Christchurch Wastewater Treatment Plant update

Monday 9 February 

The latest

We’re continuing to closely monitor the health of the ponds, with daily checks. Today, we can report that the health of the ponds is continuing to recover, but dissolved oxygen levels remain at lower than ideal, which means there is a risk of increased odour.

A new aerator for Pond 2B is being installed and tested today, and we’re hoping to have this up and running tomorrow. When the aerator is switched on, it will temporarily disturb the sludge, which may produce a localised, short‑term odour lasting 1–3 hours. We’ll be using our odour monitoring equipment to assess how much odour is being generated and respond accordingly to minimise odours.

Our community odour monitoring sites are being updated more frequently, and we’re monitoring the weather, with rain expected later in the week. We’ve sent an algae sample to a specialist lab, which has confirmed that the species appearing in high numbers is consistent with ponds under heavy load. Our team is now working with experts to put together a plan that will help make the ponds more resilient in the future. 

What happens next

About 32 Council staff from across the organisation will be calling on the immediate neighbours of the Wastewater Treatment Plant (around 750 homes) tomorrow (Tuesday) to hear the community’s priorities. If they’re not home, we’ll leave contact information so they can get in touch.

The information will be collated and provide valuable insight into the possible options for community support. Any decisions would need to be made by the elected Council.

Latest hydrogen sulphide monitoring

We've increased hydrogen sulphide monitoring to twice weekly. See the latest results below. The biological health of the ponds is fragile. Hydrogen sulphide has been detected at all five community monitoring sites. Our teams are doing everything they can to address the current situation. 

An update to our odour status map

Please note that we've upgraded the status of the Plant and Pond 2B from orange (Possible) to red (High). You can always see the latest status, including when it was last updated, on our website. 

Health, wellbeing and support services 

We’re sorry for the impact this continues to have on you and your whānau. Please be assured we are doing everything we can to support the system’s recovery and reduce odour where possible.

Here's the latest advice from Dr Imogen Evans, Public Health Medical Specialist for the National Public Health Service:

"Exposure to hydrogen sulphide stench 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 stench don't experience physical health effects, continued exposure to unpleasant or nasty, noxious stench 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 stench 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.