Toledo-Alarcón Javiera, Ortega-Martinez Eduardo, Pavez-Jara Javier, Franchi Oscar, Nancucheo Ivan, Zuñiga-Barra Héctor, Campos Jose Luis, Jeison David
Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Viña del Mar, Chile.
Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.
Front Bioeng Biotechnol. 2025 Jan 22;13:1475589. doi: 10.3389/fbioe.2025.1475589. eCollection 2025.
Nitrate, a major groundwater pollutant from anthropogenic activities, poses serious health risks when present in drinking water. Denitrification using bio-electrochemical reactors (BER) offers an innovative technology, eco-friendly solution for nitrate removal from groundwater. BER use electroactive bacteria to reduce inorganic compounds like nitrate and bicarbonate by transferring electrons directly from the cathode. In our work, two batch BER were implemented at 1V and 2V, using anaerobic digestate from a full-scale wastewater treatment plant as inoculum. Nitrate, nitrite, sulfate, total ammoniacal nitrogen, and 16S rRNA analysis of bacterial community, were monitored during BER operation. The results showed effective nitrate removal in all BERs, with denitrification rate at 1V and 2V higher than the Control system, where endogenous respiration drove the process. At 1V, complete nitrate conversion to N occurred in 4 days, while at 2V, it took 14 days. The slower rate at 2V was likely due to O production from water electrolysis, which competed with nitrate as final electron acceptor. Bacterial community analysis confirmed the electroactive bacteria selection like the genus and , confirming electrons transfer without an electroactive biofilm. Besides, was enhanced at 2V likely due to electrolytically produced H. Sulfate was not reduced, and total ammoniacal nitrogen remained constant indicating no dissimilatory nitrite reduction of ammonia. These results provide a significant contribution to the scaling up of electro-assisted autotrophic denitrification and its application in groundwater remediation, utilizing a simple reactor configuration-a single-chamber, membrane-free design- and a conventional power source instead of a potentiostat.
硝酸盐是人为活动产生的主要地下水污染物,存在于饮用水中时会带来严重的健康风险。使用生物电化学反应器(BER)进行反硝化提供了一种创新技术,是从地下水中去除硝酸盐的环保解决方案。BER利用电活性细菌通过直接从阴极转移电子来还原硝酸盐和碳酸氢盐等无机化合物。在我们的工作中,使用来自一座全尺寸污水处理厂的厌氧消化液作为接种物,在1V和2V电压下运行了两个批次的BER。在BER运行期间,监测了硝酸盐、亚硝酸盐、硫酸盐、总氨氮以及细菌群落的16S rRNA分析。结果表明,所有BER中硝酸盐去除效果良好,1V和2V电压下的反硝化速率高于控制系统,在控制系统中是内源性呼吸驱动该过程。在1V电压下,4天内硝酸盐完全转化为氮气,而在2V电压下则需要14天。2V电压下速率较慢可能是由于水电解产生的氧气与硝酸盐竞争作为最终电子受体。细菌群落分析证实了对电活性细菌如属和属的选择,证实了电子转移无需电活性生物膜。此外,2V电压下可能由于电解产生的氢气而增强。硫酸盐未被还原,总氨氮保持恒定,表明不存在氨的异化亚硝酸盐还原。这些结果为扩大电辅助自养反硝化规模及其在地下水修复中的应用做出了重大贡献,采用了简单的反应器配置——单室、无膜设计——以及传统电源而非恒电位仪。