The Carterton wastewater treatment ponds off Dalefield Rd. PHOTOS/TOM TAYLOR
Carterton keen for bad smell to go
Carterton residents have put up with a week-long stench as their wastewater treatment ponds undergo treatment of their own. As reporter TOM TAYLOR discovered, the only residents safe from the stink were those without a sense of smell.
Carterton District Council first drew attention to odours at the south end of town last Thursday with a post on their Facebook page: “We’ve become aware of an unpleasant smell at the south end of town. We’re working on the issue, and it will be resolved as soon as possible.”
The council later updated their message with further information on the root of the smell.
The treatment ponds off Dalefield Rd had received a heavy load of ‘non-wastewater’ through its pipes network. A solvent-based chemical in this load had killed off the ‘good’ bacteria in Pond 1 that would normally digest the organic material.
Council workers had pumped wastewater containing live bacteria from one pond to another to treat the bacteria-free water.
They stirred up the wastewater to provide oxygen for the bacteria to survive.
A direct result of disturbing the surface of the wastewater ponds was a sulphuric smell that has plagued residents in the week since.
“The poo smell? It makes you gag. It’s absolutely awful. It’s like Rotorua on a good day,” Dalefield Rd resident Carlene Smith said.
She had lived on the road for “four Olympics” and said she was over it.
“My rates are just under $5000 a year, and I have to smell that? What am I paying my rates for?”
Smith said this latest issue reminded her of Carterton’s other water woes. In March and April, Carterton residents endured on-and-off notices to boil their water after high E. coli readings in the town’s network.
Phil and Miriam Gates were renovating a house on Lincoln Rd and drove past the ponds most days.
Phil could not comment on the stench, saying he had no sense of smell.
However, his wife Miriam had noticed it “big time”.
“It’s bloody horrible … I thought it would go away by the time we got here [to Lincoln Rd], but it hasn’t.”
“I’m wondering what they’re doing to make it like that because it’s not as if there’s any breeze blowing this way.”
The Gates were left wondering how the smell would impact their renovations and the overall appeal of their house.
Other residents took to social media to express their irritation.
One resident said the odours were not limited to the south side of town and had wafted as far north as Carterton New World.
Another resident decided the town should be renamed “Farterton”.
Mayor Greg Lang said he could understand residents’ frustration.
“I would like to assure them that the council is working as fast as it can to alleviate the odour. I am confident that through the work of the management staff and the external experts they have engaged, we will resolve the issue promptly and prevent a reoccurrence.”
Council had borrowed an additional aerator to help raise the dissolved oxygen levels in the ponds.
On Wednesday, council operations managers had met Napier-based sewage disposal company Parklink, who would supply extra bacteria to add to any bacteria that was still alive in Carterton’s ponds.
The council was also dosing the ponds with calcium nitrate to alleviate the odours.
Council infrastructure, services, and regulatory manager Dave Gittings, said the calcium nitrate would suppress the smell as much as possible.
“That’s pretty much all we’ve got – that’s the only thing in the armament to do that, so we are limited with what we can do.”
Gittings said it was likely that someone had disposed of the chemical load that had caused the pond’s problems using one of the manholes in Carterton.
To prevent a similar situation from occurring again, the council was seeking a new 30,000-litre tank.
“If we have a separate loading tank, then we can drip-feed back into the ponds and check the health of it, so we can dose it and make any changes to pH level or whatever is required to treat it a little before it goes into the pond. It just gives it that break.”
In the meantime, Gittings said that getting the bacteria working again was key to the health of the ponds.
“It’s the ammonia that smells. When you have good bacteria, they eat the ammonia and turn it into nitrate, but when you don’t have the bacteria – which was knocked off through the chemicals that were deposited into the ponds – we have a bad smell.”
