Pegasus Technical Services, Inc., 46 E. Hollister St., Cincinnati, OH, 45219, United States.
U.S. Environmental Protection Agency, National Risk Management Research Laboratory, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, United States.
J Environ Manage. 2018 Dec 1;227:321-328. doi: 10.1016/j.jenvman.2018.08.113. Epub 2018 Sep 7.
Mining-influenced water (MIW) remediation is challenging, not only due to its acidity and high metal content, but also due to its presence in remotely located mine sites with difficult surrounding environments. An alternative to common remediation technologies, is the use of sulfate-reducing bacteria (SRB) to achieve simultaneous sulfate reduction and metal removal in on-site anaerobic passive systems. In these systems, the organic carbon source (substrate) selection is critical to obtaining the desired effluent water quality and a reasonable treated volume. In this study, we evaluated the use of two different substrates: a chitinous product obtained from crushed crab shells, and a more traditional ligneous substrate. We put the substrates, both with and without water pretreatment consisting of aeration and pH adjustment, in anaerobic experimental columns. The treatment with the chitinous substrate was more effective in removing metals (Al, Cu, Fe, Cd, Mn, Zn) and sulfate for a longer period (458 days) than the ligneous substrate (78 days) before suffering Zn breakthrough. The reactors fed with pretreated water had longer operational periods and lower metals and sulfate concentrations in the effluent than those with untreated influent water. Zn was consistently removed to levels <0.3 mg/L for 513 days in the chitinous substrate columns, while levels <0.3 mg/L were maintained for only 140 days in the ligneous substrate pretreated column. The highest sulfate removal rates achieved in this study were in the range of 5-6 mol/m/d for the chitinous substrate and 1-2 mol/m/d for the ligneous substrate. Overall, the chitinous substrate proved to be more efficient in the removal of all the aforementioned metals and for sulfate when compared to the ligneous substrate. This could be the determinant when selecting a substrate for passive systems treating acidic MIW, particularly when Zn and Mn removal is necessary.
受采矿影响的水（MIW）的修复具有挑战性，不仅因为其酸度和高金属含量，还因为它存在于偏远的矿山地点，周围环境恶劣。替代常见修复技术的方法是使用硫酸盐还原菌（SRB）在现场厌氧被动系统中实现同时的硫酸盐还原和金属去除。在这些系统中，有机碳源（底物）的选择对于获得所需的出水水质和合理的处理量至关重要。在这项研究中，我们评估了两种不同的底物的使用效果：一种是从碎蟹壳中获得的壳质产品，另一种是更传统的木质底物。我们将底物（包括未经预处理和经过预处理的）放入厌氧实验柱中。与木质底物相比，壳质底物在更长的时间（458 天）内更有效地去除金属（Al、Cu、Fe、Cd、Mn、Zn）和硫酸盐（458 天），然后才出现 Zn 穿透。用预处理水喂养的反应器比用未处理的进水喂养的反应器具有更长的运行时间和更低的金属和硫酸盐浓度在流出物中。在壳质底物柱中，Zn 持续被去除到 <0.3mg/L 的水平，持续了 513 天，而在木质底物预处理柱中，仅维持了 140 天。本研究中实现的最高硫酸盐去除率在壳质底物的范围内为 5-6mol/m/d，而木质底物的范围为 1-2mol/m/d。总的来说，壳质底物在去除所有上述金属和硫酸盐方面比木质底物更有效。这在选择用于处理酸性 MIW 的被动系统的底物时可能是一个决定因素，特别是当需要去除 Zn 和 Mn 时。
