Queenstown Lakes District Council property and infrastructure general manager Tony Avery said the situation was unfortunate. Photo: RNZ / Marika Khabazi
Otago Regional Council is investigating a series of failures at Wanaka's wastewater treatment plant.
Queenstown Lakes District Council says heavy rain hit last month while the Project Pure Wastewater Treatment Plant was operating at reduced capacity due to a major upgrade, leading to a spike in nitrogen levels and treated wastewater to flood disposal fields and run off.
The district council's property and infrastructure general manager Tony Avery said the situation was unfortunate and would be unwelcome to many.
"There was always a risk that some parts of the facility's treatment process would be negatively impacted while carrying out these significant upgrades. To reduce as much risk as possible, works were carefully planned to take place during low flow periods and operational teams implemented several mitigation strategies," he said.
Queenstown Lakes District Council acknowledged the compliance issues in a media release on Tuesday.
It comes after recent compliance problems at the district council's Hāwea and [https://www.rnz.co.nz/news/national/563664/queenstown-lakes-district-council-must-fix-issues-with-shotover-wastewater-plant-court
Queenstown treatment plants].
Mayor John Glover said he wanted to share the information proactively with the public.
"As governors, we will need to review what has happened to fully understand why and especially in the context of regulatory compliance failures at Shotover and Hāwea treatment plants," he said.
Avery said while the issues at the Shotover plant also related to the disposal field, the system at Project Pure was different.
The council did not expect any long-term issues, he said.
"Project Pure's fields have been operating successfully for approximately 15 years now, have more modest loading rates and discharge through free-draining soils well above groundwater," he said.
Upgrade work was now complete and the plant's performance was improving, the council said.
Queenstown Lakes District Council said it referred the performance issues to the regional council immediately and expected to receive its investigation findings shortly.
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