Thursday 6 August
Christchurch Wastewater Treatment Plant update
A chilly week on site
Winter has certainly made its presence felt on site this week, with snow covering the ground on Tuesday and a number of the construction team sidelined by seasonal illnesses. Despite these challenges, work continues to progress steadily on the project.
We're currently focused on installing the pipework and constructing the load transfer platform. We're pleased to report that the vibration generated by the roller compactor has been less noticeable than we originally anticipated. While this is encouraging, the team will continue to closely monitor vibration levels as work progresses over the coming weeks.
We're also in the early stages of planning another community information session for September to share details of upcoming works and provide an opportunity for residents to hear more about the next stages of the project.
Thank you to the community for your ongoing patience and support as construction continues.
Clarifier repairs starting in September
We're getting prepared to start a major overhaul of Clarifier 4 in September to ensure the wastewater treatment plant continues to operate reliably and efficiently.
Clarifiers play an important role in the treatment process. They use gravity to separate solids and suspended particles from wastewater, producing cleaner water that then flows to the ponds for final treatment before discharge.
The drive mechanism that powers Clarifier 4's rotating arms has reached the end of its service life and requires replacement. Rather than replacing individual components, we're carrying out a full overhaul to improve reliability and reduce the risk of future issues. We'll undertake a similar overhaul of Clarifier 3 in 2027.
Low risk of odour during this work
To carry out this work, Clarifier 4 will need to be emptied and temporarily taken out of service for around eight weeks.
While this may slightly reduce the treatment plant's capacity during this time, the risk of increased odour is expected to be low. This is because the new aerators in Ponds 2A and 2B will be operating, along with changes to how wastewater flows through the ponds. Together, these improvements will help maintain treatment performance and minimise the potential for odour.
We've also deliberately scheduled this work for September, when the new electrical connection to the aerators is expected to be completed, to further reduce the likelihood of any odour impacts while Clarifier 4 is out of service.
Next steps
Our team has already installed cutoff walls that make it possible to isolate the treatment plant's clarifiers. This was a key preparatory step for the repair works.
This month we'll be installing the equipment needed for dewatering ahead of work starting in earnest in September.
We'll provide further updates via this newsletter as the project progresses.
A word from Gary
It’s great to see the positive progress being made on the wastewater treatment plant rebuild. I’ve been very impressed with how the project is tracking so far and would like to sincerely thank our immediate neighbours for their patience and understanding while this important work continues.
Over the coming weeks, we’ll be focusing on work along the fence lines, including tree trimming. We’ve also begun initial engagement with nearby residents about the proposed new bunding along the fenceline, and we appreciate the constructive conversations and feedback we’ve received to date.
I’ll be manning the barbecue at the opening of the new bike pump track in Bromley Park this Saturday from 10am to 1pm. If you’re planning to come along, please feel free to stop by and have a chat.
As always, if you have any questions about the rebuild or would like to discuss any aspect of the project, please don’t hesitate to get in touch by emailing me at gary.watson@ccc.govt.nz or calling/texting 027 239 6317.
Tune in to Monday's Community Board update
On Monday 10 August our staff will provide their regular project report at the the Waitai Coastal‑Burwood‑Linwood Community Board meeting. The meeting starts at 2pm and the wastewater treatment plant update is scheduled for later in the meeting.
This session is an information update only. It’s an opportunity to keep the Board and community informed about the work that's underway.
The briefing will be livestreamed here, and a recording will be available after 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
Pond health, odour and what to expect this weekend
We're thrilled to see positive improvements across all the ponds following the pond flow balancing last week. Pond 1 has started to show positive and consistent improvements after lagging behind in recent monitoring.
The ponds are very well settled in winter mode, and we're now taking the opportunity to prepare for the coming winter to summer transition.
One of the vertical shaft aerators on Pond 1 has been out of action and our contrator is working on a repair. The rest of the aerators had proactive planned maintenance inspections yesterday
The new aeratros on Ponds 2A and 2B have been operating consistently on diesel supporting the improved performnce across the ponds.
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.
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