The Times of India   07.08.2012

650km water pipes changed, twice as much still to go

CHENNAI: Finally, waking up to the threat of water contamination in the city, Metrowater has started replacing pipelines. More than 2,300km of pipelines that criss-cross the city were laid in the mid 1960s. Now, many of them may have corroded, leading to seepage of sewage and other impurities into the pipes.

Public health experts say this is a crucial step in preventing waterborne diseases. Metrowater has got Rs60 crore under the Jawaharlal Nehru National Urban Renewal Mission (JNNURM) to replace all the drinking and sewerage water pipelines within the older city limit.

The department had identified'more than 2,000km of pipelines along 15,000 roads. About 650km of pipelines running under areas such as Guindy, Virugambakkam, T Nagar, Saidapet, Choolai, Royapuram, KK Nagar and Villivakkam have been replaced with new ductile iron and mild steel pipes. "Most of the pipelines in the old areas were of cast iron, which rust over time. We will replace the old pipes by December-end," said a Metrowater official.

The organization has been facing problems clearing sewerage and supplying drinking water. The city has around five lakh water connections. Leaky pipelines are the main cause of water contamination. "Only if there are leaks do sewage water seep in. The liquid also overflows on the road only when the links are weak, and not able to withstand pressure," said former assistant city health officer Dr Damodaran Reddy.

Sewage gets mixed with the drinking water, when residents try to draw water after the supply or pumping hours. Since there is no water in the pipe, air pressure starts sucking in liquid from the surroundings through the holes on the pipe. This is what had happened in the Osankulam slum board tenements in Chetpet, Kodungaiyur and Kolathur where the residents were taken ill two weeks back.

Health officers say water contamination happens frequently during monsoon, which is why Metrowater increases the chlorine content in water by five times. Experts also feel that having a common enclosures for garbage collection in neighbourhoods could have also aggravated the problem.