Illegal petrochemical dumping damages treatment plant
Friday, 23 August 2024
Wellington Water is following “a positive line of enquiry” over the illegal dumping of petrochemicals, which is costing Hutt Valley ratepayers hundreds of thousands of dollars.
Over the last 18 months there have been four instances of “large quantities of petrochemicals” detected in the Seaview Wastewater Treatment Plant.
Network manager Jeremy McKibbin said it was a major problem.
“The illegal disposal of petrochemicals has significant risks to the plant's safety, being highly flammable and potentially explosive. It also compromises the plant's performance, affecting the biological treatment process.”
The clean-up cost has been about $50,000 each time, a cost met by ratepayers from the two Hutt councils.
McKibbin said Wellington Water and the Hutt City Council were trying to find the culprit and have been alerting nearby businesses with a letter drop about the illegal activity.
“We are analysing sampling results to determine if it is industry specific and are following a positive line of enquiry with further CCTV inspections at manholes in the area.”
The contaminants are adding to the on-going odour issues and are a threat to the environment, McKibbin said.
“Petrochemicals are not totally extinguished during the treatment process and contaminants can enter the environment after leaving the plant.”
The illegal disposal of petrochemicals can lead to prosecution under Hutt City Council by-laws. The council can also block culprits’ access to discharge at gulley traps and manholes, and cancel consents.
Wellington Water recently posted on social media that it was having on-going problems at the plant.
“Our wastewater team have noticed petrochemicals such as oil, diesel, and other fuels being detected at the Seaview Wastewater Treatment Plant recently. You may not know this, but this has negative impacts on the plant, the environment, and the wider community.“
McKibbin says people should “never pour hazardous substances” into household or stormwater drains
“Paints (oil and water based) and thinners are toxic to aquatic life, and cause discolouration of streams. Make sure you read the instructions on the container label and clean and dispose of paints, thinners, and other hazardous substances responsibly.”
Although four large discharges had been recently detected, there were likely to have been others, he said.
“We are unsure about the overall number of contaminations in the past year. It is likely there has been more going undetected, and more frequently, but it is not always immediately noticeable if the quantities are small.”