Work progressing toward new wastewater treatment plant

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8/11/2013 12:00:00 a.m.

8 November 2013

Mayor Annette Main says work is under way in preparation for building the district’s new wastewater treatment plant.

“As well as cleaning up our environment, we are building a fully functioning, compliant wastewater treatment plant that uses a robust and proven process,” Mayor Main said.

The project involves a number of stages:

  • Removal of sludge from the settling pond.
  • Removal of sludge from the main pond.
  • Building a lined earthen wall in the main pond to create a separate covered anaerobic section.
  • Installation of contact stabilisers and clarifiers.
  • Upgrading the ultraviolet disinfection process.

“During the last four weeks we have been reducing the level of sludge in the settling pond and, as we have previously advised, this work will cause odours,” Mayor Main said.

“While the odour is a major issue for us all, we are on the way to having a fully functioning treatment plant.

“There is still about two metres of sludge to be transferred from the settling pond into the main pond and this week we have been able to start removing the sludge at the required high rate. Four new, bigger pumps have been installed and on Thursday we started using one of these which caused the smell to increase as more sludge was transferred. As the rest of the pumps are brought into action this week, the smell will increase further. It is expected to take another three weeks to clear the settling pond, but that depends on the weather.

“At this stage, the MetService’s 10-day forecast for our district is for hot, dry weather with southerly winds so we can expect strong odours during that period.

“People need to be aware that odours will continue, and will increase over the summer period as the load into the treatment plant increases and as we work on the main pond. There will be a break in work during the Christmas period but the length of that break will depend on progress with the sludge removal.

“We have increased the odour mitigation dosing but this will only reduce the smell, not eliminate it. Our experts advise that without the odour fence, the smell would be much worse.

“The community should also be aware that although bypassing the treatment plant and discharging wastewater directly to sea could be an option if the smells reach the level they did last summer, this would have an impact on residents and visitors who want to enjoy our beaches for recreation, such as swimming, surfing and fishing, during the summer period as well as having an adverse effect on the environment.

“We’re in for some more strong odours in the coming days, weeks and months – it will be unpleasant but we must try to focus on the end result. Once construction of the upgraded plant begins about Easter next year, there will be no more odours as in future the sludge will be stored in a covered pond and regularly removed.”

Page reviewed: 08 Nov 2013 12:00am