Information about our ponds' health tracker 

With the new activated sludge system is operational, we're tracking the health of the oxidation ponds as the better-quality wastewater begins to flow through them.

Over the coming weeks we expect the health of the ponds to improve, and the odour levels to drop, and we'll reflect this in our weekly updates on the status of the ponds.

As the water quality improves (lower organic load and presence of dissolved oxygen levels) we'll turn a pond from 'red' to 'orange'. We're still on track for this to occur by mid-September and for the odours to gradually reduce over the coming weeks.

However, it will take another couple of months for the biological health of the ponds to return to a level of resilience where they’re capable of handling increased organic loads if there’s a temporary failure somewhere in the treatment plant process.

We intend to only turn a pond 'green' when there are higher levels of dissolved oxygen present and its biological health reaches this level of resilience.

Weather conditions leading to increased odour reports

Due to milder conditions and a gentle easterly wind over the past few days, Christchurch City Council has received an increased number of reports of unpleasant odours coming from the oxidation ponds at the wastewater treatment plant this week.

While the very high rainfall in July flushed the ponds and the westerly winds over the past few weeks have given many Christchurch residents a reprieve from the smells, the biological health of the ponds is still poor.

The graph above shows that residents near our Shortland St site experienced increased levels of hydrogen sulphide between Monday 15 August and Wednesday 17 August.

However, the levels dissipated quickly by the time they reached our other western sites at Rudds Rd and Bromley School .

Updated air quality testing results

We’ve uploaded last week's data for the six continuous air monitors that have been set up near the Christchurch Wastewater Treatment plant.

The monitors are to detect the levels of hydrogen sulphide in the Shortland Street, Maces Road, Estuary Road South, Rudds Road areas, as well as at Bromley and South Brighton Schools.

Note the readings online are only up until Friday 12 August - we'll publish graphs showing this week's increased levels of hydrogen sulphide early next week once the data from all of the sites has been collated.

You can read the data for all six locations, and an explanation about how to read the information by clicking the link below. You can also find past readings for each site.

Stay updated

We want everyone to be able to stay updated on our response and recovery from the treatment plant fire, and we regularly post new information and reports on ccc.govt.nz/wastewaterfire 

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 in advance for your patience and understanding as we continue to work on minimising the unpleasant smells after the fire. We’ll be in touch again soon.