STUDIES ON HERBICIDE - 2,4-D REMOVAL FROM WASTE WATER USING ADSORPTION

Abstract

Pesticide industry is one of the highly polluting industries. There are problems of pollution of surface and subsurface water bodies, and organic compounds in water get increased. Besides water, pesticides have also been found to be present in air and soil to the extent of being harmful. Pesticide industry has been included in the top 29 industries requiring Environmental Impact Assessment and environment clearance from Ministry of Environment and Forest. 2, 4 - dichlorophenoxyacetic acid is largely used as a herbicide and growth regulators in fruits. It can cause nausea, vomiting and depression. Liver and kidney injuries have also been reported. It has not been found to be amenable to conventional treatment processes like the activated sludge process. Adsorption is by far the best available technique of treating wastewater having 2,4-D. Activated carbon is the most commonly used adsorbent. However due to high cost and 10-15% loss during regeneration some other low cost adsorbents have been tried. These include primarily bagasse, fly ash, wood, peat, saw dust, etc. Present work has been carried out to assess the suitability of bagasse fly ash for the removal of 2,4-D. Few runs have also been conducted with activated carbon for comparison of adsorption capacity, effect of various parameters like adsorbent dose, pH, time, initial concentration and temperature have been investigated in batch system. Kinetics of removal and adsorption isotherms have also been presented. Removal of 2,4-D -to the extent of 94% and 82% by activated carbon and bagasse fly ash respectively under normal conditions. Reduction in COD and BOD have also been investigated and reported subsequently. The results show that bagasse fly ash can be used in the tertiary stage for removal of 2,4-D. Although higher removal is obtained with activated carbon. However, the low cost of bagasse fly ash in comparison to activated carbon makes the whole process attractive and economically viable..