Residents living near Wanganui's wastewater treatment ponds have been asked to log any strong smells from the area in future.
This is one outcome of a meeting Wanganui District Council representatives had with residents on Tuesday night, explaining problems that mean the treatment plant is in breach of its consents.
Horizons Regional Council has served non-compliance notices on the council because discharges from the plant have been exceeding limits allowed.
The district council has launched remedial action to bring the treatment system back on track, introducing bacteria to accelerate the breakdown of waste in the ponds.
Currently, the process is not working as it should be and, as a result, the level of bacteria discharged into the sea off South Beach is higher than Horizons consent allows.
The discharge levels do not pose any health or environmental risk.
The treatment plant, behind the city's airport, was commissioned in 2007 and marked the final stage of the city's $120 million wastewater separation and treatment project. But from the start it has been dogged with problems.
For the past three years, especially, people living in the area have complained of strong odours.
Councillor Ray Stevens, chairman of the council's infrastructure and property committee, told the Chronicle yesterday the meeting gave residents a thorough explanation of the problem and what was being done to correct it.
"And we apologised for what they've had to put up with on and off over the last three years," Mr Stevens said.
He said council would give updates in six weeks' time and again before Christmas.
The bio-augmentation programme is expected to be on site by the end of this month and microbes put into the treatment ponds soon after. Council officers say they expect the problem to stabilise and then improve before Christmas.
"We'll have some indication by then of how things are going," Mr Stevens said.
He said council had set up a dedicated point of call for the residents when they noticed any strong smells in the area.
"Every time they do, we've asked them to call us so we can log the time and date and then see if it's coming from the ponds. It could be a smell coming from one of the wet industries on the other side of the river," he said.
"But we know that whenever smells vent from the treatment ponds, it's a real bad smell," he said.
The consents for the ponds demand that suspended solids must not exceed 100 parts per million (ppm) but currently it was running at about 180 ppm. The quantity of suspended solids meant the final treatment of the waste - with ultraviolet light - could not work properly. That meant the faecal coliforms discharged exceeded consent limits.