Environment Waikato has granted an application from Waikato By-Products Limited to continue operations at the Tuakau rendering plant – but only for another three years.
The company had applied to renew consents to take water from the Waikato River, discharge treated wastewater to the river and odour contaminants to air. It proposed mitigation measures to reduce odour emissions and improve wastewater discharge quality. Seventeen submissions were lodged from Waikato Raupatu Trustee Company, community organisations and neighbours.
The company said the plant had significant benefit to the local and regional community, and improvements to the site could be made. Consultants for the company with expertise in water and air quality said the effects of discharges were less than minor on river ecology, and site improvements since the late 1990s had significantly reduced odours.
The company’s consultants said that converting a treatment pond to an aerated system and reducing organic loads to the wastewater treatment system would significantly reduce odours. A wastewater chemist said some proposed discharge standards were too strict and unachievable with the present wastewater treatment plant, imposing unjustifiable costs on the company.
Submitters expressed concerns about odours, the health and safety of rowers and the company’s poor compliance record. One said the Waikato River was being used as a drain by various dischargers and the proposed increase in discharge loads to the river was not consistent with Council policies. The Onewhero-Tuakau Community Board and Community Liaison Group were concerned about poor compliance and monitoring.
Environment Waikato staff said the effect of odour on neighbours was the most significant environmental effect and odour levels should be significantly reduced. They recommended that all anaerobic ponds should be covered with a synthetic cover.
Some neighbours considered themselves to be significantly affected by the odour. The company did not have a proven record of compliance, and the local community had concerns about future compliance. While significant efforts had been made to improve the treatment efficiency of the present wastewater treatment system, the company had not offered to improve the effluent quality further and had requested a lower treatment standard.
The Hearing Committee said that converting the first treatment pond should be completed within six months, as it was a major source of odour. The company must take active steps to ensure that an effective natural cover formed on the pond as soon as is possible, and was maintained. The Committee was concerned that the company had not provided evidence that the plant would be environmentally sustainable long-term.
A three year term would give the company time to commit sufficient resources to treat objectionable odour and prove to the community and Environment Waikato that it was an environmentally sustainable activity.
The company had made minimal effort since the 1996 hearing to accurately assess the effect of site odours and more formal and scientific surveys were needed. The company appeared unwilling to reduce the discharge loads further, which was out of line with the wishes of the wider community, iwi, the Regional Policy Statement and the efforts made by other point source dischargers in recent years, the Hearing Committee said.
While efforts had been made to improve effluent since 1997, the efforts were not sufficient to warrant a longer term than three years. This would give time to assess whether effluent quality could be improved. The company should provide $15,000 in mitigation each year for three years for the adverse environmental effects of the discharge on the river, directly related to the water quality or habitat of the lower Waikato River.
A 25 year term was granted for water take, with similar conditions to the existing consent.