Arsenic Problem in Groundwater Sources and Treatment Technologies, Indian Experiences

Groundwater arsenic (As) contamination is prevalent in different parts of the world to varying extents; however, its severity in India is a major concern, which has garnered significant global attention. The nature of the problem is considered to be geogenic. The identification of this crisis took place not too long ago; still it has managed to acquire the form of an endemic in the country. Millions of individual are getting vulnerable to arsenicosis on getting exposed to As polluted water. The concentration of the metalloid in the Indian groundwater reserves is often found to be as high as few thousand ppm, which is way beyond10 µg/L (10 ppb), the permissible limit of the metalloid in drinking water, set by WHO. Viable options for mitigating this problem and supply clean water to the affected populace include either identification of alternative As-free aquifers or developing new technologies for the treatment of As contaminated water. The major arsenic treatment units (ATUs) or arsenic removal plants (ARPs), installed in different As affected areas all over the country, are based on several conventional principles namely adsorption, oxidation, precipitation-filtration, coagulation-flocculation, electro-coagulation and membrane separation. Implementation of a single technology or devising an end-of-pipe solution for the remediation of As contamination seem far-fetched due to nature of the aquifers, socio-economic conditions and geo-political issues. The review aims at understanding the current scenario of the problems associated with As contaminated groundwater with respect to the Indian peninsula. It also emphasizes on the different technologies implemented for As removal, in terms of sustainability and economic feasibility.