If Whangārei's wastewater treatment plant could talk, this Christmas it would be asking for a healthy gut with happy little microbes munching on good, tasty, nutritious, poison-free sewage.

It might seem like a strange request but the city's "gut" has had enough of stomach upsets caused by things like disinfectants, detergents, solvents and other substances that are poisonous to bacteria being poured into the sewer network.

Whangārei District Council wastewater and storm water operations manager Andy Keith said people have fed poison in to the system a few times this year, upsetting it and killing off lots of beneficial bacteria that digest waste and help to clean up after people.

"If people really understood how hard these little guys work for us all and how vulnerable they are when all they are trying to do is clean things up, I am sure they would be much kinder.

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"Our message this summer is 'If you really care about the environment and the health of the harbour, you need to care for these microbes too and take care not to poison them'," Keith said.

"When they are poisoned they stop digesting waste properly. That makes it harder for us to clean the wastewater."
In recent years during the Christmas/New Year period the treatment plant has experienced problems where the beneficial bacteria which are vital to the treatment process have been killed off by unauthorised discharges of toxic materials such as paint solvent, detergent and disinfectant into the system.

"When this type of problem occurs the treatment plant has difficulty in treating the incoming wastewater. While all wastewater is still treated by UV to destroy harmful pathogens, when treatment is reduced this ultimately has an effect on our harbour as more nutrients are released into the water. In addition, some substances are unable to be removed during the treatment process and eventually end up in our waterways and harbour," Keith said.

"Other impacts include increases in odours from the plant and resource consent compliance issues, along with costs for remediation."

He is asking businesses or households having a clean-up before or during the holiday season to remember not to dispose of toxic chemicals down the drain.

Hazardous chemicals can be taken to Resort on Kioreroa Rd or, for large quantities, people can contact the council on 09 4304200 and speak to the pollution prevention officer to arrange collection.

"These must be disposed of in the approved manner. We'd like to remind the community that under the Wastewater Bylaw 2014 the discharge of any prohibited material is an offence and is liable to prosecution under the Local Government Act 2002."