‘Four more years of stench’ makes an attention-grabbing headline but it’s misleading in terms of the messages delivered at this week’s public meeting on the Seaview sewage treatment plant.
It wrongly gives the impression we’re stuck with the current level of stink for the foreseeable future. In fact, there are grounds for optimism that odour improvements might only be a month or two away as moves to get complicated systems that govern what is a live biological process back into balance.
What has to be admitted – and was admitted by Wellington Water and contracted plant operated Veolia at the meeting – is that even as upgrades costing tens of millions of dollars are pursued, no-one can guarantee there won’t be repeated spells of the present nauseating smell.
Mayor Campbell Barry was upfront with the 25 or so community members who turned up to the November 25th meeting, several of whom were in tears over their utter frustration with the ongoing problems at the Seaview plant.
The mayor said the current levels of stench were “totally unacceptable” and far below the level of service residents and ratepayers deserved.
There’s $225 million in Hutt City Council’s 10-year plan for wastewater issues, and dealing with the Seaview plant odour is the city’s top priority. Replacing significant components of the plant are being front-loaded into the first three or four years of the Long-Term Plan.
The wastewater treatment issues stem from ageing parts and infrastructure, and are a symptom of what we’re seeing with 3 waters networks not just in the Hutt, but up and down the country, Mayor Barry said.
As several of the residents pointed out, smells from the plant have been ongoing for years. But they’ve been much worse this year.
A number of them said the odour neutraliser spray “blasters” brought in to try to combat the stink are making things worse. As well as the smell of s***, the blasters added a very unpleasant chemical tang, they said.
While the neutralisers are considered ‘industry best practice’, it was agreed at the meeting there should be trials – with plenty of community warning and monitoring – of switching off the blasters, and gauging the community’s reaction.
What’s going wrong?
A project to replace media in six biofilter cells turned out to be much more complicated and fraught than envisaged. They had to be done all at once because no system was in place to allow them to be done one by one.
There is now a new air distribution system associated with the biofilter cells, and new isolation valves.
Next planned stages are to improve the capture of odours not currently reaching the biofilter for treatment. So that’s new odour treatment in the milliscreening building, replacing the milliscreen ducting, and fixing external leaks in external odour ducting at the plant.
Further disruption – and stench – resulted from two small fires in the plant’s sludge dryer – incidents Wellington Water admitted at this month’s meeting occurred because plant staff did not follow process guidelines. The dryer was offline for nine days, but was then taken out again by a component failure.
There was also a failure in a primary settling tank.
Tens of thousands of tonnes of de-watered sludge have had to be trucked to Silverstream landfill while the dryer was fixed. It added to odour issues.
Full descriptions of planned upgrades can be found here.
Too slow
Pat Dougherty, Wellington Water’s (WWL) new chief executive, told the meeting maximum focus is being given to getting the plant’s processes back in balance.
He admitted WWL and Veolia had been too slow to detect that various components at the plant were wearing out faster than anticipated.
WWL is building its asset management capacity and there is much closer scrutiny of components.
He spoke of changing the relationship between WWL and Veolia (an international company that runs all of Wellington region’s sewage treatment plants) as one of emphasising preservation of a good working relationship to one with “more tension” over contracts.
Mr Dougherty didn’t say it, but reading between the lines that could be translated as Veolia has been given a rocket to lift their game. Additional experience staff are being brought in; others are being upskilled.
As upgrading work continues around the plant, there were repeated assurances a key consideration at each stage would be the impact on odours beyond the plant boundaries.
One large upcoming expense is a new sludge dryer, with a price tag of around $92m. It’s to be built on adjacent land currently used as a car lot, and with sea level rise in mind. Upgrades to at least one sub-station will be needed so that it can operate on electricity, rather than expensive – and climate emissions-unfriendly – gas.
While Mr Dougherty said money was not the issue – the Hutt and Upper Hutt councils were fronting with the funding that’s needed – there is significant concern about the workforce. There is a global shortage of specialist expertise in the wastewater sector.
His final word at the public meeting was to implore councils and the Government to get on with the move to new 3 waters infrastructure companies under Local Water Done Well.
“We need to make decisions fast or we’ll lose workforce.”
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