城市生活垃圾焚烧飞灰物化性质及重金属污染特性

The physiochemical properties and heavy metal pollution of fly ash from municipal solid waste incineration

以上海市生活垃圾焚烧飞灰为案例,研究了其物化性质及重金属污染特性。结果表明:(1)飞灰孔隙率较高,经化学药剂稳定后飞灰形貌呈致密化,可大大减少重金属浸出;飞灰吸脱附曲线有明显滞回环,属于H2型滞回环,属于典型的多孔物质吸附类型。(2)飞灰重金属的浸出毒性表明,Pb、Cd超出了《生活垃圾填埋场污染控制标准》(GB 16889—2008)中的限值,根据《危险废物鉴别标准浸出毒性鉴别》(GB 5085.3—2007),飞灰属于危险废物。(3)在酸性条件下,重金属较易释放到环境中。

The physiochemical properties of fly ash derived from domestic waste incineration were measured as well as the leaching toxicity of heavy metals contained in fly ash. The results suggested that the leaching concentration of heavy metals could be greatly reduced through densification strategies that fly ash stabilized by chemical agents. The adsorption/desorption curve of fly ash had an obvious hysteresis loop that belonged to the H2-type hysteresis loop. Pb and Cd exceeded the limit of “Standard for pollution control on the landfill site of municipal solid waste” （ GB 16889-2008）. According to “Identification standards for hazardous wastes - identification for extraction toxicity” （ GB 5085.3-2007）,fly ash was hazardous waste. Heavy metals were easily leached out under strong acid or alkaline conditions.