垃圾焚烧飞灰及其固化/稳定化产物的重金属污染特征及环境风险评估

Pollution Characterization and Environmental Risk Assessment of Heavy Metal of Waste Incineration Fly Ash and its Solidified/Stabilized Products

垃圾焚烧飞灰的无害化处置是垃圾焚烧污染控制的关键环节。选取典型垃圾焚烧厂的飞灰及其固化/稳定化产物,对比分析飞灰固化/稳定化前后的重金属含量、形态、浸出特性及微观形貌的变化,同时采用潜在环境风险评价法和环境风险指数法来评估固化/稳定化处理前后重金属的污染风险差异。结果表明:重庆市垃圾焚烧飞灰中Zn、Pb和Cu含量较高,尤其是Pb的浸出毒性达到标准限值的80.8倍,且Pb、Cu、Zn、As和Hg显示出较强的迁移性;固化/稳定化处理显著降低了重金属的浸出毒性和迁移性,但Pb的浸出毒性仍超标;环境风险评估表明,固化/稳定化处理后飞灰的环境污染风险显著降低,但Pb和Cd的处理效果仍需改进。研究成果可为飞灰处置技术优化提供重要数据支撑。

The harmless disposal of waste incineration fly ash is the key link in the pollution control of waste incineration.Fly ash and its solidification/stabilization products from typical waste incineration plants were selected to compare and analyze the changes of heavy metal content,morphology,leaching characteristics and micro-morphology of fly ash before and after solidification/stabilization.Meanwhile,the potential risk evaluation method and environmental risk index method were used to evaluate the pollution risk differences of heavy metals before and after solidification/stabilization treatment.The results showed that the content of Zn,Pb and Cu in fly ash from waste incineration in Chongqing was high,especially the leaching toxicity of Pb reached 80.8 times of the standard limit value,and the migration of Pb,Cu,Zn,As and Hg was strong.Solidification/stabilization treatment significantly reduced the leaching toxicity and mobility of heavy metals,but the leaching toxicity of Pb still exceeded the standard.The results of the environmental pollution risk suggested that the environmental pollution risk of fly ash after solidification/stabilization treatment was significantly reduced,but the treatment effect of Pb and Cd still needs to be improved.The research results could provided crucial data support for the optimization of fly ash disposal technology.