A Case Study of Chandrapura Thermal Power Station – Leaching Study of Trace Elements from Fly Ashes

Abstract

Electricity generation has been increasing at a rapid pace due to Industrialization and changing life styles. Coal is the major source of energy, since India has vast reserves of thermal power grade coal. Nearly every naturally occurring element is likely to be present in coal and these get entrained in the resultant bottom ash. Indian coals contain high ash coupled with low calorific value, and consequently resulting huge amount of fly ash. This ash accumulates in onsite piles and ponds, thereby resulting in serious environment problems, particularly trace elements contamination of ground and surface waters. This study envisages the environmental assessment of fly ash from Chandrapura Thermal Power Station. Leaching study of fly ash is made by the analysis of leaches from open percolation leaching column experiments over a period of 274 d. Trace elements were observed within the regulatory limits. Many of the trace elements evaluated viz. Cr, Ni, Co, Se, Al, As, B, Ba, Sb and Hg were observed at below detection limits. Na, K, Ca, Mg, Fe, Pb, Cd and other dissolved ions leached at significant concentration levels, while Cu and Zn leached normally at lower concentration levels. The study suggests low-cost high volume utilization of fly ash as fill material for reclaiming surrounding abandoned mined out areas which are environmentally acceptable.