Christchurch Wastewater Treatment Plant update

Tuesday 3 February 

Ponds showing signs of improvement

Our latest monitoring suggests signs of improvement. The pond system is looking healthier today, and we’re optimistic that things are moving in the right direction.

Overnight we adjusted pond flows in anticipation of the predicted rain, and we’ll continue making operational changes as needed to manage the weather conditions and support the recovery of the ponds. 

Our early investigations indicate that the stench is likely the result of a combination of weather factors and wastewater loads into the ponds. Right now our focus is firmly on restoring the health of the pond system. Once things have stabilised, we’ll undertake more detailed investigations to confirm the root cause.

Long-term solution 

Once commissioned, the new activated sludge reactor will address the long‑standing odour issues that followed the fire. We're actively looking for opportunities to accelerate this programme wherever possible, though the timeline is already extremely tight. We’ll continue to make the most of any chance to bring that work forward.

Our contrators are already busy getting construction started and the programme is expected to take about three years, with commissioning targeted for 2028. 

We know this is a long time to wait, and while we construct the new plant we're doing everything we can to keep the fire-damaged plant and oxidation ponds operating as well as they can. 

Reminder – Residents meeting tonight 

Get an update on the stench, and what we're doing over the coming weeks to address odour.

We’ll have Council staff on hand to answer your questions.

Time: 5.30pm to 6.30pm

Date: Tuesday 3 February

Location: Bromley Community Centre, 45 Bromley Road

If you can't make the meeting, you'll be able to view it online the next day.

Odour status map now live 

This morning, we introduced an expanded traffic light system that shows the likelihood of odour across the different parts of the wastewater treatment process. 

The plant itself and each of the seven oxidation ponds have their own traffic light.

The map shows which areas of the overall system are currently more likely to produce stench, and will be updated whenever our staff become aware of a change in conditions. 

Health, wellbeing and support services 

Dr Annabel Begg, Medical Officer of Health for the National Public Health Service has provided the advice below:

"Exposure to hydrogen sulphide odour arising from the Christchurch wastewater treatment plant can cause nausea, headaches, eye and throat irritation, skin irritation, sleep disturbance, and worsening asthma symptoms at relatively low concentrations.

"If people exposed to the odour don't experience physical health effects, continued exposure to unpleasant or nasty, noxious odours can still have an adverse effect on people's mental wellbeing.

"While exposure to hydrogen sulphide is unpleasant and may result in health effects, it doesn’t accumulate in the body. Any health effects would be expected to resolve when the odours are brought back to normal levels, and long-term health effects are highly unlikely.

"People experiencing health issues as a result of the odour coming from the treatment plant should seek health advice from their GP, doctor, Hauora or healthcare provider, or call Healthline free on 0800 611 116, anytime 24/7 for advice as soon as possible. In an emergency call 111."

There are also free services across Ōtautahi Christchurch available to support and enhance overall health and wellbeing. These include:

Health Improvement Practitioners (HIPs)

HIPs are qualified mental health professionals based in General Practices (GPs). They offer free, 15–30 minute sessions focused on practical strategies to support mental and physical wellbeing. There is no limit to the number of sessions you can access.

You can book directly through your GP.

Pae Ora ki Waitaha Support

Pae Ora ki Waitaha is a free healthy lifestyles service developed with Māori and Pasifika providers.

More information is available on their website. 

Healthline

Healthline is a free over-the-phone health service available 24 hours a day, seven days a week. If you or someone in your family is unwell, you can call Healthline and speak to experienced nurses and paramedics for health advice and information about what to do next.  

Call 0800 611 116.

Stay updated

We want everyone to be able to stay updated on what's happening at the Christchurch Wastewater Treatment Plant, and we regularly post new information 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.