Water is essential for the sustenance and well-being of all lifeplant, animal, and human. The total body water (TBW) content averages 60% of body weight in men and about 55% in women. Vegetables contain about 80% to 90% water. Rivers and lakes form the source of surface water, while wells form the source of ground water. Water from these sources does not usually conform to quality standards for human uses like bathing, drinking, washing machines, dishwashers, boilers and water heaters, pets, and sometimes even for plants. It is rendered unfit for use due to acidity, smell, color, heavy metals, dissolved solids (TDS), pollutants (organic compounds like insecticides and herbicides), and bacteria and microbes. Hence, the water needs to be treated to obtain the desired quality, free from contaminants, for human consumption. Treatment of water depends on the contaminants present in it. Any of the following methodsor preferably a judicious combination of the methodswould readily offer water of desired quality. Common methods used for treating water are water softeners, water treatment chemicals, distillation, activated carbon filters, ultraviolet (UV) filters, and reverse osmosis. Water softeners remove the calcium and magnesium salts by replacing them with sodium salt. The water thus obtained is not hard. Water treatment chemicals like soda ash neutralize the acidity of the liquid. Distillation vaporizes the water, which is then condensed to give pure water. This does not remove volatile organic impurities that will co-distill along with water. Activated carbon filters work by the principle of surface adsorption; they remove organic impurities. Ultraviolet filters are used to kill the bacteria by ultraviolet radiation. Reverse osmosis removes about 90% of all the impurities present using a semi-permeable membrane. Thus, it is important to properly test the water and use suitable measures for its treatment in order to meet the quality norms. |
