State Key Laboratory of Microbial Metabolism, and Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
State Key Laboratory of Microbial Metabolism, and Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Chemosphere. 2024 Jun;358:142216. doi: 10.1016/j.chemosphere.2024.142216. Epub 2024 May 3.
As a novel biological wastewater nitrogen removal technology, simultaneous nitrification and denitrification (SND) has gained increasing attention. Iron, serving as a viable material, has been shown to influence nitrogen removal. However, the precise impact of iron on the SND process and microbiome remains unclear. In this study, bioreactors amended with iron of varying valences were evaluated for total nitrogen (TN) removal efficiencies under aerobic conditions. The acclimated control reactor without iron addition (NCR) exhibited high ammonia nitrogen (AN) removal efficiency (98.9%), but relatively low TN removal (78.6%) due to limited denitrification. The reactor containing zero-valent iron (Fe0R) demonstrated the highest SND rate of 92.3% with enhanced aerobic denitrification, albeit with lower AN removal (84.1%). Significantly lower SND efficiencies were observed in reactors with ferrous (Fe2R, 66.3%) and ferric (Fe3R, 58.2%) iron. Distinct bacterial communities involved in nitrogen metabolisms were detected in these bioreactors. The presence of complete ammonium oxidation (comammox) genus Nitrospira and anammox bacteria Candidatus Brocadia characterized efficient AN removal in NCR. The relatively low abundance of aerobic denitrifiers in NCR hindered denitrification. Fe0R exhibited highly abundant but low-efficiency methanotrophic ammonium oxidizers, Methylomonas and Methyloparacoccus, along with diverse aerobic denitrifiers, resulting in lower AN removal but an efficient SND process. Conversely, the presence of Fe/Fe constrained the denitrifying community, contributing to lower TN removal efficiency via inefficient denitrification. Therefore, different valent irons modulated the strength of nitrification and denitrification through the assembly of key microbial communities, providing insight for microbiome modulation in nitrogen-rich wastewater treatment.
作为一种新型的生物废水脱氮技术，同步硝化反硝化（SND）受到了越来越多的关注。铁作为一种可行的材料，已被证明对氮的去除有影响。然而，铁对 SND 过程和微生物组的精确影响仍不清楚。在这项研究中，评估了不同价态的铁对好氧条件下总氮（TN）去除效率的影响。未添加铁的驯化对照反应器（NCR）表现出高氨氮（AN）去除效率（98.9%），但由于有限的反硝化作用，TN 去除率相对较低（78.6%）。含有零价铁（Fe0R）的反应器表现出最高的 SND 率（92.3%），增强了好氧反硝化作用，但 AN 去除率较低（84.1%）。含有二价铁（Fe2R）和三价铁（Fe3R）的反应器的 SND 效率明显较低。这些生物反应器中检测到参与氮代谢的不同细菌群落。在 NCR 中存在完全氨氧化（comammox）属 Nitrospira 和厌氧氨氧化菌 Candidatus Brocadia，这是 AN 去除效率高的特征。NCR 中好氧反硝化菌的相对低丰度阻碍了反硝化作用。Fe0R 表现出高度丰富但效率较低的甲烷氧化氨氧化菌 Methylomonas 和 Methyloparacoccus，以及多种好氧反硝化菌，导致 AN 去除率较低，但 SND 过程高效。相反，Fe/Fe 的存在限制了反硝化群落，导致 TN 去除效率较低，原因是反硝化作用效率低下。因此，不同价态的铁通过关键微生物群落的组装调节硝化和反硝化的强度，为富含氮的废水处理中的微生物组调节提供了见解。
