Coimbatore: Coimbatore corporation commissioner Katta Ravi Teja has directed officials to collect and test drinking water samples from the Pillur scheme following complaints from residents about yellowish and dusty water being supplied to several parts of the city.The discolouration has been attributed to the mixing of silt, clay, and sand washed in from soil erosion following heavy rainfall in Pillur dam’s catchment areas.The turbidity level (measure of the relative clarity or cloudiness of water) reportedly exceeded over 1,000 nephelometric turbidity units (NTU) this year, against the usual range of 10- 50 NTU, recording the highest level in recent years.A senior corporation official said, “Every year, the NTU would rise to 160 during monsoon, and the issue would be resolved in three or four days. But this year, sudden and heavy downpour led to intensified turbidity that has lasted for almost 10-15 days, which is unusual. As of today, raw water recorded 36 NTU, after treatment it reduced to 10 NTU.”The influx of rainwater, silt and soil into the Bhavani River and Pillur reservoir has increased treatment requirements. Officials have stepped up the use of treatment chemicals to maintain water quality. The ferric alum consumption at Pillur II treatment plant has been increased from around one tonne to nearly four tonnes a day, while chlorine dosage has also been increased from 1.5 parts per million (ppm) to 2.5 ppm.Meanwhile, the corporation commissioner said the turbidity levels were very high two weeks ago but reduced over the course of time. “However, some areas of the north zone still report the same problem. Water samples from the dam, the plant and from houses will be collected again for testing.”The commissioner also dismissed claims of an increase in water borne and throat infections. “Until now, we have not been informed of any such health issues, but officials will be instructed to check if there is a surge and take immediate action.”
