Thursday 25 June

Christchurch Wastewater Treatment Plant update

Aerators operating well 

The newly installed aerators are proving beneficial so far. No odour was noted when they were first commissioned, and dissolved oxygen levels at the downstream end of the ponds are higher than anticipated, which is a positive result. We're continuing to monitor performance closely.

Flow split structure in place

We’ve also put in a flow split structure to help us control the movement of wastewater through the ponds. This was implemented on Tuesday, and initial water levels were different than we expected.

We knew some adjustment might be needed as this is the first time the ponds have operated in this way. The team has a good understanding of the changes required and will continue making minor adjustments over the next couple of weeks to fine-tune the system. We do not expect this work to adversely affect pond health or increase odour risk.

The photo below shows the new split structure. 

Activated sludge reactor progress update 

We’re still making great progress on site, with stone column installation now nearing completion. We've now installed 1370 of 1600 total stone columns and by the time this stage of the project is finished we'll have installed an impressive 22 kilometres of stone columns – enough to stretch from Bromley to Woodend.

Pipe installation works are also advancing well, with excavation underway on a new trench extending from the previously installed pipeline towards the new plant. We’ve slightly changed our schedule to prioritise completing this section first.

The excellent progress made on the stone column installation means we can move onto the next stage of works. Once the pipe installation is complete, the team will be well positioned to begin installing the load transfer platform as planned.

We’re grateful to our contractors and everyone working on the project for maintaining momentum and helping keep this critical piece of infrastructure moving forward.

Odour and your health 

We recently recorded a video with Medical Officer of Health Dr Cheryl Brunton. She answers common questions about the odour from the Christchurch Wastewater Treatment Plant’s oxidation ponds and health.

Reminder: you can watch our recent community meeting online

We held a community meeting on Wednesday 17 June. You can watch the presentations from the meeting on the Waitai Coastal-Burwood-Linwood Community Board YouTube channel.

Pond health, odour and what to expect this weekend

Algae levels continue to reduce as expected as we move further into winter operating mode. Based on current conditions, we do not expect the forecast rain or colder weather to create an odour issue. The remainder of the plant continues to perform reasonably well.

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.