Bacteria back in business

Published: 6 July 2023

Work to bring Napier’s Wastewater Treatment Plant back to pre-cyclone operational condition is well under way and progressing on schedule with the first biological trickling filter (BTF) now up and running.

Flooding from Cyclone Gabrielle resulted in most of the treatment plant’s equipment being significantly damaged. Since April, the site has been treating wastewater using its miliscreen process rather than the full operation, which includes two biological trickling filters commissioned in 2014.

Russell Bond, Napier City Council’s Executive Director of Infrastructure, explains that the Wastewater Treatment Plant can operate just using its miliscreens but the biological trickling filters add another layer of treatment and getting them up and running has been a priority.

“Bringing the BTFs back online has been a major focus and there’s a big team dedicated to making it happen,” says Russell. “It’s rewarding to see one of them commissioned and put into operation again.”

Now the BTF is operating, it will take a few weeks for the bacteria inside the filter to regrow to its pre-cyclone levels. The second biological trickling filter is currently being rectified and will soon undergo commissioning. It is scheduled to come online by mid-August. The plant can operate with just one BTF during normal flows but having two in operation is needed for full treatment during major wet weather events.

Odour beds that were also damaged during the cyclone have been cleared and repaired and will soon receive new bark to ensure they can work in tandem with the BTFs.

Other current work at the Wastewater Treatment Plant includes completion of the Power Distribution Centre refurbishment and ongoing silt removal.

For more information visit the Recommissioning Napier’s Wastewater Treatment Plant webpage here.

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