Trickling filter demolition time-lapse 

Check out the time-lapse video showing the trickling filter demolition from start to finish. The demolition started in November 2024 and was complete in March 2025.

The site is now ready for construction of the Activated Sludge Reactor. While the site will be quiet for a few months, there is plenty going on behind the scenes. Our team is busy finalising the design for the reactor. We’re also working towards selecting a contractor and awarding a contract.

You can see a design and construction timeline on our website. 

Pond health update 

The oxidation ponds continue their transition into winter mode, with the midge numbers and algae concentration dropping off. While pond health has dropped, dissolved oxygen levels are stable. This means the anoxic conditions which can generate increased odours aren’t present at this time. 

The temporary activated sludge plant is delivering good results and performing well after its temporary reduction in capacity over March (back in service 28 March). This has reduced the loading to the ponds and they are responding reasonably well.

We're continuing to monitor the ponds closely, but are pleased with the way the results are going, and we are not expecting any significant changes or odour events to occur as we fully transition into winter mode.

As always, intermittent odours are still possible in certain weather conditions including settled weather and high rainfall events. 

The new disc aerator installed at the front of Oxidation Pond 1 continues to work very well. It directs the incoming flow to the larger vertical shaft aerators. This helps boost the dissolved oxygen levels in the pond. 

The contractor has finished repairs on two disc aerators which have been down over the past couple of weeks and we expect to be going into Easter  with all 16 aerators operational. 

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.