Foul smells from Waipukurau's wastewater treatment plant 'spoiled' Christmas

CHB District council says it is pleased with how the new deodorising misting system has been working at Waipukurau's wastewater plant

The latest measure to stop offensive odours emanating from Waipukurau's wastewater treatment plant has been ineffective so far over summer, according to one nearby resident, who says the stench from the plant spoiled Christmas Day for her and others.

In another attempt to solve the odour problems which have now been ongoing for more than year, CHB District council spent $30,000 before Christmas installing a new deodorising misting system around the plant's oxidation pond, where council says the smell is originating from.

The new system pumps water mixed with a small amount of deodoriser through 150 elevated nozzles spread 300 metres around the edge of the pond.

Council said it has received positive feedback about the effectiveness of the system since it was installed, but Mt Herbert Rd resident Catherine Ashby said the smells have continued largely unabated and forced her family to spend Christmas Day indoors.

"So much for enjoying the lovely weather and festive season, huh? We have not had one meal or one cup of coffee at the barbecue table this summer season because it still stinks," said Mrs Ashby, who added she was not the only one impacted on Christmas Day.

"An elderly couple have had family Christmases at their place for the last 20 years, but cancelled this [year] due to the stench."

Council chief executive Monique Davidson said the deodorising system was recommended as one option to reduce the "nuisance" smells emanating from the site.

Before installing the system, Ms Davidson said her staff talked with Wanganui District Council staff who used a similar system when they had problems with their wastewater plants, and had found it effective.

"The misting system intercepts the smell drifting from the site, and under some conditions the smell may escape around the edges of the misting line. Council has received mainly positive comments about the reduction of the nuisance [odours] since the misting system was installed."

But Mrs Ashby said even since the system was installed, it was "only the odd time" that the plant was "stench-free".

"This ongoing stench impacts on my daily quality of life, so it's quite insulting that they [council] think it's just a nuisance."

Mrs Davidson said after the installation of the misting system, no more temporary work was planned to combat the problem.

"The specialists say that if council has enough aeration in the pond, the smell problem will stop. Two extra aerators will be installed in February, making a total of six installed aerators."

She said council would now focus on the short-term recommendations included in an independent review of the plant carried out last year by The Wastewater Specialists, before working on a long term solution.

Despite $8.6 million being spent to date since they were commissioned in 2012, The Wastewater Specialists' review confirmed that neither of the council's wastewater plants in Waipukurau and Waipawa will meet resource consent conditions, and that anywhere between $11.9m and $36m might need to be spent to make them compliant.