Christchurch Wastewater Treatment Plant update31 May 2024 Oxidation pond biology transition near completionFor the past week we've been closely monitoring the oxidation ponds as they finally make the transition from summer to winter mode. Last year an increase in odour from the ponds occurred during this period, but this year staff implemented a plan to temporarily alter the flow paths through the ponds to try and reduce odour based on experience and knowledge gained last year. This year’s transition has come nearly a full month later than last year (late May as opposed to late April). As expected, we have seen algae levels reduce and the biology in the ponds slow down as the temperature has dropped. We've now completed work to change the flows through the ponds for winter, meaning they're now ideally set up for the coming cooler months. We're continuing to undertake odour monitoring, and anticipate that current odour levels will continue to drop once the full summer to winter transition of the ponds is complete. All the treatment processes at the wastewater treatment plant continue to work as well as can be expected, and the temporary activated sludge treatment plant process is also operating well. The weather forecast for the coming week is mixed, but with predominantly cooler temperatures and the possibility of the odd windy day, which may help disperse odours. We recognize the ongoing stress caused by the odours and are working hard to reduce them where possible. Maintaining operations at the damaged plant can be tough, but our team is diligently working to adapt and respond promptly. There are currently 15 out of the 16 aerators currently in service. One repaired aerator has been returned to service and another is now undergoing repairs. We've almost completed the planting of 45,000 plants, with the last few thousand due to go into the ground over the next couple of weeks. Insurance update: trickling filter concept design completeAn update report regarding the insurance process for the Christchurch Wastewater Treatment Plant was provided to councillors this week at the Finance and Performance Committee meeting. The report and presentation contain all the information that can be released at this stage to keep the public informed without prejudicing our ongoing insurance claim or disclosing confidential commercial arrangements. The report confirms that the concept design for the restoration of the trickling filters is now complete. The design is to restore the trickling filters to their pre-fire state, but with some changes to allow for current best practice, modern equipment and safety standards. Example in the photo below: The concept design also explores opportunities for operational improvements to the trickling filters that are outside the Council’s insurance policy entitlement. Some opportunities have been identified such as improving access to the trickling filters for maintenance, additional hardstand areas for maintenance purposes, and electrical, instrumentation and control improvements. These potential improvements will be considered further as part of the detailed design. There has not been any decision to commit to these improvements, and they will be brought to the Council for consideration following completion of the detailed design. The estimated costs of these improvements have been allowed for in the Draft Long Term Plan 2024–2034. The Council has sufficient insurance to cover the costs of restoring the trickling filters and further insurance to cover the additional costs of operating the Plant. The Council continues to work productively with its insurers to resolve the claim. The insurance claim has not affected progress on the restoration of the trickling filters. Hydrogen sulphide monitor resultsWe are continuing to monitor levels of hydrogen sulphide at residential locations around the wastewater treatment plant. Monitoring results have shown that levels over the past month have been decreasing and are now well below the health guideline of 0.03ppm. At times light winds still carry hydrogen sulphide, and other odours, to nearby residential areas but the levels are below 0.01pmm. Where to get helpIf you need health support, we have information available on our website. This includes information on Pegasus Health's Partnership Community Workers and contact numbers for Healthline and counselling services. Stay updatedWe 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 for your patience and understanding. We’ll be in touch again soon. You received this email because you are subscribed to updates from Christchurch City Council. |