DIRTY JOB: Rotorua wastewater treatment plant operator Shaun Lockie at the Te Ngae Rd plant. PHOTO/BEN FRASER
DIRTY JOB: Rotorua wastewater treatment plant operator Shaun Lockie at the Te Ngae Rd plant. PHOTO/BEN FRASER
We're flushing loads of garbage down our toilets
People flushing "flushable" wet wipes down the toilet are contributing to a clogging up of Rotorua's sewers.
The wipes and other solid objects flushed down the drains are jamming the city's pumping stations.
This can lead to sewer overflows which risk contamination of private and public property, waterways and lakes.
Rotorua Lakes Council has provided a list of items found in the pumping stations, which includes false teeth, jewellery, a hedgehog and even a pig's head.
There are 79 sewage pumping stations across the city carrying wastewater from homes and businesses to the wastewater treatment plant.
Council water operations manager Eric Cawte said in the past the screens at the wastewater treatment plant were cleaned manually. "Cash, dentures and jewellery were among the items found," he said.
"Now cleaning is automated and everything caught in the screens goes directly to skips for disposal. In the recent past, blockages in pump stations, pipelines and manholes have been found to have been caused by blocks of wood, punga, toys, cutlery, a hedgehog and a pig's head.
"Solidified fat also causes problems from time to time, often exacerbated by items such as those listed above."
Most of the pumping stations are found in the urban areas but there are several in lakeside communities including Okareka, Mourea and Hamurana.
The council also has around 1300 low pressure grinder pump installations on private properties in lakeside communities.
"On average we experience about 20 pump blockages a month and about 13 blockages in the pipe network per month," Mr Cawte said.
"Most of these are attended to and cleared before overflows from the system occur."
He said council didn't have a definitive list of forbidden items but there was a bylaw which regulated discharges from businesses such as chemicals, hazardous substances and fats.
It also has general provisions prohibiting people from doing things which may cause damage to the network.
He said there were also guidelines issued to properties connected to a low pressure grinder pump advising of items that should not be put down the sewer system.
"We try to minimise adverse effects by education and enforcement through our trade waste and pollution control team with the aim of minimising inputs such as chemicals and fats from businesses. We also have a monitoring and alarm system in pump stations which gives early warning of pump faults and blockages, and we have a programme of regularly cleaning the 520km of sewer pipes in the network, with emphasis on pipelines known to be prone to fat and other blockages."
Found in Rotorua's wastewater system -Blocks of wood -Cash -False teeth -Jewellery -Punga -Toys -Cutlery -Hedgehog -Pig's head -Solidified fat
Rotorua's wastewater treatment -79 pumping stations -20 pump blockages a month -About 13 blockages in the pipe network per month - 520km of sewer pipes in the network
