Pukekohe Wastewater Treatment Plant

Advanced bioreactor technology helps us to build better, not bigger.

Completed in 2022, the Pukekohe Wastewater Treatment Plant is one of the most advanced facilities of its type in the country. Built through an integrated joint venture, the plant was described as “industry transforming” by Civil Contractors New Zealand (CCNZ) and recognised with a Highly Commended award at the CCNZ Hirepool Construction Excellence Awards 2021.

Our work

Accommodates complex resource consent requirements, including working in a live operational environment, limited construction space and an accelerated timeline to complete the first phase of the upgrade.

Contract split into two separable portions to effectively transition from the existing plant to the upgraded plan and included the construction, commissioning and handover of:

• New inlet works
• New activated sludge reactor
• Membrane bioreactor
• New ultra-violet disinfection system
• Retrofit of existing reactors

Stages 3 through 5 (separable portion B) include the retrofitting of “two existing sludge bioreactors  to create two new activated sludge reactors.

Separable portion A was successfully delivered in April 2021.

Sustainable Outcomes

This project was made possible by close collaboration between the client, iwi and kaitiaki (custodian) partners, consultants, and the project alliance team. Working together, we adapted plans to acknowledge the ecological, cultural and historical significance of Waikato te Awa (Waikato River), moving beyond simply future-proofing the plant, and instead addressing the wider issue of protecting and restoring the Waikato.

One of the most noticeable environmental outcomes from this collaborative effort was the cleaning of the Parker Lane Stream. Swapping the wastewater treatment plant’s treatment mechanism allowed us to lower nitrogen and phosphorus in the discharge – to levels never before seen in NZ. The process is now so thorough that clean discharge into Parker Lane Stream has improved water quality.