Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
Water Res. 2022 May 15;215:118232. doi: 10.1016/j.watres.2022.118232. Epub 2022 Feb 25.
The lack of dissolved oxygen and weak substrate removal capacity in constructed wetlands (CW) leads to terrible removal of nitrogen and polycyclic aromatic hydrocarbons (PAHs). In this study, automatic tidal flow CW microcosms were constructed by improving the oxygen environment (siphon and air-duct) and substrate (magnetite) to enhance purification performance and the mechanism was explored. The results showed that the addition of air-duct could improve the oxygen collection and thus improved the NH removal efficiency. Additionally, nitrogen removal was improved greatly due to the simultaneous nitrification and denitrification in aerobic layer with the addition of magnetite. Mass balance indicated the microbial degradation dominated (32-62%) the removal of PAHs. Metagenomic analysis proved the existence of magnetite enhanced the number of PAHs-degrading bacteria, functional groups and metabolic pathways and thus greatly improved the microbial degradation of PAHs. Furthermore, Fe/Fe cycle played an important role in promoting the anaerobic degradation of PAHs, which might be served as an electron conduit to establish the direct interspecies electron transfer between iron-reducing bacteria (e.g. Deltaproteobacteria bacterium) and Anaerolineae bacterium to degrade PAHs efficiently. This study provided better understanding of the simultaneous removal of PAHs and nitrogen in tidal flow CWs.
人工湿地（CW）中溶解氧缺乏和基质去除能力较弱，导致氮和多环芳烃（PAHs）的去除效果不佳。本研究通过改善氧环境（虹吸和空气管道）和基质（磁铁矿）来构建自动潮汐流 CW 微系统，以提高净化性能，并探讨了其机制。结果表明，空气管道的添加可以提高氧气收集效率，从而提高 NH 的去除效率。此外，由于磁铁矿的添加，好氧层中同时发生硝化和反硝化作用，从而大大提高了氮的去除效率。质量平衡表明，微生物降解（32-62%）主导了 PAHs 的去除。宏基因组分析证明了磁铁矿的存在增强了 PAHs 降解菌、功能群和代谢途径的数量，从而大大提高了 PAHs 的微生物降解。此外，Fe/Fe 循环在促进 PAHs 的厌氧降解中起着重要作用，它可能作为电子导体能在铁还原菌（例如δ变形菌）和产甲烷菌之间建立直接的种间电子转移，从而有效地降解 PAHs。本研究为潮汐流 CW 中同时去除 PAHs 和氮提供了更好的理解。
