Shotover Wastewater Treatment Plant in Queenstown. Photo: Supplied / Queenstown Lakes District Council
A new problem has emerged at Queenstown's Shotover wastewater treatment plant, leaving a lingering bad smell.
Earlier this month, urgent repairs were carried out to fix an issue with the plant's sludge processing and dewatering system, which also caused a waft of odour over the Frankton area.
The Queenstown Lakes District Council (QLDC) said there was now a problem with the aeration grids, which was affecting the biological treatment process.
QLDC property and infrastructure general manager Tony Avery said the council was aware odour continued to be a noticeable problem in the area.
"We're working to secure the necessary replacement parts required and plan to undertake further maintenance at the facility this week."
Avery apologised and acknowledged the unpleasentness for residents and businesses.
"While it's difficult to say how long it will take for the biological process to stabilise and for all odour to dissipate, significant progress continues to be made and we should start to see the smell in the area improving."
It plans to use an odour-control fog cannon to try to improve the smell in the meantime.
There was no health hazard from the problems at the plant, the council advised.
QLDC said the issues with the equipment and biological processes had caused a decrease in the normal quality of treated effluent passing into - and visible at - the disposal field, near Shotover River.
However, the plant's operators were working to return the process to normal as quickly as possible, it said.
QLDC previously stated the earlier repairs were not related to the upgrades underway at the plant to improve wastewater capacity in the district.