Whanganui council not concerned by increase in odour complaints at wastewater treatment plant

The wastewater treatment plant has been fully operational since 2019. Photo / NZME

Complaints about odour from Whanganui’s wastewater treatment plant have increased, but the district council’s infrastructure boss says he is not concerned.

There were nine reports of odour in February, up from one in February 2024 and two in December 2024.

At a Whanganui District Council operations and performance committee meeting this month, senior wastewater engineer Tony Hooper said when there were more complaints, it was usually assumed that “something has broken down”, but that was not the case at the plant.

“In February, we started getting complaints from the gun club, which is just over the fence in a northerly direction,” he said.

“I’ve been over there and they’ve got my number now.

“They text me every time they go there and smell something.”

There are two gun clubs near the plant – the Wanganui Pistol Club and the Wanganui Handgun Silhouette Association.

In a statement, the council said it met with complainants at the Wanganui Pistol Club site.

Council chief infrastructure officer Lance Kennedy said he was not concerned by the increase in complaints.

Historically, there had been a perception from people most affected by odour that they were not being heard by the council, he said.

“We’ve kind of worked out that part of that was our lack of communication to them.”

Kennedy said that the process had been improved.

“Potentially, there is room for those calls to keep increasing.

“We’d rather hear than them not get hold of us because they think we’re going to do nothing.”

A council report from August 2023 said there had been 14 complaints about odour that year, with 12 coming from Mid West helicopters, the plant’s nearest neighbour.

The $39 million plant has been fully operational since February 2019.

Lance Kennedy says there was a perception that people making odour complaints were not being heard by the council. Photo / NZME

Hooper’s report to the committee said there was $300,000 in the council’s 2026/27 budget for a carbon filter, which would be fitted in the plant’s dryer to help with odour.

However, chief executive David Langford was keen to bring that forward to 2025/26, he told the committee.

If that did not happen, the officers would be “ready to go” in July 2026.

“The dryer is the biggest producer of odour out there,” Hooper said.

His report said a shutdown of the drier was planned in September so officers could “carry out inspections, cleaning and maintenance as required”.

“This is going to require co-ordination of several contractors and suppliers who are being consulted now.”

That project is estimated to cost $80,000.

The drier was shut down for two weeks last year, with “two significant issues” identified and corrected.

At the time, Hooper said putting sludge through the dryer reduced it by five or six times.

“The fact, we put it through a dryer and it goes through those heat extremes means you can do more with it as a finished product as well,” he said.

“When you put [sludge] through a decanter and you’re just removing some water, you’re not actually treating any bacteria in there.”

His report said another project to mitigate odour was repairing the cover of the plant’s anaerobic pond, which was completed last November for $26,000.

“Early indications are this was very successful.”

Mike Tweed is a multimedia journalist at the Whanganui Chronicle. Since starting in March 2020, he has dabbled in everything from sport to music. At present, his focus is on local government, primarily the Whanganui District Council.