This comprises off sand and anthracite as filtering media and polishing media respectively. Internally it is fitted with inlet distributor and a bottom collecting system. Externally, it is fitted with frontal pipe work and isolation valves. Sand is used for removing the suspended particles and anthracite removes the odor and colour etc to make the water fit for various application. Pebbles and gravels are provided to support to both the media. This filter is to be backwashed after accumulation of suspended solids, however, before carrying out the backwash, air scouring is also to be done for loosening of dirt and suspended solids. Limit for the backwash in these filers is governed by differential pressure across the filter.