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Customer: Hamilton City Council (HCC) Contract: Construct only Location: Hamilton, New Zealand   |
Fast Facts:
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Hamilton City Council is delivering a critical upgrade to the Pukete Wastewater Treatment Plant to meet growing demand and replace ageing infrastructure.
We were awarded the contract to build a new, larger inlet structure to replace the existing facility, which is at capacity, in July 2025.
The new inlet facility will increase capacity, improve reliability, and enable future stages of a $250M long-term development programme.
Major components of the work scope include:
- Demolition and Site Preparation: Removal of existing crib wall, redundant inlet stubs, and sections of DN1600 interceptors; excavation and ground improvement to the founding level.
- Construction methodology includes staged excavation, installation of sheet piles (temporary), mobilisation of heavy plant, and phased commissioning.
- Interceptor pipeline installation: DN1600 GRP/PE pipelines will be installed using the pneumatic bung isolation method:
- Inflatable pipe plugs are inserted and inflated to temporarily seal sections of live pipelines, allowing safe cut-ins and tie-ins without full plant shutdown.
- This method minimises operational disruption and mitigates the risk of uncontrolled flows during critical tie-in works.
- Sheet piling for interceptor cutovers using RG19 rig for precision
- Constructing a Motor Control Centre (MCC) Building: to house electrical control equipment, switchboards, and automation hardware for process control.
- Building new odour control covers over channels to contain foul air and integrate with ducting to the Bio-Trickling Filter.
- A Mechanically Stabilised Earth (MSE) wall (approx. 150m long, 1-2m high) built using the StoneStrong gravity block system for speed and durability. The team will reuse material excavated from the site as backfill.
- Commissioning: Pre-commissioning, cold and hot commissioning, followed by a 4-week trial period with split flows between old and new inlet structures.
The Pukete Wastewater Treatment Plant was constructed in 1975 and underwent an upgrade in 2002 to provide secondary and tertiary treatment. The upgrade to the plant will increase capacity and enable growth for the next 30 years.
Social outcomes from the project will focus on giving preference to local suppliers and hiring the workforce from the local community, as well as introducing sustainability initiatives, such as hybrid generators, to lower emissions.
Main construction commenced in September 2025 and is scheduled for completion in June 2027.
The 3D model below shows the planned construction and the existing plant in pale yellow. 
