Sewage structure "could collapse" as vital tests due

The Queenstown Lakes District Council is sticking to its "there's no problem" approach to the failed Shotover sewage waste treatment plant even though their own infrastructure manager, Tony Avery, told a council meeting in June this year that the plant's dispersal field has "failed" and has been "known about for some time."

Experts who have spoken to Crux, and been directly involved in trying to maintain and fix the broken Shotover waste systems, say an emergency 3 metre high earth bank built earlier this year around the dispersal field "could collapse at any time producing an environmental catastrophe." ORC investigators have already witnessed parts of the bank collapsing and included photographs in their latest 2024 abatement and infringement notices.

A partial collapse of the emergency Shotover dispersal field earth bank - photographed by ORC investigators earlier this year. Source: Otago Regional Council.

The QLDC has been claiming throughout November, including to local MP Joseph Mooney, that the water being discharged from the failed and blocked dispersal field is safe and treated. However tests in late 2023 and earlier in 2024 by the ORC showed extremely high levels of e coli and suspended solids in water that was being discharged from the field. The QLDC has even denied to Crux that any water is being discharged from the field - and yet they also say there's "no solution" to enable compliance with the council's wastewater consent conditions.

These are the QLDC's latest statements on the situation:

"For clarity, all of the treated effluent disposed of from this plant passes into the rivers (through gravels into shallow groundwater) in line with our consent with ORC

"No untreated or partially treated effluent has been or is being released from the WWTP during this time, i.e. when high levels of rainfall in September and October put additional pressure on the disposal field.

"These (ongoing challenges) are exacerbated during and after periods of heavy rainfall like we have seen in recent months. No untreated or partially treated effluent has been or is being released from the WWTP (Shotover sewage plant) during this time.

"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."

QLDC has no consent to discharge wastewater beyond the field perimeter.

Every single source spoken to by Crux over the past month has confirmed the same timeline of events - events that mean the three main ponds (visible from SH6) are not functioning properly either and allowing solid human waste to enter the dispersal field. The field is only designed to cope with liquid waste.

The UV process building between the 3 main ponds and the dispersal field can't cope with or treat solid waste and there's no way to pump it back to the main ponds.

The solid waste has permanently blocked all of the filtration systems in the bed of the dispersal field (filter baskets, water cells, pea gravel and a textile filters) meaning sewage can't be filtered then drain into the land as designed - and consented.

Instead the liquid and solid waste is being discharged into the Kawarau River.

Local MP Joseph Mooney has been told by QLDC there's no risk to the environment or public health as the discharged wastewater is "treated."

Joseph Mooney told Crux this weekend:

"I am advised that treated water is entering the dispersal fields - not sewage. You would be best directing any further questions regarding that to the organisations that are responsible for the plant and monitoring and enforcement, as I do not have any further information available to me."

Mr Mooney will be left in a difficult position if the "treated water" the he's been told about is the same treated water that ORC has previously found to have introduced "extremely high levels of e coli and suspended solids" into the Kawarau River.

These are the ORC test results of a December 2023 discharge from the dispersal field into the Kawarau River - showing "extremely high level" of e coli and total suspended solids (TSS).

The Kawarau River has special environmental protection under a 1997 Conservation Order.

This is the timeline Crux has documented from multiple sources close to the Shotover project since construction in 2018.

Costs were cut but designing a gravity fed filtration system as opposed to a pressure fed system. It was also an iwi condition that the field be gravity fed.
Early evidence of soakage and flow from the dispersal field being inadequate and not to spec.
Contractors experiment with changing the chemical balance and filling then emptying different water cells within the field
Within 18 months the problems get worse and contractors start digging new channels and ponds including an “emergency” channel on recreational reserve land towards the Kawarau River.
The emergency channel is then decommissioned on instructions from the ORC.
QLDC managers have been aware during all of the early period that partially treated effluent was reaching both the Kawarau and Shotover rivers.
Contractors get blamed for the problem and some team members are removed as “scapegoats” and a new team put in place.
These team members who get removed include one man in particular who had become an expert at trying to contain a delicate "juggling act" chemical balance within the failing field.
Things then continued to get worse and contractors discover ( "to our horror" is a quote) the actual cause of the problem is solid human waste making its way into the disposal field.
This is a major design fault and there’s no physical filtration or pumping to return solid waste back to the first treatment ponds from the UV treatment building. The field is only designed for liquid waste.
The solid waste proves virtually impossible to control and new algae starts to form causing further permanent blockage in the field.
The blocked gravel bed starts to overflow and become inundated. More effluent reaches the rivers.
A permanent overflow pond is built to discharge wastewater to the Kawarau River
QLDC contractors build a massive 3 metre earth bank around the field - without resource consent. There’s no evidence QLDC even told ORC what they were doing.
Effluent flowing south through the recreation reserve gets underneath a large raised rock bank (part of the Twin Rivers Cycle Trail) and then flows freely into the Kawarau.
The field bank needs to be built higher and higher as the water level rises. Parts of the bank collapse (see photo above) during an ORC inspection
More material is trucked in to further increase the height of the bank.
The bank is exposed to the risk of a total collapse that would spill unprecedented amounts of effluent into local rivers.
November 2024 ( and earlier) increasing amounts of partially treated sewage are released into the Kawarau and Shover rivers.