School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Department of Civil and Environmental Engineering, Northeastern University, Boston, Massachusetts 02115, United States.
Environ Sci Technol. 2024 Jul 23;58(29):13023-13034. doi: 10.1021/acs.est.4c04375. Epub 2024 Jul 13.
Leveraging comammox and anammox bacteria for shortcut nitrogen removal can drastically lower the carbon footprint of wastewater treatment facilities by decreasing aeration energy, carbon, alkalinity, and tank volume requirements while also potentially reducing nitrous oxide emissions. However, their co-occurrence as dominant nitrifying bacteria is rarely reported in full-scale wastewater treatment. As a result, there is a poor understanding of how operational parameters, in particular, dissolved oxygen, impact their activity and synergistic behavior. Here, we report the impact of dissolved oxygen concentration (DO = 2, 4, 6 mg/L) on the microbial community's transcriptomic expression in a full-scale integrated fixed film activated sludge (IFAS) municipal wastewater treatment facility where nitrogen removal is predominantly performed by comammox and anammox bacterial populations. 16S rRNA transcript compositions revealed anammox bacteria and were significantly more active in IFAS biofilms compared to suspended sludge biomass. In IFAS biofilms, anammox bacteria significantly increased expression at lower dissolved oxygen concentrations and this increase was highly correlated with the expression levels of comammox bacteria. Interestingly, the genes involved in nitrite oxidation by comammox bacteria were significantly more upregulated, relative to the genes involved in ammonia oxidation with decreasing dissolved oxygen concentrations. Ultimately, our findings suggest that comammox supplies anammox bacteria with nitrite via ammonia oxidation and that this synergistic behavior is dependent on dissolved oxygen concentrations.
利用 comammox 和 anammox 细菌进行短程脱氮可以大大降低废水处理设施的碳足迹，减少曝气能源、碳、碱度和罐体积的需求，同时还可能减少氧化亚氮的排放。然而，它们作为优势硝化细菌共同存在的情况在全规模废水处理中很少有报道。因此，人们对操作参数（特别是溶解氧）如何影响它们的活性和协同行为知之甚少。在这里，我们报告了溶解氧浓度（DO=2、4、6mg/L）对全规模集成固定膜活性污泥（IFAS）城市废水处理设施中微生物群落转录组表达的影响，该设施中氮的去除主要由 comammox 和 anammox 细菌种群完成。16S rRNA 转录组成表明，与悬浮污泥生物量相比，anammox 细菌和 在 IFAS 生物膜中更活跃。在 IFAS 生物膜中，anammox 细菌在较低的溶解氧浓度下显著增加了 的表达，这种增加与 comammox 细菌的 表达水平高度相关。有趣的是，与溶解氧浓度降低时氨氧化相关的基因相比，comammox 细菌参与亚硝酸盐氧化的基因显著上调。最终，我们的研究结果表明，comammox 通过氨氧化为 anammox 细菌提供亚硝酸盐，这种协同作用依赖于溶解氧浓度。
