2 Methods Used in the Purification of Water on Large Scale
Water is purified on large scale for supply to a city or a town. It is also purified on small scale for domestic use. image source: groksurf.files.wordpress.comIn the purification of water on large scale following methods are used: ADVERTISEMENTS: l. Slow sand filtration (biological filtration).2. Rapid sand filtration (mechanical filtration). 1. Slow Sand Filtration: This system was first introduced in England about more than a century ago and still commonly used. Hence it is also known as English system. In slow sand filtration following stages are involved:(a) Storage ADVERTISEMENTS: (b) Filtration(c) Chlorination(a) Storage:The raw water from the source, usually a river, canal or a stream is collected in natural or artificial large open reservoirs known as settling tanks. The water is allowed to remain there for 1 to 2 days.…