Problem of arsenic in groundwater - a feasible solution

West Bengal in India and Bangladesh achieved remarkable successes in providing drinking water at low cost to the rural population through sinking of shallow tubewells in floodplain aquifers. Unfortunately arsenic contamination of shallow tubewell water in excess of the acceptable limit has become a major public health problem in both the countries. The contamination scenario in West Bengal and Bangladesh appears to be the worst detected so far worldwide, both in terms of area and population. The probable source of arsenic has been reported to be through geological formation. Thousands of people have already shown the symptoms of arsenic poisoning and several millions are at risk of arsenic contamination from drinking tubewell water. Arsenic toxicity has no known effective medicine for treatment, but drinking of arsenic–free water can help the arsenic–affected people to get rid of the symptoms of arsenic toxicity. Hence, provision of arsenic–free water is urgently needed to mitigate arsenic toxicity and protection of health and well–being of rural people living in acute arsenic problem areas of Bangladesh and India. The most commonly used technologies include oxidation, co–precipitation and adsorption onto coagulated flocs, adsorption onto sorptive media, ion exchange resin, and membrane techniques. In this chapter the above methods have been discussed along with a very low–cost adsorbent called CalSiCO developed in our laboratory at the Indian Institute of Technology, Kharagpur.