Frequently Asked Questions - Shotover Wastewater Treatment Plant

Why is there a bad smell near near the Shotover Wastewater Treatment Plant?

Urgent repairs were required at the Shotover Wastewater Treatment Plant in December to address an issue with the sludge processing and dewatering system at the facility.

This system is essential for keeping the biological processes that are responsible for the treatment of wastewater healthy.

Repairs were made, but a secondary problem with the facility’s aeration grids has since occurred.

How do the aeration grids affect odour?

Faults with the aeration grids at Shotover Wastewater Treatment Plant mean the reactor used to treat wastewater onsite is receiving coarse aeration, instead of fine bubbles. The high surface area of fine bubbles is integral to allowing oxygen to transfer into the biomass being processed, leading to a reduction in odour created.

Why haven’t the issues been resolved yet?

Issues with the sludge processing and dewatering system at the Shotover Wastewater Treatment Plant have been resolved. However, a secondary problem with the facility’s aeration grids has since occurred.

We’re working to secure the necessary replacement parts required and plan to undertake further maintenance at the facility this week – dated Tuesday 19 December.

When will the smell go away?

While we continue to work on resolving the new problem at the facility, we also need to give the bacteria that treats the wastewater time to do its thing. It’s difficult to say how long it will take for the biological process to stabilise and for all odour to dissipate, but significant progress has been made and the community should notice things improving.

In the meantime, plans are in place to operate an odour mitigation cannon at the Shotover Wastewater Treatment Plant, using a water-based fog to encapsulates smell before it moves off-site.

Is there a health hazard as a result of these issues?

No, there is no health hazard as a result of the issues at the Shotover Wastewater Treatment Plant.

Is this affecting Shotover River?

All wastewater entering the Shotover Wastewater Treatment Plant is treated prior to being discharged to the environment. The temporary issues with the equipment and normal biological processes responsible for the treatment of wastewater have caused a decrease in the normal quality of treated effluent passing into – and visible at – the disposal field. However, the plant’s operators are working to return the process to normal as quickly as possible.

How long is this going to take to fix?

We’re working to secure the necessary replacement parts required and plan to undertake further maintenance at the facility this week – dated Tuesday 19 December.

Where do I get updates on the repairs?

Further updates will be provided once the replacement parts are installed.