City council convicted for wastewater discharge

Hamilton City Council has been convicted and fined $76,500 in respect of a discharge of wastewater into the environment over a period of nine days in October 2020.

The sentence released yesterday (Monday, 3 October) was imposed by District Court Judge Melinda Dickey after a prosecution was initiated by Waikato Regional Council, environmental regulator for the Waikato region.

“This is an unfortunate case,” said regional compliance manager Patrick Lynch. “Hamilton City Council maintains a very large wastewater network for the more than 160,000 residents and numerous businesses of Hamilton. By and large, they do that very well from a regulatory and environmental perspective. However, in this instance, they have dropped the ball, resulting in avoidable discharges of large volumes of contaminant into a tributary of the Te Awa O Katapaki Stream in Flagstaff.”

The Waikato River is approximately 1.9km from the point of discharge.

“Our investigation revealed that staff within Hamilton City Council were aware of the contaminated stream on 6 October 2020. They also knew it was likely the contamination had been occurring for some time,” Mr Lynch said.

“The source was found to be an overflow from the wastewater system into the stormwater system that then discharged into the tributary. Despite having that knowledge, through a series of communication failures within the city council, the discharge was not stopped until 12 October.”

A retrospective review of the city council’s own data management system indicated loss of wastewater into the environment as early as 4 October.

Wastewater comprises used water from domestic and commercial premises. Wastewater includes a range of potential contaminants of varying concentrations and sewage is a subset of wastewater that is contaminated with urine or faeces.

It is estimated that over the nine-day period, 1,272,000 litres of wastewater was lost into the environment. This is approximately half the volume of an Olympic size swimming pool.

“This is a very clear reminder to any company, or council, that manages large volumes of contaminant as part of their business. They must have fit for purpose infrastructure, manage that infrastructure well and ensure they take immediate steps to mitigate any discharges that occur into the environment.”