Any reluctance to prosecute Hamilton City Council for repeated wastewater spills into the Waikato River risks creating the perception of a double standard, rural advocates have warned.
The comments by Waikato Federated Farmers president Chris Lewis came after the city council confirmed up to 800 cubic metres of untreated wastewater was discharged into the Waikato River last week.
The spill came from the Pukete wastewater treatment plant and occurred during two days of heavy rain.
The intense water flow compromised the plant's three inlet screens, causing untreated wastewater to be discharged into the river.
Waikato Regional Council spokesman Stephen Ward said regional council staff were notified of the incident and visited the plant last week.
The regional council had requested a full incident report from city council staff and expected to receive it in one or two weeks.
In 2012, Hamilton City Council was convicted, discharged and ordered to spend $37,500 on river plantings and fencing after discharging 90,000 litres of partially treated sewage into the Waikato River during an incident in July 2011.
That incident was caused by a mechanical failure, alarm settings and an overflow pipe blockage at the treatment plant.
The regional council launched a prosecution and the city council pleaded guilty to a charge of discharging contaminants into the river.
Ward said initial information from the city council suggested the latest incident was primarily the result of the very wet weather.
"We'll be checking all the details to confirm compliance has been achieved with their consents," Ward said.
"As always, the council will be assessing that information and making any subsequent necessary inquiries in a fair and even-handed manner."
But Lewis said repeated spills from the plant pointed to ongoing system failures.
"Farmers abide by tough environmental regulations and all we wish for is a level playing field," he said.
"It's hard to comment on individual cases without knowing the ins and outs. But if the latest spill at the plant is as bad as I've been told then it would be perceived as a double standard by farmers if the regional council decided not to prosecute the city council."
Hamilton City Council's city infrastructure general manager Chris Allen said the treatment plant received 139,800 cubic metres of wastewater during last week's heavy rainfall - the highest volume on record.
The average daily flow is 45,000 cubic metres a day.
"The incident that occurred at the plant last week was unusual and a result of a significant rain event," Allen said.
"Staff responded quickly, implementing contingency measures to minimise the volume of untreated wastewater discharged."
Affected river users were advised.
Allen said there were several programmes under way to protect against wastewater overflow events.
In 2011, a hydraulic failure at the Pukete plant caused up to 4000 cubic metres of untreated wastewater to enter the river.
On that occasion, the regional council opted not to prosecute the city council after concluding a statutory defence under the Resource Management Act was available for the discharge.
The RMA provides statutory defences against prosecution in certain circumstances, such as where a discharge occurs from an unforeseen mechanical failure.
Meanwhile, representatives from Waikato District Council appeared in Hamilton District Court earlier this month after 5000 cubic metres of partially treated sewage overflowed into the Raglan Harbour.
Four council staff have since left the organisation following the spill in June last year. firstname.lastname@example.org
- Waikato Times