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 examin ed: 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 m atrix and its subsequent enrichment in the solid residue following combusti on merits serious attention. This paper examines an overall view of the ars enic level (0.1-23 ppm) in Indian coal and lignites across its geographical range which is significantly less compared to what as encountered in weste rn variety (0.5 - 80 ppm). But this offers little comfort, simply because, steam coal Fed into the thermal power generation units is significantly hig h in ash to generate colossal quantity of fly ash with enriched arsenic to offset that advantage of lower arsenic concentration in Indian coal. Washab ility study reveal that Arsenic is mainly concentrated in inorganic phase i n coal and therefore is vulnerable to mobilization from the ash-dumping zon e to the ground water beneath soil and other nearby water bodies. Fly ash l eachate study also indicate that mobilization of arsenic from the fly ash p ond is favoured at the neutral media close to pH 7. This establishes furthe r that with the onset of monsoon the probability of ash pond being flushed with rainwater may contaminate the adjoining areas more extensively. To obv iate such possibilities, deshaling of coal prior to combustion, and/or simp le chemical treatment protocol of contaminated water as substantiated by re moval kinetics have been suggested.