$10m contract to remove rotting material from wastewater treatment plant

Friday, 22 April 2022

The Bromley wastewater treatment plant was significantly damaged in a fire in November 2021. (File photo).

A contractor is to be appointed to remove 10 Olympic-size swimming pools worth of rotting material from Christchurch’s fire-damaged wastewater plant and dump it at Kate Valley Landfill.

The Christchurch City Council will appoint the contractor to remove material in the filters using a $10 million interim contract granted by its insurer.

The work is expected to take at least four months, but could take up to seven.

The smell from the Bromley plant is coming from two sources – the trickling filters destroyed by fire on November 1 and the oxidation ponds.

The cause of a water treatment plant fire in Bromley, Christchurch, is still under investigation, says operations manager Adam Twose. (First published February 2022)

* 'Horrendous, foul, toxic stench' from Christchurch wastewater plant worsens

* Work to limit smell from fire-damaged wastewater plant nears completion

The council issued a statement on Friday and said it was working to have both issues resolved “by the summer”.

The rotting material would be taken to Kate Valley Landfill in Canterbury and treated as hazardous substance.

The council’s insurer has accepted the claim for the fire, but a settlement has not yet been reached. Investigations to determine the cause were ongoing.

In response to why the extraction of material from the plant hadn’t already begun, the council said it had to carry out an extensive investigation into the fire and the damage it caused, and work through an insurance claim.

As a result of the fire, poorer quality effluent was being discharged into the oxidation ponds, so the ponds began to smell.

“If you remember Bromley in the 1960s and 70s, that smell would be very familiar,” the statement said.

The bulk of the material to be removed from the filters is a mix of plastic and biomass, which was used to help treat the sewage being processed through the plant. Some of the biomass within the trickling filters is rotting, which was causing the stench.

Any temporary measures to reduce the smell in the meantime “did not stack up”, the council said.

A briefing on Thursday next week would discuss next steps for the plant and would be live-streamed.

The council said it expected to make a further announcement in the next 10 days.