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DECEMBER 2010

Harrison Grierson have undertaken the design and commissioning of an upgrade to the chlorine disinfection system at the Huia Water Treatment Plant - a plant which supplies 25% of Auckland's water requirements. It had been determined that the existing liquid/gas mixed chlorination system was inadequate to meet peak demand and didn't meet the the requirements of AS 2927:2001 The Storage and Handling of Liquified Chlorine Gas. A more robust system of gas dosing of chlorine was devised and the commissioning of a new, more reliable process was completed in December 2010.

The new chlorination system implements industry best practice to introduce chlorine gas by an automated process involving two 'trains' which can operate independently and act as a back-up to one another. This ensures there are no single points of failure while reducing the frequency of required chlorine deliveries to site and plays a large part in achieving the important goal of uninterrupted flows of safe drinking water now and into the future for Auckland City.