Arsenic Mitigation Processes on Trial and Tested in Barak Valley, Assam, India.

Abstract

Some of the environmental friendly mitigation processes of iron which was evolved and developed domestically also
applied and tested for the removal of arsenic, which is an extremely toxic contaminant even in very low concentrations.
Based on the combined use of co-precipitation, adsorption, on the principle of aeration (oxidation) of Fe2+ to Fe 3+ and
sedimentation technique for removal of arsenic (As) from drinking water has been evaluated in water from seven wells in
Barak Valley, Southern Assam, India. Field data revealed that As concentrations may, by these methods, be reduced up to
67% to 99% depending on the methods used. The presence of small amounts of ferric salt in water greatly facilitated
sedimentation of the precipitate. Adsorption of inorganic contaminants, which helps precipitation of metal hydroxide solids,
was likely to be the dominant mechanism of As removal. Arsenic in groundwater of some pockets of Barak Valley, Assam,
is present in excess of the safe limit set for India (<50 ?g l-1) while some areas are within the range of the limit set by BIS
(10-50 ?g l-1).The present study is carried out from 2007-2010 on underground drinking water quality at Barak Valley,
Assam, India.