28 June - Ponds remain in settled 'winter mode'
Oxidation ponds remain in settled 'winter mode'
All of the five disc aerators on Pond 1 have been repaired and reinstalled, and have operated consistently since the commissioning started on 19 June. The four-week commissioning will test the performance of the aerators, but there haven't been any notable issues to date.
Site-based staff have purchased a hand-held hydrogen sulphide monitor so they can keep track of H2S levels around the plant and ponds. This testing enables us to be very responsive to any environmental changes at the facility. We're undertaking this testing regularly, and no notable results have been detected.
Site-based staff are also undertaking a trial partial opening of one of the control gates between Pond 2A and 2B. This has introduced a new, minor flow path across Pond 2A, making better use of the full area of the pond. Site staff are routinely monitoring the pond with a marginal increase in dissolved oxygen recorded.
We're also undertaking a trial on the temporary activated sludge plant; we've brought one of the two spare secondary contact lanes back into service, and we'll monitor and assess the performance over the coming weeks.
The contractor will undertake a sludge survey of ponds 1,2A and 2B from Monday 3 July. This will be weather dependent, e.g. windy weather can stop work due to health and safety risks.
We update the webpage below with the latest updates as they come to hand.
After this e-newsletter, we will now only send out new newsletters as required, if the situation changes or if there is new information to share.
Latest hydrogen sulphide monitor results
We have strategically set up hydrogen sulphide (H2S) monitors at locations around the oxidation ponds and nearby community. These have been in place since July last year and the results are published on the webpage below.
Since the five disc aerators have been repaired, levels of H2S have remained low, intermittent, and well below the guideline of 0.03ppm.
Today we've also reinstalled a permanent meter at the Shortland St site, which will help give us better coverage of all wind directions. Results from this site will be published online next week.
Where to get help
If 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 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
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.
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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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