How is water purified?
Water is the basic necessity of life and is used in varied forms in our houses. The water that comes to our homes undergoes a systematic process of purification which involves some of the separation methods we discussed in the previous segments.
Let us look at how the purification system is set up.
The water enters from the reservoir into a tank known as the Sedimentation tank. In this tank, the heavier particles mixed in the water are allowed to settle to the bottom of the tank.
Once this process is done, the water which is above is relatively cleaner. This clean water is allowed to flow into the Loading tank. In a loading tank, coagulants like lime and alum are added to the water. This causes the suspended particles to clump together. and settle at the bottom of the tank.
To remove any other remaining undissolved impurities, the water is passed through a Filtration tank. The filtration tank has three distinct layers, made of fine sand, gravel, and coarse gravel. These layers, made up of different sizes of solid particles, acts as a filter for the water. Only the molecules of water are allowed to pass through and all other impurities are left behind.
With all the visible and undissolved impurities removed, the only impurities left are the unseen bacteria. To get rid of them, the water needs some chemical treatment. The process of Chlorination does this. Chemicals including chlorine are added to the water in the last tank to kill the harmful bacteria.
This is the final step in the water purification process, and we are ensured of clean and relatively pure water.