6 Apr 2022

Eight new aerators have been turned on at the fire-damaged Christchurch Wastewater Treatment Plant as the Council’s mid-term recovery plan to address one of the two sources of unpleasant odours reaches its next phase.

The Council has converted two of the plant’s clarifier tanks into aeration basins in an effort to improve the quality of the effluent being pumped into the oxidation ponds

Head of Three Waters, Helen Beaumont, says the independent expert advice the Council has received is that these measures will gradually improve the odours coming from the oxidation ponds over the coming weeks.

“We’re pleased that the aerators are now operational. The quality of the effluent being pumped into the ponds should improve, leading to a gradual improvement in the biological health of the ponds,” Ms Beaumont says.

At the same time, planning work is under way to address the less frequent – but more acute – unpleasant smells that are coming from the 26,000m3 of filter material inside the destroyed tricking filters. 

“When it rains and the filter media gets wet, the organic matter trapped within the filter media begins to rot and it releases high levels of unpleasant odours until it dries,” Ms Beaumont says. 

“Our focus is to remove the filter media as soon as possible to eliminate the odour source. Following damage investigations and discussions with our insurer, we will look to appoint a contractor for this work this month.

“The actual start date of media removal, and the time required to complete the work, will be determined after we appoint a contractor and their methodology has been confirmed.”

Further information and updates on the Christchurch wastewater treatment plant’s continued recovery from the 1 November fire can be found at ccc.govt.nz/wastewaterfire.