Toxicologie environnementale et analytique

A Study on Leaching Property of Hazardous Substances in Coal Ash Through the Column Test (Percolation test)

Abstract

Jeon TW, Park JE, Hwang DG, Jeong MJ, Um NI, Kang YY, Shin SK, Hong SY, Lee HS and Jang MJ

The aim of this study is to identify the characteristics of hazardous substances of coal ash and to evaluate the environmental contamination possibility in order to enable the recycling of coal ash generated in thermal power plants. Currently, the various requirements for the activation coal ash (bottom ash) thermal power plant recycling of emitters and are also required by law to be considered as the country’s environmental impact on the environment of large amounts of recycling coal ash. In South Korea’s national assembly in requesting an environmental impact if the potential for soil and groundwater that can occur when you recycle roadbed, cover soil of coal ash were performed in this study. Based on this study we intend to develop a plan to expand the use of recycled coal ash. There are 10 coal-fired thermal power plants in Korea. About 8.6 million tons of coal ash was generated from those power plants in 2012. Coal ash is composed of fly ash (82%) and bottom ash (18%). While most of the fly ash is recycled as ready-mix concrete admixtures and cement additives, bottom ash is left unused in landfill located within power plant. So, in this study we assessed the recyclability of the bottom ash generated by Samcheonpo and Hadong thermal power plant. The concentrations of hazardous substances contained in coal ash (bottom ash) were generally lower than criteria for contaminants in soil and standard for hazardous substances contained in designated waste. Result of column leaching test for potential environmental impact assessment indicated that increased leaching led to reduced ionic strength of coal ash. Heavy metals did not show any clear pattern of decreased concentration; however the level of heavy metals in coal ash was generally low. Ecological toxicity in the effluent from column was the level of wastewater disposal criteria (2TU) of Korea, which is judged to be not concerned level in environmental aspects.