Feature of slow filter (w.r.t. fast filter) is/are:

Ans. is 'd' i.e. Takes more time for purification o Slow sand filter occupies large area (more space). o Slow and filter requires less skilled operation. o Slow sand filter removes more bacteria and has better bacterial control (99.9-99.99%) o Slow sand filter requires longer duration for purification. o Size of sand is smaller (0.2-0.3 mm).