Department of Environmental Microbiology, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany.
Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany.
Microb Biotechnol. 2023 Mar;16(3):595-604. doi: 10.1111/1751-7915.14157. Epub 2022 Oct 19.
Treatment of wastewater contaminated with high sulfate concentrations is an environmental imperative lacking a sustainable and environmental friendly technological solution. Microbial electrochemical technology (MET) represents a promising approach for sulfate reduction. In MET, a cathode is introduced as inexhaustible electron source for promoting sulfate reduction via direct or mediated electron transfer. So far, this is mainly studied in batch mode representing straightforward and easy-to-use systems, but their practical implementation seems unlikely, as treatment capacities are limited. Here, we investigated bioelectrochemical sulfate reduction in flow mode and achieved removal efficiencies (E , 89.2 ± 0.4%) being comparable to batch experiments, while sulfate removal rates (R , 3.1 ± 0.2 mmol L ) and Coulombic efficiencies (CE, 85.2 ± 17.7%) were significantly increased. Different temperatures and hydraulic retention times (HRT) were applied and the best performance was achieved at HRT 3.5 days and 30°C. Microbial community analysis based on amplicon sequencing demonstrated that sulfate reduction was mainly performed by prokaryotes belonging to the genera Desulfomicrobium, Desulfovibrio, and Desulfococcus, indicating that hydrogenotrophic and heterotrophic sulfate reduction occurred by utilizing cathodically produced H or acetate produced by homoacetogens (Acetobacterium). The advantage of flow operation for bioelectrochemical sulfate reduction is likely based on higher absolute biomass, stable pH, and selection of sulfate reducers with a higher sulfide tolerance, and improved ratio between sulfate-reducing prokaryotes and homoacetogens.
处理高硫酸盐浓度污染的废水是一个环境当务之急，但缺乏可持续和环保的技术解决方案。微生物电化学技术（MET）是一种很有前途的硫酸盐还原方法。在 MET 中，阴极作为一种无穷无尽的电子源被引入，通过直接或间接电子转移来促进硫酸盐还原。到目前为止，这主要是在批量模式下进行研究，这种模式代表了简单易用的系统，但由于处理能力有限，它们的实际应用似乎不太可能。在这里，我们研究了流动模式下的生物电化学硫酸盐还原，实现了与批量实验相当的去除效率（E，89.2 ± 0.4%），而硫酸盐去除率（R，3.1 ± 0.2 mmol/L）和库仑效率（CE，85.2 ± 17.7%）则显著提高。我们应用了不同的温度和水力停留时间（HRT），在 HRT 为 3.5 天和 30°C 时达到了最佳性能。基于扩增子测序的微生物群落分析表明，硫酸盐还原主要由属于脱硫微菌属、脱硫弧菌属和脱硫球菌属的原核生物完成，这表明氢营养型和异养型硫酸盐还原是通过利用阴极产生的 H 或同型产乙酸菌（乙酸杆菌）产生的乙酸来进行的。生物电化学硫酸盐还原的流动操作的优势可能基于更高的绝对生物量、稳定的 pH 值、选择具有更高硫化物耐受性的硫酸盐还原菌，以及提高硫酸盐还原菌和同型产乙酸菌之间的比例。
