Gore District Council to construct new $61m wastewater treatment plant

Tuesday, 3 November 2020

The Gore District Council will build a new multi-million dollar wastewater plant at the site of its current plant.

The Gore District Council will build a new multi-million dollar biological nutrient removal treatment plant to treat wastewater before discharging it to the Mataura River.

The plan will be done in three stages and completed in 2050 and will cost between $46 to $61 million.

The council will need funding partners to carry out the project. The treatment process includes the removal of nitrogen, which encompasses nitrate and ammonia.

Council chief executive Steve Parry said the project was daunting, and the council was expecting people to feel shocked about the figures involved, but it was left with no choice but to upgrade how it treated and disposed of wastewater.

“The world has moved on in regard with what it accepts with respect to discharges to water,’’ he said.

* Gore council blames glove for discharge to river

* Second discharge to Mataura River under investigation

* Debris on Mataura River banks 'disgusting'

The Gore District Council’s oxidation ponds will be repurposed when a new wastewater treatment plant is completed in 2050.

“The public at large wants to see waterways in better shape. It’s not just farmers, it’s councils as well that have to step up and essentially it’s beyond our control.’’

The project will allow the repurposing of the council’s current oxidation ponds to provide enhancement of the treated wastewater prior to its discharge.

Parry said the process to choose a BNR plant over other methods of treatment had been a lengthy one.

It assessed 18 different options to upgrade the two plants during the past two years. It shortlisted three options and came up with the best practicable option for the Gore and Mataura plants.

There was ‘’no question’’ that the council would require assistance from the Government to fund the project, he said.

At Gore plant, a BNR plant will be built by 2030 to treat trade waste, which would cost between $10 and $12 million.

The existing oxidation ponds will be desludged and the existing Actiflo treatment system will be optimised.

Stage two of the project, to be completed by 2040, will cost between $27 million and $37 million and include the construction of a second BNR treatment plant to treat 50 per cent of Gore’s domestic wastewater and trade water from minor industries. The remaining 50 per cent of Gore domestic wastewater will continue to be treated through the existing ponds.

The third stage, to be completed by 2050, will include the expansion of the existing plant and repurposing the oxidation ponds.

Mataura’s wastewater treatment plant will also receive an upgrade, although the council says it is operating well and when considering the small population of the town, the cost of upgrading to a full mechanical treatment plant or disposal to land is very high and will provide limited environmental benefit.

An estimated $1.6 million and $2.1 million will be spent to expand the existing wetlands system and other improvements to optimise the existing treatment plant at the township.

The council is currently working on lodging applications with Environment Southland to renew discharge resource consents for the Gore and Mataura wastewater treatment plants. It has consent to discharge treated wastewater and stormwater to the Mataura River from the Gore oxidation pond and the Mataura oxidation pond.

These discharges are consented for terms expiring in May 2021 at Mataura and December 2023 at Gore.

The council will host a Pop Up Community Session at the intersection of Salford Street and Grasslands Road, from 4.00pm to 6.00pm on November 11. More information is available from www.lets.talk.goredc.govt.nz