The Hawke's Bay Regional Council could be varying the consent limit for wastewater treatment plants so the Waipukurau plant meets compliance parameters.

The Central Hawke's Bay District Council has applied for a variation in the plant's consent so it reflects that the treated water is having no effect on the Tukituki River.

The plant, which underwent a renovation last year after being served abatement notices from the regional council, only met five of its six parameters due to its ammonia levels.

These parameters measure the quality of wastewater treatment and are set by the regional council in the resource consents for each plant.


The amount of ammonia discharged from the treatment plant at Waipukarau exceeded the consent limit, but it was "well below" the limits set by the Board of Inquiry during the Tukituki Plan Change 6 process for ammonia levels in the river.

This will also mean the council is treated the same as all others who discharge into the river.

Technical services manager Steve Thrush said they had recognised they were having trouble meeting the levels in the consent.

"One way to remedy that was to put in a new pond to help the process but that would have cost about $200,000."

He said as the discharge was not having an effect on the river, varying the consent seemed the better option.

Council has been monitoring the river quality since 2008.

The results from this show that this level of ammonia in the river easily meets the Board of Inquiry limits, and is so low it is usually not detectable in the river.

The CHB council's other plants, which serve the towns of Otane, Waipawa, Takapau, Porangahau and Te Paerahi, met all parameters.

All treatment plants were operating as expected and the receiving environments were not being compromised by these discharges.

In January 2015 regional council served abatement notices on the CHB District Council requiring it to take action to improve the quality of the discharge of wastewater from both the Waipukurau and Waipawa treatment plants.

By August the regional council reported positive signs of improvement.