Major improvements to the management of wastewater treatment in the Wakatipu Basin will begin this year with construction of Queenstown Lakes District Council’s “Project Shotover” commencing.

The Council has awarded Downer New Zealand a $23.6 million contract for Stage One of the Project Shotover upgrade. It involves the design, build and five years of operation of a new wastewater plant at the existing site downstream from the Shotover Bridge.

The plant is due to be operational by December 2016. It will deliver higher standards of sewage treatment for Queenstown, Arrowtown, Frankton, Quail Rise, Arthur’s Point, Lake Hayes and Shotover Country.

The upgrade will bring environmental benefits including a significant reduction in the amount of nitrate and ammonia being discharged into the Shotover River; less algal growth downstream; less potential for odour and an overall healthier river environment due to a reduction in oxygen demand.

QLDC’s General Manager of Infrastructure, Peter Hansby, said that by the time the three-stage upgrade was complete, the Council would have moved to a modern and totally land-based effluent discharge system.

“Population growth in our District, coupled with the universal desire to maintain the high quality of our natural environment, means that our infrastructure increasingly needs to perform to a higher standard. This project is a significant investment by the Council to increase the capacity and quality of our sewage treatment at Shotover to meet our current and future needs.

“It also marks the start of a progressive shift away from discharges to water to a land-based system. This will provide much better environmental outcomes in line with the standards set by Otago Regional Council, and the expectations of our community.”

The new plant will treat 63% of the current effluent flow, with the remaining 37% continuing to be processed through the existing three-pond treatment system. The output from both treatment processes will then pass through an ultra-violet disinfection system, to kill bacteria and viruses, before being discharged to the Shotover River.

Stage Two of the upgrade will see the construction of a land dispersal field further down the Shotover delta, which will be taking the whole output of the Shotover treatment plant by the end of 2022.

Stage Three provides for the construction of additional treatment reactors on the same site and the retiring of the pond-system.  This will occur between 2025 and 2031.