Christchurch Wastewater Treatment Plant update

Friday 13 March 

Sunny conditions support pond health 

Pond conditions have remained stable over the past week, with a slow, steady trend of improvement. Odour levels have generally been low during the day, with some increases overnight when still conditions allow odour to settle and linger.

The recent stretch of sunny weather is helping support pond performance. These brighter conditions are favourable for algae activity, which plays an important role in maintaining oxygen levels across the ponds.

We still believe the ponds are transitioning into their winter‑mode pattern as the temperatures cool. This is when the algae and biological activity in the ponds can become imbalanced, and lead to temporary increases in odour. 

Ocean outfall and mitigation options 

Our team is continuing detailed technical work on options to improve pond health. 

As we've mentioned previously, one of these options is diverting a proportion of treated wastewater around the ponds and directly to the ocean outfall.

Alongside the outfall option, the team is also looking into  aeration at the ponds to boost treatment capacity and overall system performance.

Both of these options are in the planning stage, and no decisions have been made. Before any direction is confirmed, a proposal will go to councillors for consideration and a formal decision.

What to expect over the weekend

With settled conditions at times and the ongoing seasonal transition, intermittent odour remains possible – especially overnight or early in the morning when calmer air allows odour to hang around. During the day, the mild and sunny conditions should continue to support pond stability.

We’ll continue daily management actions and close monitoring through the weekend to respond quickly to any changes.

Tune in to Monday's Community Board update 

At 4.30pm on Monday, Wastewater Treatment Plant Operations Manager Adam Twose will brief the Waitai Coastal‑Burwood‑Linwood Community Board on the option to divert a proportion of treated wastewater directly to the ocean outfall. 

This session is an information update only. No decisions will be made – it’s simply an opportunity to keep the Board and community informed about how it could work and the work underway.

The briefing will be uploaded to the Waitai Community Board YouTube page immediately following the meeting. If you’d like to attend in person, the meeting will be held at the Waitai Community Board room on the corner of Union and Beresford streets.

A word from Gary Watson 

I’m looking forward to spending more time out in the community over the next couple of weeks, reconnecting and continuing the conversation. I’ll also be at the board briefing on Monday afternoon.

If you’d like to catch up or chat through anything, feel free to get in touch anytime at Gary.Watson@ccc.govt.nz.

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.