Environment Waikato has turned down an application from Waitomo District Council to change its resource consent conditions for Te Kuiti’s sewage treatment plant.
The District Council had applied to remove a condition requiring it to install a wetland stage in the wastewater treatment process, and remove a requirement for annual reporting on land based disposal options. Five submissions were receive from the community including Tokanganui A Noho, Regional Management Council, Maraeroa C Incorporation, Rereahu Regional Management Committee, Waikato District Health Board and Fish and Game New Zealand.
The District Council investigated options for both wetlands and land based disposal and decided that they no longer wished to install a wetland. It considered further investigation into land based disposal was not required as the cost to the community of further upgrades was considered significant.
Chief Engineer Andrew Dixon said an upgrade to the treatment plant had resulted in a considerable improvement in quality of treated wastewater from the plant, but in the last 12 months the discharge had not met consent conditions for ammonia, suspended solids and phosphorus.
The District Council was to initiate a performance review of the plant to determine why consent conditions were not being fully met. The discharge was having a detectable impact on the Mangaokewa Stream in monitoring results taken upstream and downstream of the discharge.
He said wetlands did not typically remove nutrients from wastewater, even with harvesting of reeds, nor did they remove significant amounts of ammonia. Properly designed wetlands could remove bacteria and viruses, however adequate hydraulic retention time was required, and in some cases wildfowl attracted to wetlands could increase faecal pollutants.
Mr Dixon acknowledged that the direct discharge of treated wastewater to water was culturally unacceptable and the proposed wetland would have addressed some of those concerns. The Council would further investigate alternative disposal schemes that might be acceptable to the community.
Environment Waikato Consultant Tina Warnock said a number of conditions were now compromised by ongoing non-compliances and the District Council requesting their removal. The applicant had not offered any mitigation for their proposal to remove conditions.
The Hearing Committee acknowledged that the discharge was a better quality than before the upgrade but it wished to see the original proposal completed. It was concerned about ongoing non-compliances with discharge standards after the upgrade, and that the discharge quality appeared to continue to be affected by industrial waste.
The Committee was concerned that the applicant had offered no mitigation for the effects of the abandonment of the wetland treatment stage, only more consultation. It supported the proposal to discuss other non-land based disposal options with the community while working towards consent renewal.