase. Funding for the project is already included in the Council’s Long Term Plan, ensuring no impact on rates for residents. In the meantime, efforts continue to manage the plant’s interim operations and keep odour levels under control.
“We’re working hard to keep the damaged plant running with minimal odour and will continue to keep the community updated on progress,” said Mauger. He also recognised the challenges of maintaining the damaged plant but praised the Council’s experienced team for their ability to adapt to the situation.
Christchurch City Council has also committed to ongoing efforts to improve plant operations and will continue weekly monitoring of hydrogen sulphide levels around the facility.
