Potential Risk by Disposal of Bottom Ash from Thermal Power Plants and Minimization by Addition of NaHCO3

Abstract

In the present study, the leachability of traced elements from the bottom ash of three different Indian power plants was investigated. Environmental impact of bottom ash was studied by varying the liquid-to-solid (L/S) ratio from 20:1 to 60:1. Leaching results show the presence of a major proportion of elements Mn, Mg, Cr, Zn and Cu and a minor proportion of Pb, Fe, Co, and Mo. The effect of the addition of sodium bicarbonate (NaHCO 3 ) on leaching characteristics of bottom ash was also studied. Leaching concentration of bottom ash samples reduces with addition of additive from 0.2% to 0.6% and found to be optimum with 0.4% the addition of additive. This aspect of the investigation helps to design the ash disposal system for higher solid concentrations to minimize the environmental pollution.