Metal Leaching Potential in Coal Fly Ash

Thermal power plants are the major source of electricity generation in India and most of them use pulverized coal as the fuel producing enormous quantities of coal fly ash every year. The method of disposal adopted is by wet sluicing in on-site fly ash ponds. This disposal in the form of dilute slurry has a high potential for leaching into the surrounding soil and groundwater. The coal fly ash contains trace metals like As, Cr, Zn, Cd, etc which are toxic in nature and thus, the wet disposal of coal fly ash has serious environmental concerns. This paper assesses the leaching potential of coal fly ash from six thermal power plants in Maharashtra, India. The maximum leachable quantities of some trace metals present in coal fly ash are computed by a Sequential Extraction Procedure (SEP) and results are compared with values obtained by Toxicity Characteristics Leaching Procedure(TCLP).