Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao University of Technology, School of Environmental and Municipal Engineering, Qingdao 266033, China.
Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao University of Technology, School of Environmental and Municipal Engineering, Qingdao 266033, China.
Waste Manag. 2021 Feb 1;120:68-75. doi: 10.1016/j.wasman.2020.11.020. Epub 2020 Dec 4.
Solidification/stabilization pretreatment + landfill disposal in municipal solid waste (MSW) landfill sites is a widely accepted MSW incineration (MSWI) fly ash (FA) management strategy in China. However, in reality, the stability of FA disposed in MSW landfill sites may be affected by the organic landfill leachate environment. The purpose of this study was to explore the mobility and environmental risks of six toxic metals (M, Pb/Zn/Cu/Cd/Cr/Ni), from raw and solidified/stabilized FA, by simulating a leaching environment with mature landfill leachate (MLL). The leaching of M mainly occurred in the early leaching stage, and their leaching behavior was controlled by the diffusion of surface M in the FA matrix. The destructive effect of dissolved organic matter (DOM) on the local precipitation-dissolution equilibrium of FA-leachate interface, the formation of non-adsorptive DOM-M complex (easy to migrate), and the competitive effect of DOM on the binding sites of M on the surface of the FA matrix may play an important role in increasing the leaching level of most M. By contrast, the potential of solidified FA in reducing the environmental risk level of leached M was better than that of stabilized FA. However, the immobilization capability of solidification/stabilization pretreatment on various types of M in FA should be judged according to their practical disposal environment. Compared to MLL leaching tests, Acetic Acid Buffer Solution Method (HJ/T300-2007) can effectively strengthen the exposure environment and provide a reliable reference level of environmental risk for MSWI FA disposed in MSW landfill sites.
固化/稳定化预处理+在生活垃圾填埋场中填埋处置是中国广泛接受的城市固体废物（MSW）焚烧（MSWI）飞灰（FA）管理策略。然而，在实际中，FA 在生活垃圾填埋场中的稳定性可能会受到有机垃圾渗滤液环境的影响。本研究的目的是通过模拟成熟垃圾渗滤液（MLL）浸出环境，探索原始和固化/稳定化 FA 中六种有毒金属（M、Pb/Zn/Cu/Cd/Cr/Ni）的迁移性和环境风险。M 的浸出主要发生在早期浸出阶段，其浸出行为受 FA 基质中表面 M 的扩散控制。溶解有机物（DOM）对 FA-浸出液界面局部沉淀-溶解平衡的破坏作用、非吸附性 DOM-M 配合物（易迁移）的形成以及 DOM 对 FA 基质表面 M 结合位点的竞争作用，可能在增加大多数 M 的浸出水平方面发挥重要作用。相比之下，固化 FA 降低浸出 M 环境风险水平的潜力优于稳定化 FA。然而，固化/稳定化预处理对 FA 中各种 M 的固定能力应根据其实际处置环境进行判断。与 MLL 浸出试验相比，乙酸缓冲溶液法（HJ/T300-2007）可以有效强化暴露环境，为 MSWI FA 在生活垃圾填埋场中的处置提供可靠的环境风险参考水平。
