We’re doing our best to operate the treatment plant in its damaged state, and are continuously making minor changes to improve its performance and keep odours to a minimum.

Our monitoring shows that in certain wind conditions the odour comes from the plant itself, rather than the ponds, and we’re looking at ways we can reduce this.

The oxidation ponds have been operating reasonably well, with H2S levels now at .01ppm. However, during the holiday period the volume and composition of sewage being received at the plant varies significantly and at times the activated sludge plant struggles to adapt, which can lead to occasional odours.

Our contractor is working hard to get two oxidation pond aerators back into service after mechanical breakdowns last year. The contractor is also working through the annual maintenance for all the pond aerators to ensure that they are all available and serviced for the winter period.

We’re making it a priority to explore a permanent solution. For those who might have missed it, an update report on the Christchurch Wastewater Treatment Plant’s insurance claim was provided to councillors in November 2023 – you can find more information and read the report here.

Hydrogen sulphide monitor results

The summary graph for the past three weeks shows that H2S is being detected in the Shortland Street area, and this is occurring at times when the wind is coming from the treatment plant itself rather than the direction of the ponds.

H2S detected at the Dog Shelter may be coming from Pond 4 at times. At this time of the year rotting sea lettuce on the shore of the estuary at low tide can also generate H2S. This is likely to be the cause of some low levels detected in the South Brighton area.

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.