Customer: Watercare Services Ltd

Contract: Construct Only

Location: Auckland, New Zealand




Water & Wastewater Solutions New Zealand & Pacific Islands

 Fast Facts

  • 3,950 m3 of concrete insitu
  • 447 tonnes of steel reinforcing
  • 404 precast concrete panels and beams
  • 4,120 m of underground pipework
  • 7,820 m of stainless-steel pipework above ground
  • 106,680 m of cabling including power, communication and instrument
  • Upgrade more than doubled the capacity of the current plant

Delivering another state-of-the-art wastewater treatment plant upgrade to Auckland

Watercare engaged McConnell Dowell (in joint venture) to upgrade the Pukekohe Wastewater Treatment Plant (WWTP) to support population growth in Franklin and improve the quality of the water discharge into the Waikato River.

The upgrade of the Pukekohe WWTP was completed on time and within budget while keeping the existing WWTP fully functioning. This new WWTP is one of the most advanced plants of its kind in the country, and has more than double the capacity of the plant, enabling it to cater for up to 60,000 people.

We converted the current reactors that clean the water into activated sludge reactors and constructed a third reactor, increasing the plant’s previous capacity. We also constructed a new Ultra-Violet disinfection system, which greatly improved the water quality being released into the Parker Lane stream and Waikato River.

The challenge

The project had to be delivered to a very tight construction programme due to the resource consent conditions. Watercare had a limited budget project for the project, requiring us to value engineer aggressively to win and deliver it.

WWTPs are highly complex projects combining major civil works with a significant mechanical build. With multiple work fronts, work at height and in confined spaces, in both greenfield and constrained brownfield environments adjacent to and within the Pukekohe WWTP, this project was challenging from a health and safety perspective.

The solution

We drew on our learnings from the award-winning Mangere BNR project to fast-track the construction programme and value-engineer the project to bring it within budget.

Our experience on Mangere BNR (the largest mechanical installation undertaken in New Zealand in the last 15 years) provides the ideal grounding to manage the complex mechanical works and commissioning for Pukekohe.

We implemented some of the health and safety initiatives used successfully on Mangere BNR to deliver the project safely, including developing a strong safety culture, robust permitting procedures, and a thorough training and awareness programme to ensure all staff understand and strive to mitigate safety risks associated with working in this high hazard environment.

Innovation including using large diameter Polyethylene (PE) pipework rather than the specified fibreglass (FRP) pipe and knife gate valves instead of the valves specified, saved money and helped reduce the project’s carbon footprint.

Key to success

Many key members of the leadership team from Mangere BNR worked on the Pukekohe WWTP project, bringing with them a deep understanding of the challenges of building a high-spec wastewater treatment plant and the associated health and safety requirements.

Extensive engagement with Watercare, Te Taniwha o Waikato (a group of nine marae covering iwi and hapū in the Lower Waikato River) stakeholders and neighbours was integral to deliver this successful project.

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