The Queenstown Lakes District Council has been issued with two abatement notices in relation to its Shotover wastewater plant in the past three years, with the Otago Regional Council finding it had been "contravening" its resource consent conditions by discharging untreated wastewater.
In one incident this year, the ORC alleged untreated wastewater flowed into the Kawarau River.
In response to an inquiry from the Otago Daily Times, ORC released the most recent abatement notice — issued in March this year — following issues at the plant.
In a joint statement on Tuesday, the councils said there had been some ongoing challenges at the plant, exacerbated during and after periods of heavy rainfall.
In a statement yesterday, a QLDC spokesman said the council was "confident" no untreated or partially treated effluent had been or was being released from the plant during this latest time, which occurred this week following heavy rain in the area.
ORC chief executive Richard Saunders said his staff visited the site this week and observed a discharge from the site towards the river.
Samples had been taken for testing and results would form part of the most recent investigation.
"ORC remains concerned about the current status of compliance at the Shotover wastewater treatment plant.
"We remain engaged with QLDC staff and continue to undertake our investigation to determine what further action, if any, is warranted."
The district council spokesman said ORC had taken enforcement action consistent with its regulatory role, noting the field’s performance was the subject of two abatement notices and had also attracted "a number of infringement notices".
"Unfortunately, given the nature of the issues, there isn’t a solution that can be readily implemented to enable immediate compliance, and ORC is fully aware of this."
The council acknowledged there were periods this year when the plant’s performance was "compromised as a result of mechanical plant failures".
"In each case, QLDC informed ORC promptly and actively supported its investigations."
The council held a resource consent to discharge treated wastewater to land, subject to conditions.
However, this year’s abatement notice detailed five inspections between December 27, 2023 and February 22, 2024 where breaches had been found.
On December 27, "slightly discoloured, silt-laden" wastewater, which "smelt of sewage", was discharging through the field’s boundary fence, flowing like a "small river" away from the field to where it ponded.
The following day, the regional council found the flow had extended 20m further and wastewater was discharging for about 100m under a gate, where it appeared to "disappear".
"Another large, ponded area of suspected wastewater adjacent to the Kawarau River ... was discharging overland, directly into the Kawarau River," the ORC said.
Samples showed "extremely high" levels of E. coli and "suspended solids".
There were more issues on January 25 and February 21. During the latter visit, earth bunds — containing "a volume of wastewater across the disposal field" — had been constructed around and within the field, which was a breach of a consent condition.
"While observing the disposal field, the internal earth bunds/walls made of earth began crumpling and collapsing."
There were still ponds, and new puddles, outside the disposal field on February 22
Then, on March 3, ORC found a bund inside the disposal field breached, causing wastewater to discharge overland into the Shotover Delta, where it was ponding.
If the district council did not comply with the notice, it may be prosecuted under the Resource Management Act.
In its statement yesterday, the district council said all treated effluent disposed of from the plant passed into the rivers through gravels into shallow groundwater, in line with its consent with ORC.
The QLDC spokesman said the council secured funding through the long-term plan for a "new solution", work on which had started. It has allocated $77.5 million to the wastewater plant.
