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UV may see end to chlorine at city's largest pump station

An above ground well head.

Update: Friday 17 August 2018

A $2 million investment in ultra-violet (UV) light disinfection could bring an end to chlorination at the city’s largest water supply pump station.

Staff have recommended UV light disinfection at the water supply pump station at the south end of Colombo Street. A report outlining plans will be considered by elected members on Thursday for approval.

The station - known as Main Pumps - takes water from six wells and feeds about 11 per cent of the central zone.

The central zone provides water to about 185,000 people – just over half the city’s population.

You can read more detail about the proposal on Newsline.

Council looking into water cylinder failures issue

Council staff,  along with local and national manufacturers, are investigating issues around failures of hot water cylinders.

Industry representatives and Council staff met today to gain a better understanding of the issues regarding cylinder-related failures, historically and more recently.

We have all agreed that the next step is to quantify the problem and to investigate why these issues are occurring. 

Council staff will be looking at other water supplies around the country to see if there have been any similar issues and if there are learnings we can draw on.

Manufacturers will also be looking to get more detailed information about which areas are affected and to identify specific cylinder types that have failed.

The rate of failure varies across the country depending on the water chemistry of a particular supply and the design of the cylinder. Some groundwater supplies that have a low pH (below 7.0) are known for having a higher failure rate. The Christchurch average from tests taken before temporary chlorination is 7.8.

Keep up with what's happening

Stay up to date with our rolling blog on Newsline.

If you have any questions, drop us a line at watersupply@ccc.govt.nz