Discharging untreated wastewater into the sea is "not an option" for the Wanganui District Council, says Mayor Annette Main.
She was responding yesterday to comments made by retired engineer Colin Hovey in the Wanganui Chronicle on Tuesday.
Since December, Wanganui's wastewater treatment plant has been overloaded with trade waste - protein and hydrogen sulphide - that has left a stench hanging over parts of the city.
Mr Hovey, who helped design the beleaguered wastewater treatment plant, said excess waste should be put straight out to sea while issues with the overloaded plant were being rectified.
But Ms Main said disposing of untreated waste to the sea would potentially cause further problems.
"While the smell some residents are enduring is unacceptable, I'm sure most people would rather that than risk public and environmental health," she said.
Mr Hovey noted the council once disposed of wastewater to the river and sea.
"We did it for 20 years," he said.
Ms Main said: "Just because that's what happened in the past, it is not a good enough reason for us to risk public health now".
She pointed to the $120 million spent on cleaning up the river and, by association, the ocean through the council's wastewater scheme.
"I've seen the effects on the treatment plant ponds of huge quantities of protein and sulphides being discharged in the system in the last few weeks.
"It is disgusting and I dread to think what the effects on people and the environment might be if that material was discharged directly into the sea."
The council's infrastructure manager, Mark Hughes, said the treatment of wastewater at the plant would be boosted from today by the arrival of additional personnel, equipment and treatment materials from Hastings.
"We are also undertaking, by boat, another sludge survey this week to check on the depth, density and composition of the sludge across both ponds," he said.