Kolkata Municipal Corporation uses more chlorine to treat water as Hooghly turbidity rises
Times of India | 21 September 2024
KOLKATA: The KMC water supply department is charging more chlorine into the raw water before its filtration at its Palta water treatment plant.
This is to disinfect the raw water and make it safe for drinking as turbidity level in the Hooghly nearly doubled in two days, from 400 nephelometric turbidity unit (NTU) on Wednesday to around 700 NTU on Friday due to release of storm water from DVC-run barrages in high volume.NTU is the presence of suspended particles in water.
"When the level crosses 500, it becomes a challenge for us to keep the supply of water normal. Now that the turbidity level is about to cross 700 NTU, we have reasons to be worried," said a KMC water supply department official.
Engineers fear the high level of turbidity may damage machines used in the sedimentation tank zone.
A KMC engineer said that if the turbidity level rises further and any machine goes out of order, it would be difficult for the civic body to supply safe drinking water to vast parts of the city.
"Several machines work together in our century-old plant to make the filtration process a success. Now we are extremely cautious about the protection of these machines," said a civic official.
Similarly, the engineers at Garden Reach and Dhapa plants are also battling high levels of turbidity. While Garden Reach supplies potable water to large parts of south Kolkata, including the added areas such as Garden Reach, Behala, Tollygunge (parts) and Jadavpur, the Dhapa plant caters to drinking water needs of residents staying along EM Bypass.
According to a KMC official, the slow sand filtration bed at the Palta plant has proved to be a saviour in this hour of crisis.
"It is due to this slow sand bed that we have been able to keep our plant operational. This bed is absorbing the high volume of sludge and keeping our plant operational," he said. Besides, the plant engineers are using an adequate volume of alum as a coagulant to make the water safe for drinking.