Raw water is first treated to remove the suspended colloidal matter. Small suspended particles in the raw water are coagulated by using poly-electrolyte and coagulant at higher pH. This is then passed through a tube settler where coagulated suspended matter settles down and clearer water flows up. Coagulated suspended matter is taken out from the hopper bottom of tube settler in the form of a thick sludge.
Clear water is further treated in the second stage. A dual media filter is provided for further reduction of suspended matter to a level of less than 5 ppm. This filter works in pressurised conditions. A clear water pump is provided at the inlet of the filter to feed clarified water.