Leaching Characteristics of Fluoride from Coal Ash
More than 100 million tonnes of coal fly ash is produced annually in India from combustion of coal in power plants. It is expected that up to 2020 AD about 150 million tonnes of coal ash will be produced due to burning of coal in power plants. This will require about 30,000 hectare of land for ash disposal. One of the main problems in disposing of big quantities of coal ash is the possible leaching of different pollutants, including fluoride. A thorough investigation regarding leaching of fluoride from fly ashes is much essential to know the impact of fluoride due to its leaching from fly ash to ground water as well as surface water. In the present paper, short term and long term leaching studies have been carried out on fly ash, bottom ash, pond ash and weathered ash of Chandrapura thermal power station (CTPS), Jharkhand and Ramagundam thermal power station (RTPS), Andhra Pradesh. The amount of fluoride released in different experiments has been evaluated. A field investigation at Damoda abandoned open cast mine of Bharat Coking Coal Limited, filled with pond ash of CTPS has been done. Concentration of fluoride in ground water beneath the ash filled mine has been evaluated on monthly basis. Environmental impact of fluoride and remedial measures for ash disposal has been discussed.
Cox, J.A., Lundquist, G.L., Przyjazny, A. and C.D. Schmulbach (1978). Leaching of boron from coal ash. Environmental Science and Technology, 12: 722-723.
Fleming, L.N., Abinteh, H.N. and H.I. Inyang (1996). Leachant pH effects on the leachability of metals from fly ash. Journal of Soil Contamination, 5(1): 53-59.
Gregory, R.M. and F. Roy (1985). Trace elements concentration as a function of particle size in fly ash from a pulverized coal utility boiler. Envi. Science Technology, 19(9): 796-803.
Liem, H., Sandstrom, M., Wallin, T., Carne, A., Rydevik, U., Thurenius, B. and P. Moberg (1983). Studies on the Leaching and Weathering Processes of Coal ashes. Water Science Technology, 15: 163-191.
Piekos, R. and S. Paslawska (1998). Leaching Characteristics of Fluoride from Coal Ash, Fluoride, 31(4): 188-192.
Prasad, B., Benerjee, N.N. and B.B. Dhar (1996). Environmental Assessment of Coal Ash Disposal: A review. Journal of Scientific & Industrial Research, 55: 772-780.
Prasad, B. and K.C. Jaiprakas (2000). Studies of Selected Coal Fly Ash leachates for Environmentally Safe Disposal. Indian J. Environ. Prot., 20(4): 275-279.
Prasad, B., Mondal, K.K. and A. Gupta (2004). Impact on water Environment due to Leaching of Heavy metals from Indian fly ash. Proceedings of International Seminar on Mineral Processing Technology 2004, Bhubaneswar, pp. 793-801.
Querol, X., Umana, J.C., Alastuey, A., Ayora, C., Lopez-Soler, A. and F. Plana (2001). Extraction of soluble major and trace elements from fly ash in open and closed leaching systems. Fuel, 80: 801-813.
Theis, T.L. and K.H. Gardner (1990). Environmental Assessment of Ash Disposal. Critical Reviews in Environmental Control, 20(1): 21-42.
Vander Hoek, E.E., Van Elteren, J.T. and R.N.J. Comans (1996). Determination of As, Sb and Se Speciation in fly ash leachates. International Journal of Environmental Analytical Chemistry, 63: 67-79.
Wadge, A. and M. Hutton (1987). The Leachability and Chemical Speciation of Selected Trace elements in fly ash from Coal combustion and Refuse Incineration. Environmental Pollution, 48: 85-99.
Wasay, S.A. (1992). Leaching behavior of trace toxic metals from fly ash, their seepage control to ground water and utilization of fly ash. Journal of Environmental Science and Health, A27(1): 25-39.