ENVIRONMENTAL FRIENDLINESS OF DIFFERENT DETERGENTS

Abstract

Detergents are widely used in both for household as well as industrial purposes. Hundreds of thousands of tonnes detergent used annually with a retail value of billions of rupees. The production, use, and disposal of such wide variety of chemical is to have an impact on environment. Detergent builder (STPP) is added to enhance the sufactant performance. But once the washing is done, the phasphate get washed along with the dirty water into the water bodies. An effort was made in the present investigation to characterise the solutions prepared by dissolving in water 55 detergents available in North Indian market in the form of cakes, powders and liquids. Based on the analytical results their likely effects on is environment were discussed. Sodium tripolyphosphate (STPP) whichAused as a builder was found to range from 1.8% to 31.9%, a variation of above 15 fold. Higher concentration of STPP in detergent is associated with eutrophication of natural water bodies. In general, most widely used and high prise range detergents were found to contain higher amount of STPP (>25%). Almost all the detergents analyzed had STPP > prescribed limit of 2.2% by weight. Liquid detergents were found to have higher COD (ave.136.1g/kg) than cakes (ave.30.5g/kg ) and powders (ave. 25.3 g/kg). Ten percent solution of only a few detergents were found to have pH > prescribed limit of 11. In general, liquid detergents were found to have -least impact on the natural pH of water. Alkalinity of 1% solution of different detergents was found to vary from 365 to 5470 mg/L as CaCO3. iii Detergents add high amount of filterable and non-filterable solids to water. Filterable solids ranged from 80-576 g/kg while non-filterable solids varied from 37.8-825 g/kg. Addition of detergents significantly alter the cationic and anionic balance of natural waters. Detergent containing water was observed to have colour and turbidity. Turbidity of 1% solution of different detergents ranged from 20-1760 NTU. At present, there are no rigid guidelines in India about the percentage of various constituents in a detergent formulation from the point of view of environment. Constituents in detergents available in North Indian market vary widely and are likely to have widely varying impacts.