It is often said that water is cure for all diseases. But there is an irony as well. Water is also the reason for several diseases. Contaminated water carries with it several germs, which when enter our body, makes us fall sick. Algae, Bacteria, viruses, Giardia, Cryptosporidium, Campylobacter and parasite present in water make us fall sick.
Even lead and copper are present in water. That is why, it is always advised that we should drink germ-free and safe water. Water should be treated properly and made suitable for drinking. The water treatment plant where water is purified should be of the most optimum level.
The treatment of water is a lengthy process and has several steps. Have a look at the three main stages of Water treatment process:
The primary stage removes the larger solids from the water. At first the water is pumped and stored in one place. The water is then screened and stored. It is in the primary stage that water is conditioned and chlorinated beforehand.
The secondary stage process includes usage of variety of techniques to remove finer solid pieces, organic and inorganic material and microorganisms as well. It is in this stage that the pH balance of water is adjusted; the contaminants are flocculated and grouped. After removing the sediment, the water is filtered. Ultra filtration of water is also done. 
In the final and tertiary stage, the water is once again treated. The impurities which are still left are removed by adding disinfectant to the water. Ultra violet radiation, Ozone, Chlorine,Chlorine dioxide are used to purify in this last stage of water treatment process.