Three years before new wastewater treatment system operational

Wednesday, 9 October 2024

Diggers working at the burnt-out Bromley wastewater treatment plant after the 2021 fire.

Christchurch’s fire-damaged wastewater treatment plant can now finally be repaired, after almost three years of insurance wrangles.

The city council on Wednesday said it had settled an $85 million insurance claim, and that designs were under way on a $140m plan to fix the plant.

Two trickling filters at the Bromley plant were destroyed by fire on November 1, 2021, taking out 60% of its treatment capacity. The fire burned for 19 days before being brought under control.

Long-time Bromley resident Vickie Walker has questioned why it has taken the council so long to get to this point.

Staff were able to keep the plant operating, but the stench from the damage has tormented residents, causing nausea, headaches, respiratory illness, sleepless nights and affecting the mental health of nearby residents.

The council has decided not to rebuild the trickling filters and will replace them with an activated sludge system, a common and well-known treatment process used worldwide and in New Zealand.

However, it will take three years before the system is operational.

Residents say the odour is not as bad as it was, but they are concerned they have to wait another three years before the issue is completely resolved.

Mayor Phil Mauger said the filters - which he helped build 50 years ago - were old technology.

“The trickling filters are 50 years old, and in that time technology has moved forward in leaps and bounds.”

If the council was to rebuild the filters, it would be building on top of 80-year-old infrastructure, he said.

The Christchurch City Council has decided not to rebuild the trickling filters.

Mauger said it was the best method to treat wastewater from a resilience, growth, sustainability and long-term cost perspective.

The council estimates the new system would reduce treatment plant greenhouse gas emissions by about 75%. The plant is currently responsible for more than 63% of the council’s total gross emissions.

Council chief executive Mary Richardson said the insurance claim only covered the cost of rebuilding the filters, but the additional $55m had already been included in the council’s 10-year budget, the long-term plan, signed off in June.

The design work had already started and the council hoped to start physical work on the new system within six months.

Mauger said he hoped the old filter structures, which remain in place, would be demolished by Christmas.

When asked if that was likely, he joked that he “had a digger”.

Mauger said the last three years had been a distressing time for locals and he acknowledged it had been a lengthy process.

“While confidentiality was necessary throughout the negotiations, it resulted in uncertainty for the community over a permanent solution to the fire damage.

Two trickling filters at Christchurch’s wastewater treatment plant were destroyed by fire on November 1, 2021.

“I want those directly impacted and all Christchurch residents to know that behind the scenes we have been moving heaven and earth to get to this position today.”

Vickie Walker, who has lived in Bromley for 26 years, said she was pleased to hear something was happening, but questioned why it had taken so long and wondered why it was going to take another three years to complete the work.

She said the project should have been included in the Government’s Fast Track Bill to help speed it up.

Walker said the odour is not as bad as it once was, but it still stank at times.

“It’s bad at times, but it’s not bad all the time.”

Christchurch City Council chief executive Mary Richardson, mayor Phil Mauger and head of three waters Gavin Hutchison speak to media about the council’s plans for the wastewater treatment plant.

Environment Canterbury operations director Stephen Hall said there had been 418 complaints about odour coming from the treatment plant this year.

It issued two non-compliance notices to the city council in February and May, but since then the number of complaints had significantly reduced.

Council head of three waters Gavin Hutchison said the council did not ask for the project to be included in the Fast Track Bill because there were no consenting challenges and it would not have had any impact on the project timing.

Richardson said there were several reasons why it had taken three years to get to this point. Numerous reports, designs and costings had to be completed for rebuilding the filters and also for the sludge reactors and then staff had to negotiate a settlement with the insurance company.

During the first year after the fire, staff put all their energy into ensuring the plant kept operating, Richardson said.

Waitai Coastal-Burwood-Linwood Community Board deputy chairperson Jackie Simons said Bromley would be an entirely different suburb by 2027, when the new reactors would be built and the suburb’s other source of odour, the organics plant would be closed and moved to Hornby.

Board chairperson Paul McMahon said while the project was a “win win”, it was still three years away and that would be a “journey for people”.

Late last year, the council was heavily criticised in an independent report for being “too slow” to recognise that the smell was a major issue. It formally apologised over its handling of the community response.

An independent investigation into the fire found it was caused by the ignition of flammable material after subcontractors used “an unauthorised heat source” during repairs to the trickling filter roof.