Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
J Environ Manage. 2022 Feb 15;304:114329. doi: 10.1016/j.jenvman.2021.114329. Epub 2021 Dec 20.
Constructing a stable and efficient anammox-driven constructed wetlands (CWs) system for efficiently treating high-nitrogen wastewater with low C/N remains a challenge, due to slow growth rate and high sensitivity of anammox bacteria to changing environmental conditions. Notably, sensitive anammox bacteria is still affected by the physicochemical properties of wetland substrates and their effects are still unknown. Therefore, three single-substrate (gravel, zeolite, and oyster shell) CWs were constructed with the goal of enhancing total nitrogen (TN) removal by anammox-driven/dominant process and determining the effect of substrate on anammox process. The gravel, zeolite and oyster shell systems achieved desired TN removal rates of 20.50, 14.25 and 22.15 g·(m·d) when influent TN load was 32.57 g·(m·d) without carbon source and costly aeration, respectively. Oyster shell system exhibited the highest removal ability and better capacity for resistance to influent nitrogen load, followed by gravel and zeolite systems (p < 0.05). Integrated analyses indicated anammox-driven/dominant process was the foremost reason accounted for the enhanced nitrogen treatment performance in all systems. The abundance of anammox gene was higher than the total abundance of denitrifying genes in the three CWs when influent TN load reached 14.85 g·(m·d). Path analysis further demonstrated anammox process was the foremost nitrogen removal pathway. [anammox] had a highest positive direct contribution (97.3%) on TN transformation rate in gravel system; [anammox/(napA+narG+nirK+nirS+nosZ)] showed highest positive direct contribution (92.4% and 97.4%) on that in zeolite and oyster shell systems, respectively. Substrate configurations significantly affected nitrogen transformation pathway and microbial communities, particularly those of anammox bacteria. Anammox genera of Candidatus Brocadia (primary anammox genera) and Candidatus Kuenenia exhibited different evolutions among the three CWs. Machine learning of Least absolute shrinkage and selection operator (LASSO) analyses showed pH, Ca, Mg, EC, and K were the key physicochemical properties of wetland substrates affecting anammox gene and anammox genera. In conclusion, Oyster shell was the optimal substrate for anammox bacteria growth.
构建稳定且高效的以厌氧氨氧化（Anammox）为主导作用的人工湿地（CWs）系统以高效处理低 C/N 比的高浓度含氮废水仍然具有挑战性，这是由于 Anammox 细菌的生长缓慢且对环境条件的变化非常敏感。值得注意的是，敏感的 Anammox 细菌仍然受到湿地基质理化性质的影响，但它们的作用尚不清楚。因此，本研究构建了三种单基质（砾石、沸石和牡蛎壳）CWs，旨在通过以 Anammox 为主导的过程提高总氮（TN）去除率，并确定基质对 Anammox 过程的影响。当进水 TN 负荷为 32.57 g·(m·d)，无需外加碳源和曝气时，砾石、沸石和牡蛎壳系统的 TN 去除率分别达到了 20.50、14.25 和 22.15 g·(m·d)。牡蛎壳系统表现出最高的去除能力和更好的抗进水氮负荷能力，其次是砾石和沸石系统（p < 0.05）。综合分析表明，以 Anammox 为主导的过程是所有系统中增强氮处理性能的首要原因。当进水 TN 负荷达到 14.85 g·(m·d)时，在三个 CWs 中，Anammox 基因的丰度均高于反硝化基因的总丰度。路径分析进一步表明，Anammox 过程是首要的脱氮途径。在砾石系统中，[Anammox]对 TN 转化速率的直接正向贡献最高（97.3%）；在沸石和牡蛎壳系统中，[Anammox/(napA+narG+nirK+nirS+nosZ)]对 TN 转化速率的直接正向贡献最高（分别为 92.4%和 97.4%）。基质构型显著影响氮转化途径和微生物群落，尤其是 Anammox 细菌。三种 CWs 中的候选布鲁卡氏菌（主要的 Anammox 菌属）和候选库恩氏菌的 Anammox 属的演替不同。最小绝对收缩和选择算子（LASSO）分析的机器学习显示，pH、Ca、Mg、EC 和 K 是影响 Anammox 基因和 Anammox 属的湿地基质关键理化性质。总之，牡蛎壳是 Anammox 细菌生长的最佳基质。
