(398d) Redistribution of Heavy Metals in Incineration Bottom Ash Through Particle Size Reduction

Incineration is the main treatment process for municipal solid waste in Singapore. The incineration bottom ash (IBA) is used primarily for landfills. Therefore, it is important to study the physical and chemical properties as well as the leaching characteristics of heavy metals in IBA. In this study, both of physical (including size distribution, density and circularity) and chemical (composition and typical heavy metal contents) properties of incineration bottom ash (IBA) are analyzed. Fractional distribution is also used to determine the leaching properties of the heavy metal contents. XRF results indicated that Si, Ca, Al, Fe are the main elements of the bottom ash in Singapore. ICP-AES showed that the ash contained more than 5000 mg/kg of heavy metals. It is found that 17.8% of the heavy metals are leachable while carbonate bound is the main leaching mechanism. The effect of particle size reduction process on the re-distribution of heavy metals is also explored.