What is Water Purification Methods?

Sometimes water contains some unwanted substances which is not suitable for drinking. This type of water needs purification. The aim of purification is to make water fit for specific purposes. Various methods used for the purification of water are as follows.
Distillation method: The dirty water is boiled to produce steam. This steam is cooled so that it condensates to form water droplets. The droplets are collected in a container. The collected water is pure mineral free water. The residual water contains impurity and contaminants so it is discarded. Now a days solar energy is also used for distillation of water. These solar stills can be used in the remote areas where there is scarcity of electricity. However 99.9% pure water can be obtained by distillation.
Reverse Osmosis (RO) method: In this method water is forced through semi-permeable membrane. The water obtained is free from unwanted substances and clear. This process can also be used to desalinate seawater. No chemical is used in this process. The membrane used is to be disposed of after its specified life period. RO filter is now a day used in most of the households.
Boiling: It is the oldest method of purification of water. It is recommended to boil water (at 100°C) for 10 minutes to eliminate most of the microbes responsible for intestine related diseases.
Water disinfection with chlorine (Water Chlorination): Chlorination is the process of adding chlorine or its compounds to water. Chlorine is highly toxic that kills certain bacteria and other microbes. This method is used to prevent the spread of waterborne diseases like typhoid, cholera etc.
Ultraviolet (UV) disinfection: Ultraviolet light is used to disinfect bacteria from the water. Ultra violet system destroys almost 99% of harmful micro-organisms. This method does not use any chemical, and is simple and effective.