Environment Waikato has traced the bacteria in the Waikato River to an unusual discharge from the dairy factory at Hautapu.
Resource Use Group Manager Harry Wilson said today he was confident that staff had identified a “significant point source discharge” which explained the high bacterial results downstream from Cambridge.
The bacterial contamination was coming unnoticed from a pipe which flows into the river more than 6.7 km from the dairy factory site. The pipe carries low strength wastewater from a silo, which comes from sterile food processes and is not open to the air. It is thought the contaminated discharges could have been occurring irregularly for more than a year.
“The company has immediately stopped discharging and fixed the problem. They were completely unaware of it, as the discharge was never contemplated to contain any bacteria. This is an extremely unusual occurrence and could not have been anticipated.”
He said the discharge was not sewage, but contained microbial contamination. The resource consent for this discharge does not authorise the discharge of bacteria. It constituted an unauthorised discharge and there was potential for legal action to be taken.
The incident would be investigated further and reported to the Council’s Regulatory Committee meeting.
“We don’t know how it happened at this stage and it was completely unexpected. We are waiting for a full report for the Council and will continue to monitor the river extensively for the next month to ensure the situation returns to normal.”
He said it was extremely difficult to detect intermittent discharges of this type.
“We’re pleased to find the source. Water quality is extremely important to us, which is why we pulled out all the stops to identify the source and will continue to work on reducing discharges from both rural and urban sites. This incident has taken a great deal of time and resources, and we need the public to be vigilant in reporting discharges too.”