Hyks Jiri, Astrup Thomas, Christensen Thomas H
DTU Environment, Technical University of Denmark, Department of Environmental Engineering, Miljøvej B113, 2800 Kgs.Lyngby, Denmark.
Waste Manag. 2009 Feb;29(2):522-9. doi: 10.1016/j.wasman.2008.06.011. Epub 2008 Aug 5.
Impacts of non-equilibrium on results of percolation experiments on municipal solid waste incineration (MSWI) bottom ash were investigated. Three parallel column experiments were performed: two columns with undisturbed percolation and one column with two sets of 1-month-long flow interruptions applied at liquid-to-solid (L/S) ratios of L/S 2L/kg and 12L/kg, respectively. Concentrations of Na, K, Cl(-), Ca, Si, SO(4)(2-), Al, Cu, Ni, Mo, Ba, Pb, Zn, and dissolved organic carbon (DOC) were monitored throughout the entire leaching period; geochemical modeling was used to identify non-equilibrium-induced changes in the solubility control. Despite both physical and chemical non-equilibrium, the columns were found to provide adequate information for readily soluble compounds (i.e., Na, Cl(-), and K) and solubility-controlled elements (i.e., Ca, SO(4)(2-), Ba, Si, Al, Zn, and Pb). The leaching of Cu and Ni was shown to depend strongly on DOC leaching, which was likely affected by physical non-equilibrium during flow interruptions. Consequently, the leaching of Cu and Ni in the undisturbed columns was shown to be by about one order of magnitude lower compared with the interrupted column. The results indicate that the leaching of DOC-related metals in laboratory column experiments may be considerably underestimated compared with full-scale scenarios in which the impacts from non-equilibrium may be significantly lower. The leaching of Mo (or MoO(4)(2-)) may be controlled solely by its availability in the mobile zone, which in turn appeared to be controlled by diffusion from the stagnant zone; no Mo controlling minerals were predicted by the geochemical modeling.
研究了非平衡对城市固体废物焚烧（MSWI）底灰渗滤实验结果的影响。进行了三个平行柱实验：两个柱进行无干扰渗滤，一个柱在液固比（L/S）分别为2L/kg和12L/kg时施加两组为期1个月的流中断。在整个浸出期间监测了Na、K、Cl⁻、Ca、Si、SO₄²⁻、Al、Cu、Ni、Mo、Ba、Pb、Zn和溶解有机碳（DOC）的浓度；使用地球化学模型来识别非平衡引起的溶解度控制变化。尽管存在物理和化学非平衡，但发现这些柱为易溶化合物（即Na、Cl⁻和K）和溶解度控制元素（即Ca、SO₄²⁻、Ba、Si、Al、Zn和Pb）提供了足够的信息。结果表明，Cu和Ni的浸出强烈依赖于DOC浸出，这可能受到流中断期间物理非平衡的影响。因此，与中断柱相比，未受干扰柱中Cu和Ni的浸出量低约一个数量级。结果表明，与非平衡影响可能显著较低的全尺寸场景相比，实验室柱实验中与DOC相关金属的浸出可能被大大低估。Mo（或MoO₄²⁻）的浸出可能仅由其在流动区的可用性控制，而流动区的可用性又似乎由来自停滞区的扩散控制；地球化学模型未预测到控制Mo的矿物。
