Environment Research Institute, Shandong University, Jinan 250100, China.
Environment Research Institute, Shandong University, Jinan 250100, China.
Sci Total Environ. 2021 May 20;770:144761. doi: 10.1016/j.scitotenv.2020.144761. Epub 2021 Jan 23.
Intensified Mn redox cycling could enhance nutrient removal in constructed wetlands (CWs). In this study, Mn oxides (birnessite-coated sand) were used as the matrix in horizontal flow CWs (HFCWs) with a microbial electrolysis cell (MEC) (E-B-CW) or without an MEC (B-CW). The model CWs were developed to investigate the capacities and mechanisms of nitrogen removal with increased Mn redox cycling. The results showed that E-B-CW had the highest average removal efficiencies for NH-N, NO-N and TN, followed by B-CW and control HFCW (C-CW). The Mn(III) oxides (MnOOH or MnO) and the Mn(IV) oxide (MnO) were all detected in E-B-CW and B-CW, while the matrix in E-B-CW had much more Mn(IV) oxides than B-CW. Interestingly, clustering heat map showed that ammonification and nitrate reduction were related to Mn-oxidizing bacteria and the relative abundance of Mn-oxidizing bacteria in E-B-CW was highest due to the re-oxidation of Mn(II) by the MEC.
强化锰的氧化还原循环可以增强人工湿地（CWs）中的营养物质去除。在这项研究中，使用了锰氧化物（覆盖有钠锰矿的砂）作为水平流人工湿地（HFCWs）的基质，其中一个带有微生物电解池（MEC）（E-B-CW），另一个没有（B-CW）。该模型 CWs 被开发用于研究通过增加锰的氧化还原循环来提高氮去除能力和机制。结果表明，E-B-CW 对 NH-N、NO-N 和 TN 的平均去除效率最高，其次是 B-CW 和对照水平流人工湿地（C-CW）。在 E-B-CW 和 B-CW 中都检测到了 Mn(III)氧化物（MnOOH 或 MnO）和 Mn(IV)氧化物（MnO），而 E-B-CW 的基质中 Mn(IV)氧化物的含量比 B-CW 高得多。有趣的是，聚类热图显示氨化和硝酸盐还原与锰氧化菌有关，由于 MEC 对 Mn(II)的再氧化，E-B-CW 中锰氧化菌的相对丰度最高。
