Li Loretta Y, Ohtsubo Masami, Higashi Takahiro, Yamaoka Shinya, Morishita Tomotaka
Department of Civil Engineering, The University of British Columbia, 2324 Main Hall, 2010-6250 Applied Science Lane, Vancouver, BC, Canada V6T 1Z4.
Waste Manag. 2007;27(7):932-45. doi: 10.1016/j.wasman.2006.04.014. Epub 2007 Jan 26.
In Japan the volume of municipal solid waste is reduced by incineration, with fly ash and bottom ash disposed in controlled landfills. The leachability of anions and heavy metal cations, Zn, Cu and Pb, from MSW fly ash and bottom ash at different pHs was examined using batch- and column-leaching tests. The MSW ashes had a high capacity for neutralizing acids. Behaviour during leaching depended on the pH of the solution. For the volumes applied, the leachabilities of MSW fly ash were very similar at pHs from 3 to 6. Due to its amphoteric nature, Pb is leachable at pHs of approximately 10 or more, with leachate concentrations of about 3 and 3-10mg/L for the fly ash and bottom ash, respectively, much higher than for Zn and Cu. Pb concentrations for most leaching solutions were 1 and 3mg/L for the fly ash and bottom ash, respectively. Zn, and Cu leached at low concentrations for solutions of pH 3-6. Na and K ions leached at high concentrations of approximately 5000 mg/L in the first batch leaching test, decreasing to 10mg/L by the fourth leach. Ca and Mg ions leached more gradually than Na and K. Cl(-) and SO(4)(2+) ions were the major anions in the MSW ash. The high pH and cation leaching are expected to have negative impacts on the performance of clay liners.
在日本，城市固体废物通过焚烧进行减量处理，飞灰和底灰则被放置在受控填埋场中。采用批量浸出试验和柱浸出试验，研究了不同pH值下城市固体废弃物飞灰和底灰中阴离子以及重金属阳离子锌、铜和铅的浸出性。城市固体废弃物灰具有较高的中和酸的能力。浸出过程中的行为取决于溶液的pH值。在所施加的体积范围内，城市固体废弃物飞灰在pH值为3至6时的浸出性非常相似。由于铅具有两性性质，在pH值约为10或更高时可被浸出，飞灰和底灰的浸出液浓度分别约为3mg/L和3 - 10mg/L，远高于锌和铜。大多数浸出液中飞灰和底灰的铅浓度分别为1mg/L和3mg/L。在pH值为3 - 6的溶液中，锌和铜的浸出浓度较低。在第一批浸出试验中，钠和钾离子以约5000mg/L的高浓度浸出，到第四次浸出时降至10mg/L。钙和镁离子的浸出比钠和钾更缓慢。氯离子和硫酸根离子是城市固体废弃物灰中的主要阴离子。高pH值和阳离子浸出预计会对黏土衬层的性能产生负面影响。
