The Watiaki District Council is reconsidering the future of the facilities because illicit dumping of other waste is clogging the Oamaru waste water treatment system.
At a council activity update meeting last week, councillors were told "new arrangements" were being worked through.
"The Oamaru wastewater treatment plant is no longer able to take the effluent due to capacity issues," a staff report said.
The facilities operate in Waitaki on State highway 1, at Palmerston, and just north of Oamaru. One option was to "potentially close" both or one of the sites, infrastructure manager Joshua Rendell said under questioning.
Cr John McCone said he wanted more information.
"Why have we got capacity issues now?"
Mr Rendell said other waste was thought to be the issue.
"Someone has been dumping material at stock effluent facilities which is not stock effluent, either fats, greases or oils.
"Because of that significant loading, the treatment plant can’t cope at the moment."
This had been detected through periodic sampling when the stock effluent points were emptied.
"We are not able to take stock effluent to the Oamaru Waste Water Treatment Plant at the moment. There’s some capacity issues there.
"We’re looking at other options," Mr Rendell said.
Mayor Gary Kircher asked if CCTV surveillance was being considered.
Mr Rendell said that was an option and would entail regular footage reviews to "hopefully" catch the culprit.
The "next best option" was to cart stock effluent to Timaru at "a significant cost".
"The other option is Dunedin. We don’t have other sites for stock effluent (disposal)."
Cr McCone asked whether the effluent could be spread "back on the paddocks from where it came from".
Mr Rendell said that was a "great question", but a resource consent would be needed in order to dispose the effluent to land.
