Modern wastewater treatment for a growing Cambridge

Supporting a rapidly growing community, the Cambridge Wastewater Treatment Plant upgrade marks a significant step forward for both Cambridge and the Waikato River. With the population projected to increase from 20,000 to 50,000, the project strengthens environmental protection and builds long-term resilience. We supported Waipā District Council as technical advisor and lead consultant throughout the programme.

From 2021 to 2026, we delivered investigations, option assessments, detailed design, procurement support, and construction and commissioning advice. Working closely with mana whenua and Council, we developed an advanced membrane bioreactor biological nutrient removal facility that meets some of Aotearoa New Zealand’s highest environmental standards. 

The upgraded plant responds to population growth, rising environmental expectations, and the need to protect the Waikato River, a taonga of deep cultural significance. As lead designer, we integrated geotechnical, process, civil, mechanical, electrical, and structural engineering to meet strict nutrient, odour, and noise requirements, while embedding sustainability and safety in design.

A key feature is the advanced membrane bioreactor (MBR) system and enhanced disinfection processes, delivering a significant improvement on the former lagoon-based treatment. Treated water is discharged through a culturally guided outfall developed alongside mana whenua, helping restore the mauri of the water before it returns to the river.

Using digital design tools and advanced modelling, we improved coordination and reduced delivery risk. Early collaboration with the onstruction team strengthened buildability and value for money, while structured governance and transparent risk management supported steady progress despite complex ground conditions and site constraints.

The result is one of New Zealand’s most advanced municipal MBR reatment facilities, supporting Cambridge’s growth while safeguarding the Waikato River for generations to come.