Hamilton Water Treatment Plant (New Zealand)

The Hamilton City Council in New Zealand wanted a world-class Water Treatment Station that met the city's water needs and exceeded or met New Zealand Drinking Water Standards at the lowest whole-of-life cost.

The original Hamilton Water Treatment Station (WTS) was a conventional clarification and filtration plant with a nominal capacity of 80 ML/d. The WTS drew water from the Waikato River and, in recent years, the water has shown increasing levels of unpleasant taste and odour as river algal levels increased. Cyanotoxins levels above detectable levels have also been found.

Hamilton City Council commissioned GHD to produce a 20-year strategy plan for the WTS.

The plan evaluated a range of upgrade options for both capacity and treatment performance. Technology options included granular activated carbon (GAC), ozonation, membranes and ultraviolet (UV) disinfection. The preferred approach was to provide additional processes to the existing plant comprising GAC filters plus UV disinfection.

This approach had an added benefit in that it allowed the existing plant to run faster to achieve an upgraded capacity of 106 ML/d without augmentation. Council subsequently appointed GHD to carry out the pre-design, detailed design, construction administration and commissioning for the upgrade. The work included procurement of the UV system and GAC media. The project also involved a total re-design and upgrade of the existing controls system, which was challenging on a key operating facility.

GHD’s scope included the following:

• Strategy development  
• Technical and commercial upgrade options study 
• Provided concepts preliminary design and costing
• Provided detailed design
• Compiled tender documentation and conducted tender evaluations
• Contract administration and site services
• Process commissioning and performance testing
• Operations and maintenance manuals

The upgrade included the following key elements (additional and modification):

• UV disinfection
• GAC filters
• Relift pump station
• Improved washwater handling
• Upgraded power supply
• UV/GAC and services buildings 
• Automation and controls upgrade

GHD met the council's needs and cost constraints. The Hamilton WTS is the largest GAC plant in New Zealand and also the largest UV disinfection facility in Australasia.

GHD brought skills and experience to the project and provided a multi-disciplinary consulting team that completed all the design, construction and commissioning phases. Working in partnership with the client’s team, GHD was able to fully meet operational requirements and minimise disruption to operations during the construction and commissioning phases.