Laboratory of Environmental Science and Engineering, School of Mining and Metallurgical Engineering, National Technical University of Athens, 9, Iroon Polytechniou St., 15780, Zografou, Greece.
Environ Sci Pollut Res Int. 2018 Dec;25(36):35883-35894. doi: 10.1007/s11356-018-1905-6. Epub 2018 Apr 9.
This work presents and discusses experimental results on the characterisation and metal leaching potential of a biogenic, metal-rich sulphidic sludge, generated in a sulphate-reducing bioreactor, operated to treat acidic synthetic solutions bearing Fe, Zn, Ni and Cu. The sustainability of the metal removal bioprocess strongly depends on the fate of the sludge. To propose appropriate management practices, a detailed characterisation of the sludge is necessary. The granulometry, chemical composition and mineralogy of the sludge were initially determined. The mobility of the metals was assessed via a modified Tessier experimental procedure. The leachability of the sludge metal content was determined via a standard compliance method (EN 12457-2) and experiments designed to evaluate the effect of pH and time on metal leaching from the sludge. The sludge metal content sums up to 69.5% dw, namely iron (14.8%), zinc (18.7%), nickel (17.7%) and copper (18.2%) and, based on the criteria set by European Union, the sludge is characterised as hazardous and inappropriate for landfilling without any pretreatment. The sludge consists mainly of very fine poorly crystalline aggregates of Fe, Zn, Cu and Ni sulphides. The fine grain size, the poorly crystalline structure and the oxidation of sulphide upon exposure to water/air render the high metal content of the sludge recoverable.
本工作介绍并讨论了在硫酸盐还原生物反应器中处理含有 Fe、Zn、Ni 和 Cu 的酸性合成溶液时生成的具有生物成因、富含金属的硫化物污泥的特性和金属浸出潜力的实验结果。金属去除生物工艺的可持续性强烈依赖于污泥的命运。为了提出适当的管理实践，需要对污泥进行详细的特性描述。首先确定了污泥的粒度、化学组成和矿物学。通过改进的 Tessier 实验程序评估了金属的迁移性。通过标准合规方法（EN 12457-2）和旨在评估 pH 值和时间对污泥中金属浸出影响的实验确定了污泥金属含量的浸出性。污泥金属含量总计为 69.5%（干重），即铁（14.8%）、锌（18.7%）、镍（17.7%）和铜（18.2%），根据欧盟设定的标准，污泥具有危害性，未经任何预处理不适合填埋。污泥主要由 Fe、Zn、Cu 和 Ni 硫化物的非常细的非晶态细颗粒组成。细颗粒尺寸、非晶态结构以及暴露于水/空气中时硫化物的氧化使高金属含量的污泥可回收。
