Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China.
Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China; Institute of Eco-Chongming, East China Normal University, Shanghai, China.
Environ Int. 2019 Apr;125:142-151. doi: 10.1016/j.envint.2019.01.060. Epub 2019 Feb 1.
Three-dimensional biofilm electrode reactors (3D-BERs) represent a novel technology for wastewater denitrification. Formation of mature electroactive biofilm on particle electrodes is crucial to realize successful denitrification in 3D-BERs. However, long start-up time and low electroactivity of the biofilm formed on particle electrodes limit the further application of 3D-BERs in wastewater treatment. In this work, self-assembled hybrid biofilms (SAHB) was cultivated on granular activate carbon particle electrodes of the 3D-BER by assembling nano ɑ-FeO into the biofilm. ɑ-FeO was selected due to its high affinity to bacterial outer-membrane cytochromes, an important mediator for microbial electron transfer. SAHB formed on particle electrodes were characterized and the denitrification performance of 3D-BERs was also investigated. Results indicate that nano ɑ-FeO plays positive roles in the start-up of 3D-BER, which captures more microbes into SAHB and constructs thick biofilm on particle electrodes. Special microorganisms with denitrification function related with genera of Hydrogenophaga and Opitutus are distinctively enriched in SAHB. Nano ɑ-FeO induced SAHB exhibit superior denitrification performance compared to natural biofilm. The average denitrification rate increases from 0.62 mg total nitrogen/L/h for natural biofilm to 1.73 mg total nitrogen/L/h for SAHB, mainly ascribed to accelerated nitrites reduction. Our work provides new technical solution to enhance nitrates removal in 3D-BERs and brings deep insights into application of bio-electrochemical system in wastewater treatment.
三维生物膜电极反应器（3D-BER）代表了一种用于废水脱氮的新型技术。在 3D-BER 中实现成功脱氮的关键是在颗粒电极上形成成熟的电活性生物膜。然而，颗粒电极上形成的生物膜的启动时间长且电活性低，限制了 3D-BER 在废水处理中的进一步应用。在这项工作中，通过将纳米ɑ-FeO 组装到生物膜中，在 3D-BER 的颗粒活性炭颗粒电极上培养了自组装混合生物膜（SAHB）。选择ɑ-FeO 是因为它与细菌外膜细胞色素具有高亲和力，细胞色素是微生物电子转移的重要介质。对电极上形成的 SAHB 进行了表征，并研究了 3D-BER 的脱氮性能。结果表明，纳米ɑ-FeO 在 3D-BER 的启动中发挥了积极作用，它将更多的微生物捕获到 SAHB 中，并在颗粒电极上构建了厚厚的生物膜。与氢噬菌属和卵形菌属等具有脱氮功能的特殊微生物在 SAHB 中明显富集。与天然生物膜相比，纳米ɑ-FeO 诱导的 SAHB 表现出优异的脱氮性能。平均总氮去除率从天然生物膜的 0.62 mg 总氮/L/h 增加到 SAHB 的 1.73 mg 总氮/L/h，主要归因于亚硝酸盐还原的加速。我们的工作为增强 3D-BER 中的硝酸盐去除提供了新的技术解决方案，并为生物电化学系统在废水处理中的应用提供了深入的见解。
