Rotorua council asks residents to be 'vigilant' about what they put down their sinks, drains and toilets

A fatberg blocked a pipeline and caused a wastewater overflow in Linton Park. Photo / Supplied

Rotorua residents are being urged to remain vigilant about what they're putting down their sinks, drains and toilets after a wastewater overflow caused by a "fatberg".

A fatberg – a mass of fat and other non-biodegradable solids like wet wipes – blocked a pipeline that caused a wastewater overflow from a manhole in Linton Park yesterday.

The overflow, which was confined to the immediate area around the manhole, was cleaned up and the area disinfected after it was reported by a member of the public. Signs in the vicinity, which includes a wetland/swamp area, warn against contact with water as a precaution.

"Fatbergs cause a back-up of sewage in the pipeline and manholes become the overflow point," Rotorua Lakes Council Infrastructure Networks Performance Manager Eric Cawte said.

"This weekend's incident was fortunately confined to a small area which reduces the public health and environmental risk, but we would urge the public to please be vigilant about what they're putting down their sinks, drains and toilets."

Fatbergs are made up of a mixture of solidified fat and cleaning wipes – neither of which should be in the wastewater system. Two overflows in the city earlier this year were also caused by fatbergs and this latest incident is another reminder for the public, Cawte said.

"We have a large wastewater network so faults are inevitable, but incidents like this weekend's overflow are largely avoidable.

"Even products that are supposedly 'flushable', according to the packaging, can result in significant issues for our wastewater infrastructure and, more importantly, for our environment."

Council contractors responded to the overflow yesterday and after cleaning up and disinfecting the area erected signage which will likely stay up for a couple of days as a precaution, Cawte said.

The overflow was reported by a member of the public at about 10.45am yesterday and contractors who attended notified TRILITY, which manages the city's wastewater network, due to the risk of contamination of the wetland/swamp area near the manhole. TRILITY notified Toi Te Ora Public Health, BOP Regional Council and Rotorua Lakes Council and a follow-up clean-up was undertaken today.

Cawte said there are a large number of pipes and manholes in the Linton Park area, servicing a large part of the city, but the overflow yesterday did not reach the Mangakakahi Stream.

Cawte said when wastewater overflows out of the network, the natural course of flow will take it to the lowest ground levels, as occurs with rainwater.

"Streams and creeks running through our neighbourhoods are part of the natural stormwater system and are the lowest points. Wastewater flows the same way as stormwater.

"We need the community's help to do what we can to avoid blockages and keeping our systems free of foreign substances and objects is the best way to do that."

As the overflow was confined to the immediate area surrounding the manhole, signage was used to notify users of the area to warn against contact with water.

A wider public notification would have occurred had the risk or impact been wider or more significant.

Info and facts:

• Wastewater comes from your kitchen and laundry sinks and appliances, from showers, baths and toilets.

• Get rid of cleaning wipes in the rubbish bin – don't flush them.

• Let fat solidify and then dispose of it in the rubbish bin.

• Council owns and maintains approximately 500km of gravity mains, 8000 manholes and more than 20,000 homes and businesses are connected to the wastewater network.

• Items that have been found in our wastewater network include not just wet wipes and solidified fat but also children's toys, cutlery, an oil can, building materials, a hedgehog and a pig's head.

- Supplied content