An apprisal of arsenic in Indian coal, propensity of arsenic pollution from coal fired power plants and suggested remedies

A potential source of arsenic mobilization in water was chosen to be examined: and it is none other than solid residue of coal generated from thermal power generating installations. Sheer magnitude of coal being put into use fbr meeting growing energy demand and the presence of arsenic in the coal matrix and its subsequent enrichment in the solid residue following combustion merits serious attention. This paper examines an overall view of the arsenic level (0.1-23 ppm) in Indian coal and lignites across its geographical range which is significantly less compared to what as encountered in western variety (0.5 - 80 ppm). But this offers little comfort, simply because, steam coal Fed into the thermal power generation units is significantly high in ash to generate colossal quantity of fly ash with enriched arsenic to offset that advantage of lower arsenic concentration in Indian coal. Washability study reveal that Arsenic is mainly concentrated in inorganic phase in coal and therefore is vulnerable to mobilization from the ash-dumping zone to the ground water beneath soil and other nearby water bodies. Fly ash leachate study also indicate that mobilization of arsenic from the fly ash pond is favoured at the neutral media close to pH 7. This establishes further that with the onset of monsoon the probability of ash pond being flushed with rainwater may contaminate the adjoining areas more extensively. To obviate such possibilities, deshaling of coal prior to combustion, and/or simple chemical treatment protocol of contaminated water as substantiated by removal kinetics have been suggested.