Source: Radio New Zealand
Diggers working at the burnt-out Bromley wastewater treatment plant. Christchurch City Council supplied pictures and video of work to remove rot from inside its filters on 10 June 2022. Christchurch City Council
Christchurch city councillors has voted to add more air to sewage ponds at its troubled Bromley treatment plant to reduce the stench that’s afflicted parts of the city for years.
The council backed a staff recommendation to add 16 aerators which will provide oxygen to some of the ponds, assisting in breaking down sewage.
Staff say the putrid stench that has plagued residents on the city’s east since a fire damaged a plant in 2021 is caused by high Biological Oxygen Demand (BOD) levels.
It’s hoped the new activated sludge system the council is building will solve the issue, but with the repairs not due to come online until 2028, a surge in stench over summer resulting in thousands of complaints each month and an abatement notice from the regional council, the pressure was on for a temporary fix.
A controversial plan floated by mayor Phil Mauger which caused backlash in some quarters, raised the ire of the minister for oceans and fisheries and caught the regional council unaware was not recommended by staff who warned of potential environmental and health risks.
Instead, the staff recommendation to add 16 more aerators, which will bubble or pump air into the sewage increasing the ability to break down into CO2 and sludge, passed 15 votes to two.
Staff said this option, which would reduce the risk of offensive smells on 95 percent of days a year, would cost $7.7 million dollars,
Another option to add 21 aerators, which was modelled to reduce the risk on 99 percent of days a year at a cost of $11.2 million dollars was not recommended by staff.
Several councillors noted they would have preferred that option, which added in extra capacity and provided more assurances to local residents, who have suffered from migraines, nausea, respiratory issues and mental health impacts since the 19 day blaze destroyed key infrastructure at the plant in 2021.
“I’m frustrated that we’re not putting up the 99 [percent odour reduction option] first, because I believe we don’t have any social licence out there in Bromley any longer and any possibility of the stench coming back in the future, I don’t believe we have that luxury,” councillor Mark Peters said.
He said the plan couldn’t come soon enough.
“It’s been really tough watching the people in Bromley suffering through this episode and my heart, from the other side of the city, goes out to you.”
Councillor Andrei Moore agreed the option of more aerators should have been put to the vote.
But he said he was relieved something would finally be done, and at staff assurances it would take three weeks to add more aerators if needed.
“I struggle to stand that stench for more than three minutes, I can barely begin to imagine how the locals have gotten by.”
Peters and Moore voted against the 95 percent reduction option.
Councillor Celeste Donovan told the meeting odour from the plant had been an issue in the area for decades, but the worst of it had plagued the area for close to five years.
She said she was also disappointed the more comprehensive option had not been put forward.
“I think we can all agree we’ve heard the community view, and I can say with some confidence this is not the time for anything less than the full option. We need to do it once, we need to do it right.”
She said she would support the 95 percent option, because “we just need to get on and do something”.
But she said the 99 percent option provided a third more aerators, as well as a buffer and redundancy in the system.
“To me that’s good value for money for a community that’s been short-changed for too long.”
While the upfront costs were higher, “we can’t afford any further uncertainty when it comes to this community, and any further impacts that fall on them is a cost we can’t afford to pay.”
Yani Johanson. RNZ / Nate McKinnon
Councillor Yani Johanson told the meeting he would have preferred the 99 percent option.
“We owe it to this community to minimise and mitigate the risk as much as we can, rather than leave any risk that they would go through the hell that they’ve been through in the past, in the future.
“We cannot change the past, but we can change the future,” he said.
“Today is about addressing recognising we’re doing something constructive and positive to address an ongoing issue that has happened in our community, particularly in the east of the city, that’s had an adverse and significantly negative impact.”
The council also passed a motion noting a trial of a “biochemical additive product” to reduce odour was underway, and that staff would apply it more widely if it was found to be effective.
A council spokesperson said they could not disclose details of the product until after the Easter break.
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– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand
