Millions spent on failing plants

New wastewater plants that dump treated sewage into the Tukituki River in Hawke’s Bay won’t work the way they are supposed to and the council that has spent $8.4 million on them is now in ‘‘confidential discussions’’ with their designers.

The new plants at Waipawa and Waipukurau use floating wetlands and were finished in 2013-14 at a cost of $6.4m. Central Hawke’s Bay District Council has spent a further $2m trying to get them to work better.

The plants have not been able to meet resource consent conditions for ammonia levels entering the river and have breached E coli levels several times with exceptionally high readings. In July the council pleaded guilty to exceeding resource consent conditions at the Waipawa plant and commissioned an independent review into the plants.

Initial findings of that review show neither plant is likely to meet consent conditions as both are failing to deal with ammonia levels.

In a statement this week the council said it was too early to say if it would need to build new plants.

The final review, by Wastewater Specialists Ltd, will be completed this month. This would cover the capacity of the present plants and potential solutions.

The plants were built by Waterclean Technologies and are still under warranty.

‘‘Council has entered into confidential discussions with Waterclean Technologies about this,’’ the statement said.

Mayor Alex Walker said her community had been ‘‘very patient with the ongoing issues’’ and ‘‘it is more than frustrating’’.

She said the wastewater discharge had improved vastly with the new plants with consent levels being met in most areas, including a 97 per cent reduction in the amount of phosphorous entering the river.

The issue of odour coming from the Waipukurau plant is believed to be un-related and is the subject of ongoing investigation and remediation.

Council chief executive Monique Davidson said the full report would provide a better picture of the issues and potential solutions but ‘‘we felt it prudent to advise residents and ratepayers of the initial findings so that they are aware of the gravity of the situation’’.

The Waipawa consent had allowed the council to discharge 4000 colony forming units (cfu) of the bacteria per 100 millilitres of wastewater.

This was exceeded in 2015 on November 5 and 19 and in 2016 on January 28, July 14, August 11 and September 22.

It was the September excess that resulted in the charge being laid in November last year.