Abstract：
Bio-electrochemical systems (BESs) have recently been proposed as an efficient treatment technology to remove organic micropollutants from water treatment plants. In this study, we aimed to differentiate between sorption, electrochemical transport/degradation, and biodegradation. Using electro-active microorganisms and electrodes, we investigated organic micropollutant removal at environmentally relevant concentrations, clarifying the roles of sorption and electrochemical and biological degradation. The role of anodic biofilms on the removal of 10 relevant organic micropollutants was studied by performing separate sorption experiments on carbon-based electrodes (graphite felt, graphite rod, graphite granules, and granular activated carbon) and electrochemical degradation experiments at two different electrode potentials (-0.3 and 0 V). Granular activated carbon showed the highest sorption of micropollutants; applying a potential to graphite felt electrodes increased organic micropollutant removal. Removal efficiencies >80 % were obtained for all micropollutants at high anode potentials (+0.955 V), indicating that the studied compounds were more susceptible to oxidation than to reduction. All organic micropollutants showed removal when under bio-electrochemical conditions, ranging from low (e.g. metformin, 9.3 %) to exceptionally high removal efficiencies (e.g. sulfamethoxazole, 99.5 %). The lower removal observed under bio-electrochemical conditions when compared to only electrochemical conditions indicated that sorption to the electrode is key to guarantee high electrochemical degradation. The detection of transformation products of chloridazon and metformin indicated that (bio)-electrochemical degradation occurred. This study confirms that BES can treat some organic micropollutants through several mechanisms, which merits further investigation.
摘要：
最近提出了生物电化学系统（BES）作为一种有效的处理技术，可从水处理厂中去除有机微污染物。在这项研究中,我们的目的是区分吸附，电化学传输/降解，和生物降解。使用电活性微生物和电极，我们研究了在环境相关浓度下有机微污染物的去除，阐明吸附和电化学和生物降解的作用。通过在碳基电极（石墨毡，石墨棒,石墨颗粒，和颗粒活性炭）以及在两个不同电极电位（-0.3和0V）下的电化学降解实验。颗粒活性炭对微污染物的吸附最高；在石墨毡电极上施加电势可提高有机微污染物的去除率。在高阳极电位（0.955V）下，所有微污染物的去除效率均>80％，这表明所研究的化合物更容易氧化而不是还原。在生物电化学条件下，所有有机微污染物均显示出去除效果，范围从低(例如二甲双胍，9.3%)至异常高的去除效率(例如磺胺甲恶唑，99.5%）。当与仅电化学条件相比时,在生物电化学条件下观察到的较低去除表明吸附到电极是保证高电化学降解的关键。氯硝唑和二甲双胍转化产物的检测表明发生了（生物）电化学降解。这项研究证实了BES可以通过几种机制处理一些有机微污染物，值得进一步调查。
