Rise in Hooghly River turbidity forces KMC to increase chlorine use at Palta

Kolkata: With turbidity in Hooghly River water increasing due to water release from DVC-run barrages, Kolkata Municipal Corporation (KMC), has taken the decision to charge more chlorine into the raw water before its filtration at Palta water treatment plant.

It was reportedly learnt that such a move was contemplated to disinfect the raw water to make it safe for drinking.

According to KMC, the presence of suspended particles in water increased on Friday following the release of stormwater by DVC-run barrages. The adding of chlorine is part of a precautionary measure. It is being done at water treatment plants at Dhapa, Garden Reach and Palta.

Further, the civic body fears that abnormal levels of turbidity may damage machines used in sedimentation tank zone.

In case the machine goes out of order, it would become difficult to supply safe drinking water to a large part of the city, it was learnt. Garden Reach supplies potable water to large parts of south Kolkata while Dhapa plant cater4s to drinking needs in areas along EM Bypass.

The civic body feels that if DVC continues to release high volumes of water the Palta plant might get adversely affected and hence steps are being taken against the deposition of mounds of sludge.

However, the issue of turbidity of Hooghly water has been longstanding.

In 2023, the Palta plant was put on high alert due to sudden spurt in turbidity level in the river. This had led the civic body to raise the quantity of alum in raw water and also increase the quantity of residual chlorine.

According to KMC, 100 nephelometric turbidity units is normal but beyond that it becomes a matter of concern.