Selenium pollution in aquatic environments poses a major global challenge, with a significant gap in effective treatment technologies. In this study, we explored a novel approach integrating flow-electrode capacitive deionization (FCDI) with bio-electrochemical systems (BES) for the removal and reduction of selenate and selenite ions in one compact reactor. Our integrated system was electricity-driven, eliminating chemical usage. Up to 76 % selenium removal from the waste streams was achieved, followed by up to 66 % and 54 % reduction of selenate and selenite to elemental selenium respectively. The addition of acetate, a carbon source, enhanced selenate reduction by 14 % but lowered selenite reduction by 21 %, suggesting the substrate-dependent and bio-electrochemical-driven nature of selenate and selenite reduction respectively. Metagenomic sequencing revealed that Geobacter sulfurreducens and Pseudomonas stutzeri two known Se-reducing species, likely contributed to both selenite and selenate reduction through up-regulating functional genes related to sulfide reductase, fumarate reductase, and multi-heme c-type cytochromes. Thauera spp. and Alishewanella spp., two species not previously associated with selenium reduction, were likely involved in selenite reduction via the up-regulation of genes related to sulfite reductase and selenium reductase.

中文翻译：

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通过集成流动电极电容式去离子 （FCDI） 和生物电化学系统 （BES） 进行硒处理


水生环境中的硒污染构成了重大的全球挑战，在有效处理技术方面存在巨大差距。在这项研究中，我们探索了一种将流电极电容式去离子 （FCDI） 与生物电化学系统 （BES） 相结合的新方法，用于在一个紧凑的反应器中去除和还原硒酸盐和亚硒酸盐离子。我们的集成系统由电力驱动，无需使用化学品。从废物流中去除了高达 76% 的硒，其次是将硒酸盐和 亚硒酸盐分别减少高达 66% 和 54% 为元素硒。添加碳源乙酸盐使硒酸盐还原量提高了 14%，但降低了 21% 的亚硒酸盐还原量，这表明亚硒酸盐和亚硒酸盐还原分别具有基质依赖性和生物电化学驱动的性质。宏基因组测序显示，Geobacter sulfurreducens 和 Pseudomonas stutzeri 两种已知的 Se 还原物种，可能通过上调与硫化物还原酶、富马酸盐还原酶和多血红素 c 型细胞色素相关的功能基因，促进了亚硒酸盐和硒酸盐的还原。Thauera spp. 和 Alishewanella spp. 这两个物种以前与硒还原无关，可能通过上调与亚硫酸盐还原酶和硒还原酶相关的基因参与亚硒酸盐还原。