November 2021
- On 1 November 2021, emergency services respond to a fire at the Wastewater Treatment Plant in Bromley. Both of the trickling roof filters collapse. The damage couldn't be assessed properly until the fire was completely out.
- On 4 November, the Council installed a sprinkler system to remove hot spots and help reduce the smell. We also begin working on an adaptive management plan to figure out the best possible outcome for the discharge of wastewater from the plant.
- On 26 November, the fire is officially completely extinguished by the fire service. The Council identifies the need to remove the two trickling filters. Both filters store 13,000 cubic metres of material.
- The Council started using misters and polyaluminium chloride - an odourless powder that dissolves in water - to help suppress the smell. Polydosing also settles more of the suspended solids in the wastewater, improving the water quality as it progresses through the plants.
- Hydrogen peroxide - a compound that naturally breaks down into water and oxygen – starts to be added to the wastewater before it’s discharged into the oxidation ponds.
December 2021
- On 6 December, the Council completed a successful trial to remove a section of the fire-damaged media from the plant. This means the Council could begin assessing the stability of the structures.
- On 17 December, Council staff planned to convert two of the plant’s four clarifier tanks (or secondary contact) into aeration tanks. Installing four aerators in each of the two tanks will help decrease the bad smells and improve the quality of the wastewater being discharged. The Council anticipated that it would be years before the trickling filters could be replaced or rebuilt.
February 2022
- On 14 February, aeration components begin to arrive to implement the interim plan to minimise odours from the fire-damaged plant.
March 2022
- On 16 March, eight aerators are installed in two of the plant’s four clarifiers.
- Soon afterwards, increased odours from the trickling filters are detected after wet weather. It's determined that the acute stench is caused by the material inside the trickling filters rotting and drying out.
April 2022
- On 6 April, the aerators installed in March are turned on.
- On 12 April, the Council decided to fast-track the appointment of a contractor to remove the burnt filter material.
May 2022
- Filter media removal work starts.
- On 6 May, independent testing to better understand the odours from around the fire-damaged plant detects small amounts of hydrogen sulphide and methyl mercaptan.
- On 26 May, the Council confirms a community support package for 3,380 of the most affected residents.
June 2022
- Southern Demolition and Salvage Limited conducted a test run, removing and transporting the burnt trickling filter material on Friday 3 and Saturday 4 June.
- Work to remove the trickling filter began on 6 June.
July 2022
- The new activated sludge treatment process becomes fully operational at the plant.
- This new system pumps wastewater from the converted aeration basins to the clarifiers, which greatly improves the quality of the wastewater.
August 2022
- Trickling filters are emptied one month ahead of schedule.
September 2022
- Odours from the oxidation ponds are expected to reduce from September, although it is expected that some odours will remain for most of the month. These will progressively reduce as the pond's health improves.
April 2023
- A project to increase the biological health of Pond 1 is completed after 16 aerators are installed and turned on, churning more than 300kg of oxygen into the pond every hour.
- In the long term, these aerators will ensure the entire pond continues to stay healthy and function well.
May 2023
- The disc aerators on Pond 1 failed and were in the process of getting repaired.
Late 2023
- Fencing around oxidation ponds was installed to improve safety and reduce rubbish entering ponds. Subsequent minor changes were made to deter birds and improve effectiveness.
- Insurance negotiations were continuing.
- In November, a report on the insurance claim for the November 2021 fire was provided to the Council.
- In December, aerators on Oxidation Pond 1 restarted to minimise odours.
March 2024
- A report on the insurance process and odour mitigation efforts was provided to the Council.
- Odour mitigation plan released.
- Odour mitigation work is underway. Various actions taken to improve plant performance and reduce odour.
- A new interactive map was created showing odour mitigation work.
April 2024
- Ponds switched to winter operation mode. Adjustments made to our operations to reduce odours when the biology changes as weather cools.
May 2024
- The Mayor and councillors approved a grant of $130,000 to resource a project with the goal of strengthening and sustaining effective and respectful relationships with Eastern Communities.
- Completed work to cover inlet chambers to contain odour.
- Completed replacement of the bio-bed material in the odour control system. Old material reused as soil conditioner for native planting areas.
October 2024
- Christchurch City Council and its insurers have agreed on a settlement in relation to the fire-damaged trickling filters at the Christchurch Wastewater Treatment Plant.
- The Council also approved the replacement of the trickling filters with an activated sludge reactor.
- This significant milestone allows us to move forward with building a resilient and more environmentally friendly wastewater treatment plant for our growing city.
- Replacing the trickling filters with an activated sludge reactor will give the Council the opportunity to significantly reduce greenhouse gas emissions. Additionally, activated sludge reactors can deliver better environmental outcomes and have a smaller footprint that can be cost-effectively upsized to accommodate the needs of our growing population.
- Design work is underway and it’s expected to take up to three years to complete the design and construction of the new activated sludge reactors.
November 2024
- Demolition of the Christchurch Wastewater Treatment Plant’s fire-damaged trickling filters started.
- Southern Demolition is doing the work, which is expected to take four to five months to complete.
- The demolition is the first stage of physical work to replace the filters with an activated sludge reactor, which will fix long-standing odour issues.
April 2025
- Demolition of the trickling filters was completed making way for construction to begin on the the new activated sludge reactor later this year.
