Environment Waikato is waiting to see the details of how Contact Energy is going to clean up its Waikato River discharges.
Contact announced an initiative this week to improve the quality of the water discharged into the Waikato River from its Wairakei geothermal plant. It said it had listened carefully to submissions to its resource consent renewal applications from river users and communities.
It intended to remove or reduce trace elements, including arsenic, found in separated geothermal bore water. The most likely options were water treatment and further outfield re-injection, where water was returned underground but away from the geothermal field.
Environment Waikato Resource Use Group Manager Harry Wilson said the Council supported the initiative, but the details were as yet unclear on how the contaminants would be reduced.
“Contact has already reduced the load of geothermal contaminants going into the river in recent years since it began re-injecting a portion of the fluid, but the separated geothermal water carries large loads of contaminants, including arsenic and boron, into the river.”
Submitters to the company’s consent application had put pressure on to reduce contamination discharging into the river.
“We are pleased Contact is making efforts to improve the discharge, but the details of how this will be done are not yet clear.”
He said that Environment Waikato and the Waikato Valley Authority before it had made it clear to Contact and its predecessors that the geothermal water discharge was a significant concern for Waikato River quality.
The current re-consenting process for the Wairakei discharges was the first time since the plant was built that the discharges would be subject to formal environmental scrutiny.