INTRODUCTION Widespread contamination of drinking water with arsenic has been a serious problem, especially in West Bengal, India, Bangladesh, Chile, Vietnam and China. The presence of arsenic in drinking water is mostly due to natural geological processes such as weathering reactions, biological activity and volcanic emissions, as well as anthropogenic activities 1 . Since arsenic is highly toxic and carcinogenic, the WHO, U.S. EPA and a number of countries has revised the guideline for

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... maximum contaminant level in drinking water from 50 to 10 µg/L. Even, the state of New Jersey of USA proposed that the total arsenic in drinking water should be less than 5 µg/L to ensure the health of people 2 . A number of treatment techniques have been developed for the removal of arsenic from drinking water, namely, coagulation, ion-exchange, adsorption and reverse osmosis. Among various arsenic removal technologies, coagulation and adsorption are believed to be a relative simple, efficiency and cost effective processes [3] [4] [5] . Many coagulation and adsorption technologies have been reported to be capable of removing arsenic to levels lower than 50 µg/L, but with the implementation