Fatbergs: Gisborne district council asked to look at bylaw to prohibit wet wipes
A bylaw to ban the sale of wet wipes in Gisborne has been mooted as a possible solution to fight fatbergs.
Wet wipes do not break down after being flushed down the toilet and are a “huge” contributing factor to blockages in the city's sewer pipes, Gisborne District Council lifelines director David Wilson says.
It has prompted the Kiwa Group, which provides cultural and technical advice to the council on water management, to seek a mandate to investigate a ban on wet wipes.
Karena Toroa, who represents Ngāi Tāmanuhiri iwi on the Kiwa Group, said New Zealand had so far opted for an “educate the public” model to wean off wet wipes, but this was slow.
“It would be a very quick solution if we were to look at just banning them altogether,” Ms Toroa said.
“If you can ban plastic bags in certain countries and certain states, then I'm sure you would be able to ban wet wipes.”
The United Kingdom government in 2018 announced its plan to eliminate plastic waste including “single-use products like wet wipes”.
These were found to be behind 93 percent of blockages in UK sewers.
Fatbergs form when fat, oil and grease are poured down sinks and drains and combine with items that should not be flushed down the toilet, like wet wipes.
Clearing fatbergs has cost Gisborne ratepayers hundreds of thousands of dollars, including a recurring fatberg where the sewer dips down near Mobil Service Station on Wainui Road before it goes up and over the bridge.
The council spent about $4500 to clear a 400-kilogram fatberg at this location on August 16. The council said it was caused by a “load of fat” tipped down the drain and was following up with the parties involved.
It follows a $15,000 spend clearing a fatberg made up largely of fat, wet wipes and rags at this location in June 2020 and a $100,000 spend two years earlier at the same location.
In addition to the financial cost, the blockages sometimes result in overflows of the wastewater system during storm events, which mean the council must open the sewer valves and human waste is released into city rivers and the sea.
Tangata whenua have long voiced strong opposition to this practice, saying the discharge of sewage into the awa (river) is offensive to tikanga Māori.
“Our cultural values are a little bit different. We don't like to mix wastewater or mortuary wastewater with where we get our kai. That, to us, is not acceptable,” Ms Torea said.
She acknowledged the idea wouldn't necessarily be a hit with everyone.
“I've been a mum — my kids are all grown up — but I know how convenient wet wipes are.”
The concept of using a bylaw to ban wet wipes follows a new trade waste bylaw passed in Gisborne that bans mortuary waste from entering the public wastewater system.
The Kiwa Group front-footed the proposal, which some members referred to as a “respect and dignity” bylaw that brought an end to the “culturally abhorrent” practice of sending mortuary waste to sea.
Ms Torea said they were starting to feel “momentum” on water issues.
“It wasn't actually us who started it. It was all our grandparents. They didn't so much have a voice but they've always been pushing these issues.
“I think now with the Kiwa Group being able to continue to work with the council, we finally do have a say where we can marry up our individual values and work together.
“We've finally got a voice to be able to say ‘let's find some solutions'.”
Mr Wilson said he wasn't aware of any other council that had attempted to use a bylaw to ban wet wipes.
The council has run a campaign reminding the public that “sinks are not rubbish bins” and to “please only flush the 3 P's — pee, poo and toilet paper”.
Gisborne District Council senior wastewater operations engineer Phil Dodds said on the Monday before lockdown (August 16) they noticed on their computerised monitoring system that the flow was beginning to back up going across the Gladstone Road Bridge.
As the sewer is under the left turning lane from the port it takes considerable coordination to set up and work safely in this location, he said.
It was another 400kg fatberg in a 500-millimetre diameter pipe and was about eight metres long.
Fatbergs occur at the Wainui Road location because the sewer dips down before going over the bridge in what is called a syphon.
“Floating fat concentrates here and sticks to the top of the sewer main, slowly restricting the flow.”
There are six major syphons in the network that are regularly monitored.
“We only checked and cleaned the Wainui syphon six weeks earlier so this was a not typical build-up pattern.
“It was simply a load of fat that had been tipped down the drain going into lockdown and the sewer/trade waste team know where it came from and are following it up with the parties involved.”
The council had additional equipment available to manage fatbergs these days.
“It takes a day for us to set up and remove this kind of fatberg so we estimate it cost $3500 for the contracting and $1000 for traffic management.”