Christchurch Wastewater Treatment Plant update

Tuesday 17 March

The latest on the ponds

The wastewater treatment plant is performing reasonably well under the circumstances, and pond conditions have continued to improve. Algae numbers and dissolved oxygen levels are improving, supported by the recent run of settled, sunny weather.

We are still cautious heading into the transition to winter, especially given how challenging summer has been for the pond system. The change in season can create fluctuations in oxygen and biological activity, which in turn can cause spikes in odour.

Overall, we are seeing slow and steady improvement, and things are notably more stable than they were a month ago. While spikes in odour remain possible – particularly overnight or during calm conditions – the general trend has been positive.

The latest pond odour tracker update is now live, with pond 2b moving from red to orange and pond 3 moving from orange to green, reflecting the positive changes in the pond system. 

Response to the abatement notice

We submitted our response to Environment Canterbury’s abatement notice yesterday.

The full response includes several documents and components, but the key element relating to odour improvement is a report staff are currently working on, which will go to Council in early April. This report outlines a range of options to reduce odour including:

• Increasing aeration on the oxidation ponds.
• Creating a diversion pipeline to send a portion of treated wastewater directly to the ocean outfall.
• A combination of both increased aeration and a diversion pipeline. 

Another part of the response is an updated Odour Mitigation Plan, which is available now on our website.

Once the Council decides what option to proceed with, we’ll be able to provide more certainty around timeframes, costs, and next steps. In the meantime, work is progressing so that we can move quickly once a decision is made.

Watch the community board update 

Our Three Waters Manager, Adam Twose, provided an update to the Waitai Coastal‑Burwood-Linwood Community Board last night. This included an outline of how a diversion pipeline could operate.

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.