STUDY ON THE CONCENTRATIONS AND PARTITIONING OF HEAVY METAL AMONG FLY ASH AND BOTTOM ASH FROM MUNICIPAL WASTE INCINERATION

• Main Authors: Feng-Yi Tseng, 曾豐益
• Other Authors: Moo-Been Chang
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/64262060919032977511

碩士 === 國立中央大學 === 環境工程研究所 === 82 === Due to its dense population, limited land for waste disposal, and increases in per capita waste generation, Taiwan is entering a phase of applying incineration technology as an alternative to landfills for municipal solid waste (MSW) management. However, the potential emission of toxic heavy metals from MSW incinerators into the environment may pose serious threats on human health and ecology. This issue has not been properly addressed and has caused more public concerns in Taiwan recently since the concept of separation and recycling of refuse is not generally adopted and the incinerators for hazardous wastes are not commonly available here. In this study, the concentrations of some heavy metals (including Hg, Cd, Pb, and Zn) which exist in fly ash and bottom ash coming out of a typical MSW incinerator located in northern Taiwan were determined. Furthermore, the physical properties, such as particle size, surface area, and porosity of fly ash were also characterized for better understanding of their potential effects on the concentration of these heavy metals. Preliminary results indicate that the concentrations of mercury, cadmium, and zinc are generally higher in fly ash than that found in bottom ash. In fact, the property of municipal solid wastes, varying operating conditions within incinerators, combustion efficiency, and chloride content in the flue gas streams all affect the partitioning of heavy metals among flue gas, fly ash and bottom ash. As a result, the concentration of heavy metals contained in fly ash may vary with different particle size. In this study, collected fly ash was segregated into seven different fractions based on particle size (Mesh 50-Mesh 325). Analysis of particles with each fraction indicates that particles around Mesh 50/80 with a specific area of about 6 m2/ g tend to adsorb more heavy metals (including Hg, Cd, Pb, and Zn) than the particles with other sizes.