The Christchurch City Council has received a formal warning from Environment Canterbury due to persistent foul odours emanating from the city’s Wastewater Treatment Plant.
Residents, like Kelly Gibson, have expressed their distress in a email saying “morning after morning we are woken by the terrible stench, at 3AM, it starts ramping up! Have you all taken a look at the graph for Shortland Street recently and the unexceptional high readings on it??
“Are you concerned at this information? Enough is enough – I am sick of hearing our team is working on it, I and the rest of the community want answers! This is not fair to be woken every morning with a headache and feeling like you are going to vomit while eating your breakfast.”
In response to the situation, Environment Canterbury issued a “Overall Inspection Compliance: Significant non-compliance letter” to the council on February 19th.
The letter highlighted, “this condition is graded as significant non-compliant, as an offensive and objectional odour has been substantiated on multiple occasions beyond the property boundary.
A total of approximately 162 odour complaints were received between the monitoring period, 1 November 2023 – 31 January 2024.
From the total incidents reported above, there were three occasions where the odour was substantiated.
This matter needs your immediate attention. Failure to address this matter may result in enforcement action being taken.”
Acknowledging the community’s concerns, the Christchurch City Council detailed their ongoing efforts to mitigate the odour issue.
“Our staff continue to address the recent increase in odour through a number of actions.
“The primary settlement tanks at the plant were previously identified as one of the main contributors of odour.
“To address this, we’ve now reduced the number of tanks in service from seven to five. As a result, sewage is now spending less time in the tanks before it moves to the next stage of the treatment process.
“Early indications show this has reduced the odour from this source, and we’re planning on taking another tank out of service next week to improve things further.
“Our external odour-specialist consultant is making good progress with their intensive odour monitoring programme and they’ve made a small number of recommendations for us to implement.
“The trial at the temporary activated sludge plant is underway and being closely monitored to see if the addition of another aeration lane improves the performance of the temporary plant. It will take more time for us to assess if this has any benefits.
“The oxidation ponds continue to operate well. Pond #1 now has all 16 aerators back in service. At some stage next week maintenance work requires us to briefly turn off all 16 aerators. We expect they’ll only need to be off for a couple of hours and we’ll plan this for a time where wind conditions are favourable for maintaining the aeration of the ponds without assistance.”
