School of Chemistry & Environment, South China Normal University, Guangzhou, China.
School of Chemistry & Environment, South China Normal University, Guangzhou, China; Department of Bioscience, Aarhus University, Aarhus, Denmark.
Water Res. 2018 Mar 15;131:239-245. doi: 10.1016/j.watres.2017.12.039. Epub 2017 Dec 22.
Biological sulfur reduction can theoretically produce sufficient sulfide to effectively remove and recover heavy metals in the treatment of organics-deficient sulfate-rich metal-laden wastewater such as acid mine drainage and metallurgic wastewater, using 75% less organics than biological sulfate reduction. However, it is still unknown whether sulfur reduction can indeed compete with sulfate reduction, particularly under high-strength sulfate conditions. The aim of this study was to investigate the long-term feasibility of biological sulfur reduction under high sulfate conditions in a lab-scale sulfur-reducing biological sulfide production (BSP) system with sublimed sulfur added. In the 169-day trial, an average sulfide production rate (SPR) as high as 47 ± 9 mg S/L-h was achieved in the absence of sulfate, and the average SPR under sulfate-rich conditions was similar (53 ± 10 mg S/L-h) when 1300 mg S/L sulfate were fed with the influent. Interestingly, sulfate was barely reduced even at such a high strength and contributed to only 1.5% of total sulfide production. Desulfomicrobium was identified as the predominant sulfidogenic bacterium in the bioreactor. Batch tests further revealed that this sulfidogenic bacteria used elemental sulfur as the electron acceptor instead of the highly bioavailable sulfate, during which polysulfide acted as an intermediate, leading to an even higher bioavailability of sulfur than sulfate. The pathway of sulfur to sulfide conversion via polysulfide in the presence of both sulfur and sulfate was discussed. Collectively, when conditions favor polysulfide formation, sulfur reduction can be a promising and attractive technology to realize a high-rate and low-cost BSP process for treating sulfate-rich metal-laden wastewater.
生物硫还原理论上可以产生足够的硫化物，有效去除和回收贫有机物、富含硫酸盐的重金属，例如酸性矿山排水和冶金废水，与生物硫酸盐还原相比，其所需有机物用量减少 75%。然而，硫还原是否真的能与硫酸盐还原竞争，特别是在高强度硫酸盐条件下，目前仍不得而知。本研究旨在通过添加升华硫的实验室规模硫还原生物硫化物生产（BSP）系统，研究在高硫酸盐条件下长期进行生物硫还原的可行性。在 169 天的试验中，在没有硫酸盐的情况下，实现了高达 47±9mgS/L-h 的平均硫化物生成速率（SPR），而在 1300mgS/L 硫酸盐作为进水进料的富硫酸盐条件下，平均 SPR 相似（53±10mgS/L-h）。有趣的是，即使硫酸盐强度如此之高，硫酸盐的还原也几乎没有，仅贡献了总硫化物生成量的 1.5%。脱硫微菌被鉴定为生物反应器中主要的产硫化物细菌。批处理试验进一步表明，这种产硫化物细菌将元素硫作为电子受体，而不是高生物利用性的硫酸盐，在此过程中多硫化物作为中间产物，导致硫的生物利用度甚至高于硫酸盐。讨论了在同时存在硫和硫酸盐的情况下，通过多硫化物将硫转化为硫化物的途径。总的来说，当条件有利于多硫化物形成时，硫还原可以成为一种有前途和有吸引力的技术，用于实现高效、低成本的 BSP 工艺，以处理富含硫酸盐的重金属废水。
