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Published: 2009-11-27 00:00:00

An Environment Waikato hearing committee has granted new resource consents to Matamata-Piako District Council (MPDC), allowing the operation of an upgraded wastewater treatment plant at Morrinsville for another 15 years.

The committee - comprising commissioner Rob van Voorthuysen and EW councillor Simon Friar - was satisfied the consent conditions imposed meant that an upgraded plant at the site could operate in an environmentally sustainable way and would reduce the effects of treated wastewater discharges on the Piako River system.

Commenting on the decision, EW resource use programme manager Hugh Keane said he was pleased that MPDC and the regional council had been able to agree before the hearing on what was required for the plant to help protect the health of the river.

"Territorial authorities have an obligation to run their wastewater treatment plants in compliance with their resource consents to ensure the environment is protected, particularly waterways. MPDC is in the process of a major upgrade of their community wastewater facilities to make sure they are fully compliant and adequately sized for projected community growth - and this decision from the hearing committee requires MPDC to operate the Morrinsville plant more effectively," said Mr Keane.

The committee’s report also commented on the co-operation between MPDC and EW staff in future plant operating standards and monitoring requirements. "We note that by the conclusion of the proceedings there was agreement in large part between the applicant and the reporting officers regarding the wording of the recommended conditions."

The plant currently receives sewage from Morrinsville and Rukumoana communities, as well as wastewater from local industries including Fonterra’s Morrinsville factory and Greenlea Premier Meats.

The committee’s report noted that unauthorised discharges of wastewater into the Piako River had been occurring intermittently from a former oxidation pond although this discharge had been largely rectified since February this year except during times of high rainfall.

It said MPDC planned a further significant upgrade of the plant by the end of 2011 to improve its capacity and performance. This would include a cessation of any discharges from the former oxidation pond except during extreme rainfall events when such spills would be quickly assimilated by high river flows.

The committee accepted the environmental effects of any discharges from the former oxidation pond between now and the end of 2011 "will be less than minor". Fonterra had recently commissioned a wastewater pre-treatment system at its Morrinsville factory and the committee heard this is now reducing contaminant loads from the factory to the wastewater plant.

At the hearing the Department of Conservation raised concerns for nitrogen and phosphorous from the plant to increase nutrient loadings in the Piako River to a point where this could impact upon ecosystems of the Kopuatai and Firth Of Thames wetlands. But the committee noted evidence that the plant contributed only about one per cent and three per cent respectively of nitrogen and phosphorous inputs to the Piako River catchment and this could "hardly be deemed a significant adverse effect".

However, acknowledging the submission by Fish and Game New Zealand, the committee considered it was appropriate that macroinvertebrate surveys be included in river monitoring requirements, given that it was generally accepted by parties that this faunal group had been impacted by historical discharges from the plant.

Also, the committee determined that the upgraded plant at Morrinsville should operate under more stringent resource consents requirements, including the daily monitoring of wastewater volumes and more expanded annual reporting of performance.