Wang Yue, Bai Yihan, Xu Liang, Su Junfeng, Ren Miqi, Hou Chenxi, Feng Jingting
School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
Environ Res. 2025 Mar 1;268:120778. doi: 10.1016/j.envres.2025.120778. Epub 2025 Jan 5.
Manganese(IV) (Mn(IV)) reduction coupled with ammonium (NH-N) oxidation (Mnammox) has been found to play a significant role in the nitrogen (N) cycle within natural ecosystems. However, research and application of the autotrophic NH-N removal process mediated by manganese oxides (MnOx) in wastewater treatment are currently limited. This study established autotrophic NH-N removal sludge reactors mediated by various MnOx types, including δ-MnO (δ-MSR), β-MnO (β-MSR), α-MnO (α-MSR), and natural Mn ore (MOSR), investigating their NH-N removal performances and mechanisms under different initial N loading and pH conditions. During the 330 d operation, the reactors exhibited NH-N removal efficiencies in the order of δ-MSR > α-MSR > β-MSR > MOSR. Notably, metal-reducing bacteria (Candidatus Brocadia, Dechloromonas, and Rhodocyclaceae) and Mn(II) oxidizing bacteria (Pseudomonas and Zoogloea) were enriched in the reactors, especially in the δ-MSR. The presence of these microorganisms facilitated the reduction of Mn(IV) and utilized the generated Mn(II) to drive autotrophic denitrification (MnOAD), thereby completing the Mn(IV)/Mn(II) cycle and enhancing N removal in the system. An active Mn cycle displayed in δ-MSR, which could be demonstrated by the formation of petal-shaped biogenic MnOx and the increased abundance of Mn cycling genes (MtrCDE, MtrA, MtrB, and CotA, etc.). Meanwhile, genes involved in N metabolism were enriched, particularly functional genes associated with nitrification and denitrification. In this study, the coupling of Mnammox and MnOAD was realized via the Mn cycle, providing a new perspective on the application of autotrophic N removal technologies in wastewater treatment.
已发现锰（IV）（Mn（IV））还原与铵（NH-N）氧化耦合（锰氨氧化）在自然生态系统的氮（N）循环中发挥重要作用。然而，目前锰氧化物（MnOx）介导的自养NH-N去除工艺在废水处理中的研究和应用有限。本研究建立了由各种MnOx类型介导的自养NH-N去除污泥反应器，包括δ-MnO（δ-MSR）、β-MnO（β-MSR）、α-MnO（α-MSR）和天然锰矿石（MOSR），研究了它们在不同初始氮负荷和pH条件下的NH-N去除性能及机制。在330天的运行过程中，反应器的NH-N去除效率顺序为δ-MSR > α-MSR > β-MSR > MOSR。值得注意的是，金属还原菌（Candidatus Brocadia、Dechloromonas和红环菌科）和Mn（II）氧化菌（假单胞菌属和动胶菌属）在反应器中富集，尤其是在δ-MSR中。这些微生物的存在促进了Mn（IV）的还原，并利用生成的Mn（II）驱动自养反硝化（MnOAD），从而完成Mn（IV）/Mn（II）循环并提高系统中的氮去除率。δ-MSR中显示出活跃的锰循环，这可以通过花瓣状生物成因MnOx的形成以及锰循环基因（MtrCDE、MtrA、MtrB和CotA等）丰度的增加来证明。同时，参与氮代谢的基因也得到了富集，特别是与硝化和反硝化相关的功能基因。在本研究中，通过锰循环实现了锰氨氧化和MnOAD的耦合，为自养氮去除技术在废水处理中的应用提供了新的视角。
