Effect of washing on the chlorine content and heavy metals in bottom ash from municipal waste incinerator

• Main Authors: Han-Pin Wu, 吳品漢
• Other Authors: Wen-bin Liao
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/14205821058008474390

碩士 === 國立中興大學 === 環境工程學系所 === 96 === In Taiwan, Municipal Solid Waste (MSW) was primarily disposed of landfills in the past. Due to the limitation of population density and availability of land, the incineration of MSW was widely used since 1993. After incineration, 20-25% by weight of incinerator ashes is produced. It is expected that we will reach at least 80 percent utilization rate of ashes by the end of 2009. How to enhance the utilization of bottom ash in 2009 was the focus of current research. Bottom ash after the pretreatment could be reached the first type of reuse bottom ash product was the key point. The results showed that the high chloride content of bottom ash could not achieve the highest quality standard of the first type (chloride content ≦ 0.024%), which lead to low widespread application of reinforced concrete. In this study, washing bottom ash by different liquid-solid ratio was used to reduce chloride content of bottom ash. The experimental results showed that the method of washing bottom ash by returning three washing times, and then replaced of new water(L/S 1/1) could reduce the chloride content. The chloride content of washing bottom ash was between 0.0280 to 0.0338 percent, and they were still slightly higher than the first type of reuse bottom ash product in standard chloride limits 0.024 percent. Compare with the two leaching methods, return washing and replacing new water were both effective to reduce the chloride content of bottom ash. Also before and after leaching bottom ash, the bond style of heavy metals like as lead, cadmium and copper showed that weak bond style phase was changed to lower amount. Combined of the two leaching methods was not acceptable in operating costs, so how to effectively remove the chloride content of bottom ash is worth developing in the future. Key words：Bottom ash, Chloride, Reused, Leaching