PREMISE •Water is a vital body ﬂuid which is essential for regulating the body processes such as digestion, transport of nutrients and excretion. Life on planet earth exists because 71% of its surface is covered with water. However, water is also required for many household and industrial processes. This water, once used, gets polluted with many harmful chemicals and salts and cannot be used for the purpose of drinking. Apart from that, many non-degradable and harmful materials such as plastic are also dumped in water bodies. These chemicals ultimately seep into the ground to pollute the underground freshwater too. •Apart from industrial waste, another factor which is causing the scarcity of water is global warming. With the increasing development of industrialization, number of vegetation is decreasing, which is causing the formation of green-house gases. With each passing year, the atmospheric temperature of earth is increasing. After 100O centigrade, water transforms into gaseous state and starts evaporating. Therefore, less availability of drinking water. •At present, only 3% of earth’s water is fresh, non-saline water and only 1% water is drinkable. With the present rate of increasing population and industrialization, all fresh water will be consumed very soon. And life on earth will not survive one day without drinking water. •To sustain the water on earth, we need to recycle the waste water and free it from harmful chemicals. This can be done with the help of a wastewater treatment plant.