Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan.
Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan.
Chemosphere. 2021 Jul;274:129715. doi: 10.1016/j.chemosphere.2021.129715. Epub 2021 Jan 23.
Nitrogen removal from wastewater is an indispensable but highly energy-demanding process, and thus more energy-saving treatment processes are required. Here, we investigated the performance of bioelectrochemical ammonium nitrogen (NH-N) removal from real domestic wastewater without energy-intensive aeration by a single chamber microbial electrolysis cell (MEC) that was electrically powered by a double chamber microbial fuel cell (MFC). Anoxic NH-N oxidation and total nitrogen (TN) removal rates were determined at various applied voltages (0-1.2 V), provided by the MFC. The MEC achieved a NH-N oxidation rate of 151 ± 42 g NH-N m d and TN removal rate of 95 ± 42 g-TN m d without aeration at the applied voltage of 0.8 V (the anode potential E = +0.633 ± 0.218 V vs. SHE). These removal rates were much higher than the previously reported values and conventional biological nitrogen removal processes. Open and closed-circuit MEC batch experiments confirmed that anoxic NH-N oxidation was an electrochemically mediated biological process (that is, an anode acted as an electron acceptor) and denitrification occurred simultaneously without NO and NO accumulation. Moreover, ex-situN tracer experiment and microbial community analysis revealed that anammox and heterotrophic denitrification mainly contributed to the TN removal. Thus, the bioelectrochemical anodic NH-N oxidation was coupled with anammox and denitrification in this MFC-assisted MEC system. Taken together, our MFC-driven single chamber MEC could be a high rate energy-saving nitrogen removal process without external carbon and energy input and high energy-demanding aeration.
从废水中去除氮是一个不可或缺但高度耗能的过程，因此需要更节能的处理工艺。在这里，我们研究了通过单室微生物电解池（MEC）在没有能源密集型曝气的情况下从实际生活废水中去除生物电化学铵氮（NH-N）的性能，该 MEC 通过双室微生物燃料电池（MFC）提供电力。在各种施加电压（0-1.2 V）下，确定了缺氧 NH-N 氧化和总氮（TN）去除率，由 MFC 提供。在 0.8 V 的施加电压下（阳极电位 E = +0.633 ± 0.218 V 对 SHE），MEC 无需曝气即可实现 151 ± 42 g NH-N m d 的 NH-N 氧化速率和 95 ± 42 g-TN m d 的 TN 去除率。这些去除率远高于先前报道的值和传统的生物脱氮工艺。开环和闭环 MEC 批量实验证实，缺氧 NH-N 氧化是一种电化学介导的生物过程（即，阳极充当电子受体），同时发生反硝化作用，而没有 NO 和 NO 积累。此外，异位 N 示踪实验和微生物群落分析表明，厌氧氨氧化和异养反硝化主要有助于 TN 的去除。因此，在这种 MFC 辅助 MEC 系统中，生物电化学阳极 NH-N 氧化与厌氧氨氧化和反硝化耦合。总之，我们的 MFC 驱动的单室 MEC 可以是一种无需外部碳和能源输入以及高能耗曝气的高效节能脱氮工艺。
