Thursday 4 June

Christchurch Wastewater Treatment Plant update

Construction update: activated sludge reactor

It may have seemed a little quieter on site this week, and that was intentional. We took the opportunity to carry out maintenance on the larger rigs while also completing a series of specialised ground tests.

These tests involve sending seismic waves through the ground at recently established boreholes across the site. The testing requires minimal vibration, so our normal piling activity was paused. The testing assesses whether the ground works meet design requirements.

A further round of this testing will take place at the end of the stone column installation. This will confirm whether the ground has been sufficiently strengthened. Installation of the stone columns will now continue as normal, with a target to complete this work by mid-July.

All about the pipes

Here's a rundown of everything involved in laying the 380 metres of pipes needed to get the activated sludge plant up and running. Laying each section requires a detailed, multi-step process. Pipes are installed in segments of around 30 metres at a time.

Each section involves:

• Excavation and support – A trench is excavated and sheet piles are installed where needed to stabilise the sides.
• Concrete base – A concrete foundation is poured to provide a stable bed for the pipes.
• Pipe placement – Pipes are welded together, lifted into position, carefully aligned, and secured.
• Framing – Temporary framing is built around the pipe section.
• Concrete pour – Concrete is poured in two stages to encase and protect the pipes.
• Finishing work – Framing is removed and the trench is backfilled to ground level.
• And repeat – Then it's time to repeat the process for the next section. We'll do this approximately 13 times in total.

While it may not always look fast from the outside, each step is critical to ensuring the durability and reliability of the system for years to come.

Latest timelapse video 

Check out our latest timelapse video showing all the construction activity that happened on site in May. 

Aerator installation work update 

Work to install the new aerators across Ponds 2a and 2b is progressing well, with steady activity continuing across the site to prepare for the aerators going on the ponds. A lot of work is also happening to ensure the necessary power supply is in place to support the new equipment.

We’re also just a couple of weeks away from completing the new pond flow-splitting structure, which will balance the flow between the three aerated ponds. This is an important milestone, as it will allow us to better control how wastewater moves through the system and make the most effective use of the new aerators once they are fully operational.

Opportunities to connect 

Join us at a community meeting 

We’re hosting a community meeting on 17 June to provide an update on the activated sludge reactor construction and aerator installation works.

6pm–7.30pm, Wednesday 17 June 
He Waka Tapu, 161 Pages Road

At the meeting we'll give updates on: 

• Activated sludge plant construction – construction is charging ahead on site. Get an update from the Council's project manager. 
• Aerator installation – The first set of the new aerators is being commissioned the week of this meeting. Come along and hear an update on what we've completed so far, and the work still to come. 

We'll also have our operations manager and community liaison on hand to answer questions. 

There is no need to RSVP – just show up on the day.  

Tune in to Monday's Community Board update 

At 4pm this Monday 8 June our staff will provide their regular project report at the the Waitai Coastal‑Burwood‑Linwood Community Board 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.

Drop-in sessions at Bromley Community Centre wrapped up 

The community-led drop-in sessions at the Bromley Community Centre wrapped up today. Our community liaison Gary Watson has been attending these sessions and appreciates everyone who took the time to come along and have a chat.

Gary remains available to connect with anyone who has questions or would like to discuss the project. Please feel free to reach out to him directly via email. 

Pond health, odour and what to expect this weekend

Pond conditions remain stable, although the water is currently greener than usual at this time of year due to algae growth. The extended spell of warm, dry weather has led to algae persisting for longer than typically seen.

Our team is closely monitoring the situation and continuing regular checks. At this stage, we do not anticipate any significant increase in odour levels in the short-term. The pond tracker remains the same. 

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.