Centre for Solid Waste Bioprocessing, Schools of Civil and Chemical Engineering, The University of Queensland, St. Lucia, Brisbane 4072, Australia.
School of Civil Engineering, The University of Queensland, St. Lucia, Brisbane 4072, Australia.
J Hazard Mater. 2015 Dec 15;299:577-83. doi: 10.1016/j.jhazmat.2015.07.065. Epub 2015 Jul 28.
Heavy metals present in landfill leachate have infrequently been related to complete anaerobic degradation municipal solid waste (MSW) due to discrete ages of deposited MSW layers and leachate channelling in landfills. In this study, anaerobic digestion of MSW was performed in two enclosed 1000 tonne bioreactors using a unique flood and drain process. Leachates were characterised in terms of pH, soluble chemical oxygen demand, volatile fatty acids (VFAs), ammonium nitrogen and heavy metals over the entire course of digestion. All parameters, including pH, fluctuated during acidogenesis, acetogenesis and methanogenesis, which strongly impacted on the dynamics of dissolved heavy metal concentrations. The simulation of dissolution and precipitation processes indicated that metal sulphide precipitation was not a factor as metal concentrations exceeded solubility limits. The correlation of pH and dissolved heavy metal concentrations indicated that other, mechanisms were involved in the homogenised conditions within the bioreactors. Beside dissolution and precipitation, the main processes most likely involved in metal distributions were adsorption (Zn, Cu, Ni, Pb and Cd), complexation (Cr) or combinations of both process (As and Co).
由于填埋场中沉积的 MSW 层的离散年龄和渗滤液的通道化，垃圾渗滤液中的重金属很少与完全厌氧降解城市固体废物 (MSW) 有关。在这项研究中，使用独特的淹没和排水过程，在两个封闭的 1000 吨生物反应器中进行了 MSW 的厌氧消化。在整个消化过程中，根据 pH 值、可溶性化学需氧量、挥发性脂肪酸 (VFAs)、氨氮和重金属对渗滤液进行了表征。包括 pH 值在内的所有参数在产酸、产乙酸和产甲烷过程中均有波动，这强烈影响了溶解重金属浓度的动态变化。溶解和沉淀过程的模拟表明，由于金属浓度超过了溶解度极限，金属硫化物的沉淀不是一个因素。pH 值与溶解态重金属浓度的相关性表明，在生物反应器内的均匀条件下，还涉及其他机制。除了溶解和沉淀之外，金属分布的主要过程很可能涉及吸附（Zn、Cu、Ni、Pb 和 Cd）、络合（Cr）或两者的组合（As 和 Co）。
