26 March 2024:

Fulton Hogan’s Civil division’s expansion of Wanaka’s wastewater treatment plant has helped ease the region’s growing pains.

Involving heavy civil, mechanical, electrical and process works within live operations on one of Queenstown Lakes District Council (QLDC)’s critical water assets, the expanded plant is designed to meet 30 years of projected population growth in Wanaka, Albert Town and Luggate.

Civil helped build the original plant a decade ago. Now nearing capacity, QLDC commissioned Civil (including Fulton Hogan Civil Division’s new mechanical & electrical division) to upgrade the plant.

Project Manager Jonathon Ireland says it was critically important that existing operations continued at the plant during the upgrade.

“It was a huge effort by all with the upgrade, with some complex integration and tie-ins while keeping everything live and operational.”

The physical tie-ins and integration of the new plant required meticulous planning with QLDC and QLDC’s O&M Contractor, Veolia.

The onsite capacity is now 7,873m3 per day average flow, with 16,130m3 per day peak wet weather flow – more than double the previous.

Jonathon says his team managed the works without any major operational issues or loss of critical supply.

“A huge amount of planning and effort from all. The team really put on a show, demonstrating the full range of skills required on a complex multi-disciplined project like this. The proof is in the product we have handed over.”

He says the project was also deeply gratifying.

“We have helped double the capacity of the plant, enabling the local communities to safely process all their wastewater. This region now has enough resilience to manage forecast growth for at least the next 30 years.”

The project is also being used by QLDC as a pilot for carbon spend and waste management benchmarking, with carbon emissions measured across the project, including from subcontractors and suppliers. The data is being assessed against the original design’s desktop assumptions, enabling QLDC to use the numbers to benchmark future projects.

The project entailed:

• Significant power & utility relocation, diverting the existing high voltage power on-site
• Building a third SBR tank and second decant tank – approximately 60m long x 16m wide x 5m deep with 1,050m3 of in-situ 50MPa concrete
• A complete upgrade of the existing ancillary plant to integrate with the additional treatment train
• Relocating the existing UV treatment process with the addition of a third UV unit and tertiary filtration system
• Supplying, installing and commissioning all process mechanical and electrical equipment
• Expanding the existing disposal field with approximately 2,000m of feeder and irrigation distribution pipework
• Designing and building a new operator building for amenities and laboratory
• Complete upgrades to the sludge processing capacity.