B.R. Jayasekara and U.A.D.P. Gunawardena
Department of Forestry and Environmental Science, University of Sri Jayewardenepura , Sri Lanka
A new type of a solid waste which is known as fly ash will be available in Sri Lanka at the end of year 2010 due to operations of the Coal power plant, Norochcholai. Fly ash is a superfine, powdery byproduct which is carried away from the power plant boiler in the flue gas during coal combustion. It is expected to generate 70,000 tons of fly ash annually from the coal power plant. The objective of the study was to investigate the potential for effective utilization of fly ash originated from the Coal power plant while minimizing the environmental and social impacts.
The methodology of the study involved three surveys; an expert opinion survey to identify environmental impacts of fly ash and potential utilization opportunities of fly ash; an industrial survey to investigate willingness of industries to utilize fly ash and a contingent valuation survey to estimate the potential damage cost to the surrounding communities. In order to find out the best uses of fly ash financial and economic analysis were carried out for each and every industry that have the potential to use fly ash.
The expert opinion survey indicated that only the fine portion of fly ash (20%) is usable for cement production and the rest could be used for industries such as ready mix concrete, asbestos cement sheets, dam and road construction and cement based products such as light weight concrete blocks, clay-fly ash bricks, etc. The main impacts of land filling of fly ash include contamination of soils and water especially due to highly alkaline leachate.
The financial analysis of fly ash utilization indicates that asbestos cement industry receives highest financial benefit while the lowest were received by cement industries. However the highest economic benefit of fly ash utilization is gained by cement production which is Rs 13,330.35 per ton. Total cost of land filling of fly ash (per ton) is estimated as Rs 228,721.72 and therefore the full utilization of fly ash is very important while avoiding land filling.
In conclusion, the best practice to handle fly ash originating from the coal power plant is to utilize the ash in order gain the highest economic benefits to the country. This is very important because the fly ash storage capacities in the power plant are only enough for two days.