Cambridge wastewater treatment plant
Image: Cambridge Wastewater Treatment Plant
Updates
December 2024
The construction of the new Cambridge Wastewater Treatment Plant is progressing smoothly and remains on track, with key milestones achieved in recent months.
Cambridge Wastewater Treatment Plant Build on Track, 9 December 2024
October 2024
The partnership Waipā District Council formed with iwi during the successful co-design of the plant, ensuring decisions were shared and the Waikato River’s wellbeing was prioritised, was the key to the project being singled out at the 2024 ACE awards.
The Kaitiaki Group, established by the council, won the Special Award in recognition of its commitment to collaborate, embracing indigenous knowledge, and honouring the principles of kaitiakitanga [guardianship] and Te Tiriti o Waitangi.
The Kaitiaki Group is made up of Ngāti Koroki Kahukura, Ngāti Hauā, Waikato-Tainui, Community Liaison Group, Waipā District Council, Waikato Regional Council, and consultants GHD.
The council established the group as the Cambridge Wastewater Treatment Plant Project sought a 35-year term for discharging treated wastewater into the Waikato River.
Cambridge Wastewater Treatment Plant wins special award, 25 October 2025
June 2024
A key milestone in the construction of Cambridge’s new state of the art wastewater treatment plant was achieved with treated effluent diverted to a new outfall structure for the first time.
Waipā Mayor Susan O’Regan, elected members, mana whenua representatives, the Kaitiaki Group, Waikato Regional Council, and a representative from the Waikato River Authority were all present to witness history being made as the treated wastewater meandered its way to the Waikato River over the new rock lined structure.
The structure on the bank of the Waikato River replaces the rapid infiltration beds system. Construction started in December 2023, with work underway until late 2026.
Cambridge wastewater treatment plant reaches another milestone, 5 June 2024
September 2023
A growing population, plus new environmental standards and other legal requirements mean a new wastewater treatment plant is needed for Cambridge. The new plant will also service Hautapu and Karāpiro Domain.
The new plant will meet very high environment standards, will take up less room on the site and will do everything possible to meet higher community aspirations for the health of the Waikato River.
In September 2023, Waikato Regional Council formally granted a 35-year consent for the new plant, following a five-year planning process.
35-year consent for new Cambridge wastewater plant, 28 September 2023
Image: Cambridge WWTP Site Location
Timeline
| Milestone | Completion Date |
| Enabling works | May 2024 |
| Outfall structure | April 2024 |
| UV Building | May 2024 |
| Stage Two commenced | June 2024 |
| Stage Two completed | March 2026 |
| Commissioning Underway | March 2026 |
| Site Transferred to new consent | No later than December 2026 |
| Wetlands and solar farm completed | September 2026 |
Waipā District Council has already let three large contracts, including to Spartan Construction, who are building the plant.
Construction began in late 2023 with the new outfall discharge being constructed and brought into service in early 2024.
The new plant will be up and running by 2026.
About Cambridge's wastewater treatment plant
What does the existing Cambridge wastewater treatment plant do?
The existing plant has been operating since the 1970’s. It receives, treats, and discharges wastewater from Cambridge and surrounding areas. This is critical to maintaining public health and minimising contamination of land and waterways.
The Cambridge plant is located Matos Segedin Drive to the west of Cambridge township, surrounded by the Waikato River to the north and farmland and industrial sites along other boundaries.
How does the existing plant operate?
The existing plant receives wastewater, treats it, and then discharges it to land before the treated water travels to the Waikato River as groundwater. While this form of treatment has been acceptable in the past, environmental standards are now higher. We also have higher aspirations and legal obligations to the health of the Waikato River.
Construction of a brand-new plant is in progress and the discharge from the old plant has been relocated to the new outlet structure. This outfall structure will be used by the new plant.
Is the current plant still operating safely?
Yes, absolutely. The Cambridge wastewater treatment plant has been operating under several resource consents, first granted in 1997. Over the past four years, we’ve been upgrading the plant to comply with changing operating conditions.
In December 2020, Council was granted a short-term resource consent to allow the plant to continue operating and discharging wastewater. A condition of the approval was that a resource consent for a new plant was lodged and that the new plant be operational by 1 Dec 2026.
The consent for the new plant was approved in 2023.
How will the new plant compare to the existing one?
We’re committed to meeting the highest possible standards when it comes to wastewater treatment. The new Cambridge plant will treat wastewater to a standard that is comparable to the best treatment plants in New Zealand. This will be done utilising Membrane Bioreactor (MBR) technology.
The new plant will also align with Te Ture Whaimana o te Awa o Waikato, the Vision and Strategy for the Waikato River and with Tai Tumu Tai Pari Tai Ao, the Waikato-Tainui Environmental Plan. These are both legal requirements.
It will comply fully with Waikato Regional Plans and any conditions laid down by the Waikato Regional Council while also considering matters of importance to tāngata whenua.
Will the new plant look different?
Yes! The new plant will look very different to the one that exists now in Matos Segedin Drive.
The existing Cambridge wastewater treatment facility is largely a pond system (including wetland ponds), requiring a very large area for it to operate.
The new plant will consist of buildings, tanks, and large concrete structures instead of the current pond-based system. It will occupy a smaller footprint – around one-third of the size of the existing plant. That means unused land on the site, which is not required for the new plant can, in the future, be remediated and put to better use.
The new plant will also include its own on-site solar farm, generating enough energy to power the plant during the day. It will also consider visual impact, noise and odour management plus meet the highest quality effluent standards. Biosolids produced by the plant will be taken off-site for re-use as compost via a third-party.
Image: New plant layout
How will water be discharged from the new plant?
Council undertook a thorough assessment to determine the best location and method of discharging highly treated wastewater from the new Cambridge plant.
Investigations identified that discharging via the current Rapid Infiltration Beds was not possible, because of groundwater, geotechnical, and construction risks presented by the site.
Following Kaitiaki Group advice, the discharge option chosen was a gabion wall/rip-rap (rock) structure on the bank of the Waikato River. Highly treated wastewater will flow down the structure before reaching the Waikato River. The discharge structure is located within the site itself.
Image - Treated wastewater outfall structure.
Media Releases
- Cambridge Wastewater Treatment Plant Build on Track, 9 December 2024
- Cambridge Wastewater Treatment Plant wins special award, 25 October 2025
- Cambridge wastewater treatment plant reaches another milestone, 5 June 2024
- 35-year consent for new Cambridge wastewater plant, 28 September 2023
- Council awards largest contract package, ever, 29 March 2023
