Chlorine out, UV in at largest pump station

One of the city’s largest pump stations may be permanently free of chlorine by June.

The city council is expected to approve a $2.25 million ultra-violet light disinfection system for one of the city’s largest water supplies, Main Pumps station, at the south end of Colombo St.

“The advantages of UV treatment is there are no taste and odour effects – we think we could have it installed at Main Pumps within 10 to 12 months,’’ said city council water supply programme manager Helen Beaumont.

The station takes water from six wells and feeds about 11 per cent of the central zone, which provides water to about 185,000 people. The city council is investigating bringing in UV treatment at “a number” of pump stations around the city, which can’t be secured otherwise.

“We will not have a timeline for implementation until we have completed concept designs and estimated the costs for the plant required at each pump station,” Ms Beaumont said. A report is expected in October.

Ms Beaumont said the city council has sufficient funds to complete the work that has been scoped for this financial year.

“Further work needs to be done before we can provide the total costs for the longer term water supply improvement programme.”

It comes as 10 pump stations around the city, which feed more than a quarter of the water supply, have become chlorine-free this month.

The latest, Thompsons pump station, was stopped on Tuesday.

But Ms Beaumont said it would only be possible during low water demand, such as winter, so water conservation would be needed through summer.

Almost all of the city’s water supply was chlorinated in March after the city council voted for 12 months of chlorination, while unsecured well heads were repaired in January.

Ms Beaumont said the timeline was “challenging”, but it remains the target.