Solid Waste and Ecological Issues of Coal to Energy

Abstract

This paper provides an overview of environmental issues in the coal-to-energy industry. Coal to energy will be the major energy source for foreseeable future. The waste generated from the coal-to-energy process and the ecological degradation during the mining and processing of coal are two main issues affecting coal as a future main energy source. Hence, this paper provides an overview of the solid waste and ecological issues during the coal-to-energy process and proposes ways to fully utilize coal fly ash and to mitigate the ecological issues. Fly ash, a major component of combustion waste of coal to energy, is an industrial by-product that is recognized as an environmental pol- lutant. Although it is treated as a waste, the mineral chemistry of fly ash is of economic value. The main reasons for the low utilization rate of coal fly ash and theways of achieving full utilization are discussed first. The issues involved in the storage of vast quantities of coal fly ash are also summarized. Based on the analysis, full utilization of coal fly ash is feasible in the United States by the processes of grinding fly ash and 40% cement replacement. However, such actions would require the development of a fly ash classification system accounting for pozzolanic activity and cementitious properties, alkali-aggregate reactivity, and sulfate resistance. Also discussed are the ecological issues and existing problems during coal mining including water pollution, coal mining waste, and land subsidence. Several proposed effective solutions were reviewed, and it was determined that the ecological degradation during mining could be minimized. DOI: 10.1061/(ASCE)HZ.1944-8376 .0000071. © 2011 American Society of Civil Engineers.