Update on addressing odour and the insurance process 

An update report regarding the insurance process for the Christchurch Wastewater Treatment Plant was received by Council at the Finance and Performance Committee meeting on Wednesday 28 February.

The report contains all the information that can be released at this stage to keep the public informed without prejudicing our ongoing insurance claim or disclosing confidential commercial arrangements. The report confirms that design work to restore the trickling filters is underway and progressing well. Design work is due to be complete within the next two months.

At the meeting the Council acknowledged the community is continuing to experience odours from the Wastewater Treatment Plant. Our staff are addressing 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 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 this 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.

Hydrogen sulphide monitor results

The graph for this week shows that H2S is being detected in the Shortland Street area, and this occurs at times when the wind is coming from the treatment plant itself rather than the direction of the ponds. This is particularly so when wind conditions are light.

Our staff continue to do all they can to reduce the odour as quickly as possible and are making changes to processes at the plant. 

There are no readings for the dog shelter as that meter is being used at another site.

Detections at the South New Brighton School might be from decomposing sea lettuce in the estuary. We're continuing monitoring in this area to investigate this.

Where to get help

If you need health support, we have information available on our website. This includes information on Pegasus Health's Partnership Community Workers and contact numbers for Healthline and counselling services.

Stay updated

We want everyone to be able to stay updated on our response and recovery from the treatment plant fire, and we regularly post new information and reports on ccc.govt.nz/wastewaterfire 

You're welcome to send this update to your networks. If you know someone in the community who doesn’t have email or internet access, please print this newsletter off and pass it to them.

If you know of anyone who would like to receive this e-newsletter they can subscribe online. 

If you have any questions, or would like further information on the project, please call us on 03 941 8999 or 0800 800 169 or email wastewater@ccc.govt.nz  

Thanks for your patience and understanding. We’ll be in touch again soon.