Ngaruawahia Water Treatment Plant Upgrade

Waikato District Council
Harrison Grierson Consultants Ltd.

Project Scope

This Project involved the upgrade of the existing Water Treatment Plant in Ngaruawahia. The plant was kept on line during the upgrade, with only planned shut downs for tie ins.

The upgrade was required to increase the treated water throughput of the plant to 4.5MLD as well as meeting compliance guidelines set by the Drinking Water Standards of New Zealand.  Works included:

  • Construction of a new flocculation tower

  • Improved storage and new dosing facilities for all chemicals.

  • Improved coagulation/flocculation facilities to improve WTP performance.

  • Increased capacity from the clarified water pumps by increasing the motor size from 30kW to 37kW.

  • Removal of the existing filter aeration tray.

  • Installation of a new filter inlet weir box to control the flow split to the three filter inlets.

  • New filter backwash, washout, outlet and filter to waste pipework. The pipework included the supply and installation of a number of instruments and control valves.

  • New PLCs, MCCs and electrical wiring for the both main plant building and filter area.

    The scope and timeframe of the project was increased mid project to include the supply and installation of new in tank filtration systems.