1.7.2 Remediation
Various techniques might be adopted to lessen the concentration of Se in drinking water. The commonly applied techniques are ion exchange, activated alumina (AA), reverse osmosis (RO), and distillation. Ion (anion) exchange can decrease selenium by 90–95%, as selenate ion is highly favoured. Though oxidation of Se (IV) is more problematic, it can be done easily with the help of free chlorine. Se (IV) can be transformed to Se (VI) within five minutes by maintaining the concentration of free chlorine to 2 mg/L. The pH between 6.5 and 8 is observed to be an ideal rate of oxidation. Removal rates for other methods used for selenium elimination are distillation (>98% removal), activated alumina (85–95% removal), and reverse osmosis (RO) (>90% removal) (CGWB 2014).
1.8 Conclusion
India has different biogeographical regions including the Himalayan regions, desert, semiarid areas, Western Ghats, Deccan Plateau, Gangetic plain, northeast India, islands and coastal regions. Based on this study, it can be seen that most of the geographical areas of India are facing geogenic contamination in groundwater. Arsenic and fluoride contamination have been reported in bulk in the Gangetic Plain. Salinity problems are more concentrated in the coastal, arid, and semiarid regions, while heavy metal contamination has been observed more or less everywhere in India. There is a need for continuous monitoring of the groundwater parameters to check the concentration of the geogenic contaminant in the water system. The remediation method should be applied in the regions of the geogenic contaminants to cope with the present and future worst situations of health‐related problems.
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