November 2021
- On 1 November 2021, emergency services respond to a fire at the Wastewater Treatment Plant in Bromley. Both of the trickling roof filters collapse. The damage couldn't be assessed properly until the fire was completely out.
- On 4 November, the Council installed a sprinkler system to remove hot spots and help reduce the smell. We also begin working on an adaptive management plan to figure out the best possible outcome for the discharge of wastewater from the plant.
- On 26 November, the fire is officially completely extinguished by the fire service. The Council identifies the need to remove the two trickling filters. Both filters store 13,000 cubic metres of material.
- The Council started using misters and polyaluminium chloride - an odourless powder that dissolves in water - to help suppress the smell. Polydosing also settles more of the suspended solids in the wastewater, improving the water quality as it progresses through the plants.
- Hydrogen peroxide - a compound that naturally breaks down into water and oxygen – starts to be added to the wastewater before it’s discharged into the oxidation ponds.
December 2021
- On 6 December, the Council completed a successful trial to remove a section of the fire-damaged media from the plant. This means the Council could begin assessing the stability of the structures.
- On 17 December, Council staff planned to convert two of the plant’s four clarifier tanks (or secondary contact) into aeration tanks. Installing four aerators in each of the two tanks will help decrease the bad smells and improve the quality of the wastewater being discharged. The Council anticipated that it would be years before the trickling filters could be replaced or rebuilt.
February 2022
- On 14 February, aeration components begin to arrive to implement the interim plan to minimise odours from the fire-damaged plant.
March 2022
- On 16 March, eight aerators are installed in two of the plant’s four clarifiers.
- Soon afterwards, increased odours from the trickling filters are detected after wet weather. It's determined that the acute stench is caused by the material inside the trickling filters rotting and drying out.
April 2022
- On 6 April, the aerators installed in March are turned on.
- On 12 April, the Council decided to fast-track the appointment of a contractor to remove the burnt filter material.
May 2022
- Filter media removal work starts.
- On 6 May, independent testing to better understand the odours from around the fire-damaged plant detects small amounts of hydrogen sulphide and methyl mercaptan.
- On 26 May, the Council confirms a community support package for 3,380 of the most affected residents.
June 2022
- Southern Demolition and Salvage Limited conducted a test run, removing and transporting the burnt trickling filter material on Friday 3 and Saturday 4 June.
- Work to remove the trickling filter began on 6 June.
July 2022
- The new activated sludge treatment process becomes fully operational at the plant.
- This new system pumps wastewater from the converted aeration basins to the clarifiers, which greatly improves the quality of the wastewater.
August 2022
- Trickling filters are emptied one month ahead of schedule.
September 2022
- Odours from the oxidation ponds are expected to reduce from September, although it is expected that some odours will remain for most of the month. These will progressively reduce as the pond's health improves.
April 2023
- A project to increase the biological health of Pond 1 is completed after 16 aerators are installed and turned on, churning more than 300kg of oxygen into the pond every hour.
- In the long term, these aerators will ensure the entire pond continues to stay healthy and function well.
May 2023
- The disc aerators on Pond 1 failed and were in the process of getting repaired.
Late 2023
- Fencing around oxidation ponds was installed to improve safety and reduce rubbish entering ponds. Subsequent minor changes were made to deter birds and improve effectiveness.
- Insurance negotiations were continuing.
- In November, a report on the insurance claim for the November 2021 fire was provided to the Council.
- In December, aerators on Oxidation Pond 1 restarted to minimise odours.
March 2024
- A report on the insurance process and odour mitigation efforts was provided to the Council.
- Odour mitigation plan released.
- Odour mitigation work is underway. Various actions taken to improve plant performance and reduce odour.
- A new interactive map was created showing odour mitigation work.
April 2024
- Ponds switched to winter operation mode. Adjustments made to our operations to reduce odours when the biology changes as weather cools.
May 2024
- The Mayor and councillors approved a grant of $130,000 to resource a project with the goal of strengthening and sustaining effective and respectful relationships with Eastern Communities.
- Completed work to cover inlet chambers to contain odour.
- Completed replacement of the bio-bed material in the odour control system. Old material reused as soil conditioner for native planting areas.
October 2024
- Christchurch City Council and its insurers have agreed on a settlement in relation to the fire-damaged trickling filters at the Christchurch Wastewater Treatment Plant.
- The Council also approved the replacement of the trickling filters with an activated sludge reactor.
- This significant milestone allows us to move forward with building a resilient and more environmentally friendly wastewater treatment plant for our growing city.
- Replacing the trickling filters with an activated sludge reactor will give the Council the opportunity to significantly reduce greenhouse gas emissions. Additionally, activated sludge reactors can deliver better environmental outcomes and have a smaller footprint that can be cost-effectively upsized to accommodate the needs of our growing population.
- Design work is underway and it’s expected to take up to three years to complete the design and construction of the new activated sludge reactors.
November 2024
- Demolition of the Christchurch Wastewater Treatment Plant’s fire-damaged trickling filters started.
- Southern Demolition is doing the work, which is expected to take four to five months to complete.
- The demolition is the first stage of physical work to replace the filters with an activated sludge reactor, which will fix long-standing odour issues.
April 2025
- Demolition of the trickling filters was completed making way for construction to begin on the the new activated sludge reactor later this year.