Describe different methods of purifying water in the city.
Water supplied to our homes contains several impurities such as sand, salt and clay. Therefore, it is essential to purify water to be made suitable for consumption. The three main process involving purification of water in cities are:
Sedimentation: In this process, water from the rivers is collected in large tanks so that the suspended impurities settle down and later removed.
Filtration: In this process, all the other insoluble impurities are removed by passing the water through filter beds.
Chlorination: In this process, chlorine it added to the water to kill the microorganisms present if any. This water is further filtered and stored and finally supplied to homes via water mains.
Distillation: In distillation, water is first heated to convert into vapours. As vapours rise, they leave behind the impurities, and then they are condensed into a separate container by passing through a condenser.