Seaview residents and business owners say the stench is still unbearable from the local wastewater treatment plant.
They have been battling with the smell for years, however, what one resident described as the smell of "hydrogen sulphide and faeces" has only become worse in recent months.
Ranjini Singh from Electrotech said her commercial building had installed its own air fresheners, at the cost of a couple of hundred dollars.
She felt embarrassed when customers visited her business because of the smell outside.
Singh said she complained to the council twice in recent months, and nothing had changed.
Steve Henderson, the operations manager of a nearby moving and storage firm, said his staff suffered from headaches and nausea from the never-ending smell.
He said the additional chemicals pumped out by a second deodorant cannon - added in the last month - just brought a different flavour to the odour.
"You've sort of got the smell of the matter coming out of there and then it seems be when it's mixed with that it would be like if someone used the loo and sprayed some spray and when you go in there it smells even worse."
Henderson said he had canvassed 30 businesses in the area - representing over more than 500 staff - who had agreed to sign a joint letter to the council over the problems with the plant.
Hutt City councillor Brady Dyer told Midday Report the Seaview Wastewater Treatment Plant's odour issues were part of a wider lack of investment in treatment plants.
"I'm confident we're doing everything we can. It's just been an unfortunate string of failures at the plant."
Last year the plant's biofilters failed, and the recent issues were caused by a sludge dryer catching fire, Dyer said.
Recently, a second deodoriser was installed to try to control the stench.
"The deodoriser makes it slightly more pleasant, but it's still not not a pleasant smell," Dyer said.
Although they were not an ideal solution, they would have to do while the council upgraded the plant, he said.
"The deodoriser is kind of the ambulance at the bottom of the cliff."
'Explicit in your mouth'
Anthony Coomer works at motorsport seat manufacturer Racetech on Barnes Street, about 300m from the plant. He told Checkpoint on Thursday afternoon the smell was "unbelievably pungent".
"It makes you gag. You can often taste it before you can smell it - that's how bad it is. Like, you drive down the street, you drive past on a still day or less wind it's probably worse, but it some days it's different smells, and it's all, you know, kind of along the same lines - just rank s***, explicit in your mouth. It is really bad."
He said he had to hold his shirt over his nose whenever he walked nearby, and felt sorry for kids visiting a marae just down the road.
"You see them all having to put cloth over their face or something like it. It's like a dead body. Some days it's really bad … you're sitting at your desk and all you can smell is just crap all day long, you know?"
He said the council's efforts to deodorise the smell have not worked one bit.
"We're just lucky here in Wellington that this time of year it starts to get windier … the council can say whatever they like - I'm here every day … they can call it a mask, a deodoriser or whatever, but in my mind, it's just doing nothing."
He estimated perhaps a quarter of the entire city could smell it.
Wellington Water has apologised for the odour, and said it was doing all it could to stabilise the plant after the dryer outages.
Work had recently been completed to repair the sludge dryer which broke down in September, a spokesperson said.
"We are working as fast as possible and doing all we can to stabilise plant operations, following the sludge dryer outages. We are focused on returning the plant to normal operations.
"The backlog of sludge is reducing, and we are continuing to transfer it to landfill. The sludge dryer operation is functioning as expected."
Upper Hutt mayor Campbell Barry said he expected work to bring the plant up to compliance would be completed in up to 18 months.
But he said the work would not stop the smell completely - just render it less "objectionable".
"The consent does not allow for 'objectionable odour' - and there is a test from the regional council on that - to exceed the plant's boundaries. That doesn't mean that there won't be a level of odour that goes beyond the boundaries in the future."
Responding to critics online in September, Barry said Wellington Water had been set up to fail by insufficient funding and the scrapping of the Three Waters plan.
He wrote that people had a right to vote for a different mayor if they were unhappy but warned that any candidate who promised a quick fix to the plant's woes would be dealing in the "voodoo economics" that had led to infrastructure problems across the country.
"We are doing everything we possibly can to rectify this issue and it is an absolute top priority. But anyone who says that they will be able to eliminate the odour completely is lying because that is not how the plant was consented and built."
Barry said the safety of the deodoriser cannons had been evaluated and verified by Health New Zealand.
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