Environment Waikato has granted resource consents for discharges from the Turangi Wastewater Treatment Plant.
Taupo District Council had applied to discharge treated domestic effluent from the plant to Hangarito Stream and South Taupo Wetland. Four submissions were received from the Department of Conservation, Genesis Power, Ngati Turangitukua and a resident.
The District Council wants to discharge up to 2100 cubic metres of treated sewage effluent from the plant at Awamate Rd into the Hangarito Stream and the South Taupo wetland, which is recognised as a wetland of national importance and meets Ramsar Convention criteria for a wetland of international significance.
As a result of the stringent consent conditions, the district council will need to construct a new state-of-the-art treatment plant to achieve the required effluent quality. The original plant was designed for a population of 8000 but an actual population of about 4000 meant the existing ponds were oversized and could produce excess algal growth.
The ponds were not effective in removing ammonia and phosphorous. The cost of re-developing on the current site is about $2 million while an alternative site would be at least $4.8 million with annual running costs 49 percent greater. The applicant proposes to carry out the physical works during next summer with commissioning early next year.
Scientific advisor to Taupo District Council Dr Brian Coffey told the hearing that effects on the wetland and Lake Taupo were likely to be no more than minor if the phosphorous load from the upgraded plant was limited.
Ngati Turangitukua representatives said they were deeply troubled by the effects of the plant and encroaching pollution and nutrient seepage into the lake, affecting food gathering.
In making its decision, the Committee acknowledged the upgrade had resulted from community concerns over the environmental performance of the existing plant. It could not take into account a possible stream diversion that would be the subject of a separate process. It also took into account initiatives to improve Lake Taupo water quality.
Performance standards would achieve a substantial reduction in the levels of nutrients and contaminants entering the Lake and the wetland, the Committee said. It could not support an alternative site, which may result in greater potential for contaminants to enter Lake Taupo.
Conditions were imposed to involve Ngati Turangitukua in development of the monitoring programme, site management plan, outlet design and plans to remediate unused treatment plant land after the new plant is built.
While there was significant capital investment for the community, a number of environmental uncertainties with the discharge raised questions over its long-term sustainability, it said. The consent was granted for 15 years so issues could be addressed.