Contamination Analysis of Coal Ash and Treated Marine Clay

Abstract

Abstract The production of coal ash waste is rising alongside the need for power. Therefore, it is necessary to reuse coal ash waste. However, it is unclear if coal ash is genuinely safe for the environment. In this study, coal ash waste and treated marine clay will be subjected to toxicity characteristic leaching to determine the ground contamination caused by coal ash, cement, and marine clay stabilisation. Using the US Department of Environmental (DoE) standard, all three samples of bottom ash, fly ash and treated marine clay (15% 50BA:50FA) showed values below DoE regulatory limits, with the treated sample having the lowest. Using the Malaysian Water Standard, it was determined that the quantities of Cd, Se, and Ag in all three samples were within the regulatory limits established by the Malaysian Water Standard. Except for Cr and Hg, the concentrations of elements identified in the treated 15% 50BA:50FA sample were all within regulatory limits. In descending order, the trend of heavy metal leaching was Ba > Hg > Cr > As > Pb > Ag > Cd > Se, with Ba leaching the most. According to the U.S. Department of Environmental Protection, coal ash and stabilised marine clay are deemed environmentally safe (DoE). For the Malaysian Water Standard, however, water leached from treated marine clays could not be consumed directly. It must be processed before being supplied to consumers.