College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China.
College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China.
J Environ Manage. 2024 Mar;355:120194. doi: 10.1016/j.jenvman.2024.120194. Epub 2024 Mar 1.
Strengthening the activity competitiveness of anaerobic ammonium oxidation (anammox) bacteria (AnAOB) under low nitrogen conditions is indispensable for mainstream anammox application. This study demonstrates that sponge iron addition (42.8 g/L) effectively increased apparent AnAOB activity and extracellular polymeric substance (EPS) production of low load anammox biofilms cultivated under low (influent of 60 mg N/L) and even ultra-low (influent of 10 mg N/L) nitrogen conditions. In-situ batch tests showed that after sponge iron addition the specific AnAOB activity in the low and ultra-low nitrogen systems further increased to 1.18 and 0.47 mmol/g VSS/h, respectively, with an apparent growth rate for AnAOB of 0.011 ± 0.001 d and 0.004 ± 0.001 d, respectively. The averaged EPS concentration of anammox biofilm in both low (from 35.84 to 71.05 mg/g VSS) and ultra-low (from 44.14 to 57.59 mg/g VSS) nitrogen systems increased significantly, while a higher EPS protein/polysaccharide ratio, which was positively correlated with AnAOB activity, was observed in the low nitrogen system (3.54 ± 0.34) than that in the ultra-low nitrogen system (1.82 ± 0.10). In addition, Candidatus Brocadia was detected as dominant AnAOB in the anammox biofilm under the low (12.2 %) and ultra-low (24.7 %) nitrogen condition. Notably, the genus Streptomyces (26.3 %), capable for funge-like codenitrification, increased unexpectedly in the low nitrogen system, but not affecting the nitrogen removal performance. Therefore, using sponge iron to strengthen AnAOB activity under low nitrogen conditions is feasible, providing support for mainstream anammox applications.
强化低氮条件下厌氧氨氧化（Anammox）细菌的活性竞争力对于主流 Anammox 应用至关重要。本研究表明，添加海绵铁（42.8 g/L）可有效提高低负荷 Anammox 生物膜在低氮（进水氮浓度 60 mg/L）甚至超低氮（进水氮浓度 10 mg/L）条件下的表观 AnAOB 活性和胞外聚合物（EPS）的产生。原位间歇试验表明，添加海绵铁后，低氮和超低氮系统中的特定 AnAOB 活性进一步分别提高到 1.18 和 0.47 mmol/g VSS/h，AnAOB 的表观生长速率分别为 0.011±0.001 d 和 0.004±0.001 d。在低氮（从 35.84 到 71.05 mg/g VSS）和超低氮（从 44.14 到 57.59 mg/g VSS）系统中，Anammox 生物膜的平均 EPS 浓度均显著增加，而在低氮系统中观察到更高的 EPS 蛋白/多糖比（与 AnAOB 活性呈正相关）（3.54±0.34），高于超低氮系统（1.82±0.10）。此外，在低氮（12.2%）和超低氮（24.7%）条件下，在 Anammox 生物膜中检测到优势 Ana-mox 菌为 Candidatus Brocadia。值得注意的是，在低氮系统中，一种能够进行类固氮功能的 Streptomyces 属（26.3%）出乎意料地增加，但不影响氮去除性能。因此，在低氮条件下使用海绵铁来强化 AnAOB 活性是可行的，为主流 Anammox 的应用提供了支持。
