S. Ramesh

It works on the basis of photosynthesis

Civic body finds it difficult to maintain normal chlorine level Pre and post chlorination process can be stopped

SALEM: Faced with the problems of `fluctuating chlorine' levels in the drinking water supply and to ensure consistency, the Salem Corporation has decided to adopt the `silver ionisation' process for the first time on trial basis.

Despite the pre-chlorination process taken up at the water treatment plants in Nangavalli, near Mettur, and the post-chlorination at the overhead water tanks, the Corporation is finding it difficult to maintain the normal chlorine level of 0.22 ppm (parts per million) in the water till the tail end of its water distribution network.

"During the chlorination process, health workers add 4 gm of bleaching powder for every 1,000 litres of water. But this manual process is not accurate. As a result, at several distribution points, particularly in the tail end of the distribution network, the chlorine level differs from 0.10 to 0.20 ppm," city water managers say.

Hence, the Corporation has proposed in its Budget report for the year 2006-07 to adopt the silver ionisation process. "This innovative technology, which works on the basis of photosynthesis reaction, has proved effective in killing the bacteria and other organisms in water that may cause infection. According to the proposal, the process will be implemented at all the overhead water tanks in the city in a phased manner," Corporation officials say.

Initially, a few tanks will be selected after a detailed analysis to introduce the silver ionisation process before extending it to all the tanks in the city. The civic administration will stop the manual pre and post chlorination processes once this technology is installed.

The Corporation supplies 64 MLD a day to its 7.53 lakh citizens. A few Corporations have already executed this technology on a trial and error basis and its results are positive, Corporation officials said.

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