Effluents are liquid waste flowing out of a factory or a power plant.

Minute quantities of alum are added to facilitate sedimentation.

Surface water is not obtained from the seas.

Boiling water for 15 - 20 minutes kills the harmful germs in it.

Layers of sand, gravel and charcoal are present in the filtration chamber.

Potable water should not be full of micro-organisms. It should be free of micro-organisms.

Water that is suitable for drinking is called potable water.

Filtration can also be done via ceramic candles.

Ozone is a replacement of chlorine as a disinfectant as chlorine has a bad odour while ozone does not.

Purifiers used in home these days have three stages of purification viz, filtration, adsorption, disinfection.

Chemical treatment of water involves treatment of water with potassium permanganate.

Ultraviolet lamp is used for purification of water.

Bleaching powder is used in chemical treatment.

Out of the total water found on Earth, 0.01% of water is available for consumption.

There are three steps involved in the purification of water in treatment plants. They are sedimentation, filtration and chlorination.