Council discharges treated wastewater into Opihi River

The Timaru District Council discharged 600 cubic metres of treated oxidation pond effluent into the Opihi River yesterday.

The discharge of the treated wastewater was a necessary short-term solution as the Pleasant Point oxidation pond was at capacity, according to the Timaru District Council.

But Environment Canterbury is not happy.

ECan director of resource management Kim Drummond said the district council sought permission for the discharge earlier in the week.

"Our position was that no discharge should occur, and if it did then it would be treated as a breach of Resource Management Act rules. We advised the Timaru District Council of this.

"Environment Canterbury takes this very seriously and will now start an investigation."

However, council drainage and water manager Grant Hall said groundwater had infiltrated the sewer system but the discharge, just upstream of Butlers Crossing, was fairly diluted.

"It is treated wastewater, not raw sewage," Hall said.

Levels of dissolved oxygen were being monitored. Pets were unlikely to be affected but notices were installed on site to warn the public not to gather food or swim in the area. Other users such as local landowners, Arowhenua and Fish and Game had also been notified.

The need to discharge into the river occurs about once a year, Hall said.

It had only become an issue in the last few years but he is not sure if it is earthquake-related.

"We had not experienced this infill to the sewers like this before. It's not ideal."

The council was working on rectifying the problem and looking at replacing and realigning cracked pipes, though the extent of repair required was not yet known.

The Timaru Herald