The amount of water available in the planet is limited. Out of the total available water, 97.5 per is salt water in the Oceans. 1.5 per of the fresh water is permanently locked in the snow clad mountains and glaciers. Only 1 per of the fresh water is available for the mankind for consumption and every use. With the increase in world population, the demand and use of water increases rapidly. At present, 700 million people in 43 countries suffer from water scarcify and in next 15 years, more than 3 billion people will be facing this problem. This means that half of the total world population will not get enough water by 2025.Pollution, from industry and sewage adds another fierce pressure. About two million tons of wastes are dumped every day into rivers, lakes and streams, with one liter of wastewater sufficient to pollute about eight liters of fresh water.
The present day report estimates that across the world there are about 12,000 cubic kilometers of waste water, which is more than the total amount contained in the world's 10 largest river basins at any given moment. Therefore, it suggests, if pollution keeps pace with population growth, the world will in effect lose 18,000 cubic kilometers by 2050 almost nine times the amount all countries currently use for irrigation. With increasing water pollution, the amount of useable water declines. Proper treatment of waste water is very important to safeguard our future generations.