As part of efforts to treat water in contaminated borewells, the
Bangalore Water Supply and Sewerage Board (BWSSB) is planning to install
168 treatment plants in the 110 villages that were newly-added to the
city.

According to T Venkatraju, engineer-in-chief, BWSSB, of the
617 public water borewells located in the 110 villages, 168 were found
to be contaminated.

“Therefore, we are planning to install
treatment plants to ensure that the water, which is supplied, is not
contaminated. As some of these borewells are situated in BBMP areas, we
have already convened a meeting with Palike officials to discuss
modalities of installing treatment plants,” Venkatraju explained.

The
Karnataka High Court had taken suo motu cognizance of deteriorating
groundwater levels in the city and had directed the Karnataka State
Pollution Control Board (KSPCB) to check water quality in public
borewells.

The KSPCB tested water from borewells on 22 parameters,
including pH level, amount of dissolved solids, nitrates, fluorides,
turbidity, sulphates, chlorides, phenol, total hardness, calcium cyanide
ammonia, copper, zinc, iron, cadmium, manganese, lead, chromium and
nickel. Water in 168 borewells, located in 64 villages, was found to be
contaminated and non-potable.

Forty-eight of these borewells
needed chloride treatment plants while 39 needed reverse osmosis plants
to remove nitrates and other contaminants.

As many as 72 borewells needed de-fluoridation plants and disinfection units before they were declared as being potable.

Earlier, official sources had estimated the number of contaminated borewells to be 150.