Mitigation and Remedy of Groundwater Arsenic Menace in India
Mitigation and Remedy of Groundwater Arsenic Menace in India
Mitigation and Remedy of Groundwater Arsenic Menace in India
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<strong>Mitigation</strong> <strong>and</strong> <strong>Remedy</strong> <strong>of</strong> <strong>Groundwater</strong> <strong>Arsenic</strong> <strong>Menace</strong> <strong>in</strong> <strong>India</strong> : A Vision DocumentIt is also to be understood that the arsenic contam<strong>in</strong>ation <strong>of</strong> groundwater <strong>in</strong> the BDP isthe result <strong>of</strong> <strong>in</strong>teraction <strong>of</strong> the aquifer lithology <strong>and</strong> aquifer waters <strong>in</strong> flux <strong>in</strong> a complexevolutionary sequence <strong>in</strong> the mid-Holocene to the present times. Study<strong>in</strong>g the morphologic <strong>and</strong>lithologic makeup <strong>of</strong> the area, its water drawal level pattern, aquifer water chemistry, m<strong>in</strong>eralphases, <strong>and</strong> arsenic-<strong>and</strong>-iron concentration variation pattern, have provided basic <strong>in</strong>sights <strong>in</strong>tothe problem.Towards the mechanism <strong>of</strong> mobilization <strong>of</strong> As, the oxidation model is consideredrelevant only locally, while the reductive dissolution model <strong>of</strong> As from soils is largelyacknowledged as the dom<strong>in</strong>ant processes <strong>of</strong> As mobilization <strong>in</strong> the Gangetic pla<strong>in</strong>s.Removal <strong>of</strong> As from arsenic-contam<strong>in</strong>ated water by suitable filtration techniques, toensure supply <strong>of</strong> arsenic-free water, appears to be a viable practical solution for potable water ifthe related problems, such as sludge disposal <strong>and</strong> operation & ma<strong>in</strong>tenance, are resolvedeffectively. But the agricultural requirement is much more than potable water. Supply <strong>of</strong> treatedgroundwater to meet agricultural requirement by ex-situ arsenic removal technologies would notbe a susta<strong>in</strong>able option or approach.A variety <strong>of</strong> arsenic removal devices have been developed, based on different work<strong>in</strong>gpr<strong>in</strong>ciples, <strong>and</strong> have been extended to fields. Many <strong>of</strong> those could not produce satisfactoryperformance or failed due to lacks <strong>in</strong> O & M or due to sludge disposal problems. Among thevarious removal technologies, lime s<strong>of</strong>ten<strong>in</strong>g <strong>and</strong> iron co-precipitation have been reported to bethe most effective removal technologies, <strong>and</strong> observed runn<strong>in</strong>g satisfactorily, where operation<strong>and</strong> ma<strong>in</strong>tenance problems were taken care <strong>of</strong> by public-private partnership. Majority <strong>of</strong> theoperation <strong>and</strong> ma<strong>in</strong>tenance is l<strong>in</strong>ked to tube wells <strong>and</strong> day-today care, which has noth<strong>in</strong>g to dowith the ARP or its chemical media. Without adequate <strong>in</strong> built ma<strong>in</strong>tenance arrangementsapparently the performance <strong>of</strong> all the devices would suffer. Proper tra<strong>in</strong><strong>in</strong>g <strong>and</strong> mobilization <strong>of</strong>the user community <strong>in</strong> the operation <strong>and</strong> ma<strong>in</strong>tenance aspect would be an essential task beforeany future <strong>in</strong>stallation <strong>of</strong> ARP programme can be envisaged. Thus, future emphasis should beoriented around <strong>in</strong>-situ remediation at the source-aquifer level <strong>and</strong> also chemical fixation <strong>of</strong> thecontam<strong>in</strong>ant at the source should be properly explored through proper calibrated <strong>and</strong> configuredstudies <strong>and</strong> experimentations.NIH & CGWB 123
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