The low temperature of sewage in north China results in low performance of biological treatment at municipal wastewater treatment plants (MWTPs), especially in biological nitrogen removal. A modified two-stage A/O process with an embedded biofilm was proposed to enhance nitrogen removal. The operation performance of a pilot test was compared with an A²/O and SBR process at existing MWTPs to investigate the resistance to low temperature. The microbial communities for the three processes were compared based on the metagenomics results of 16sDNA high-throughput sequencing from activated sludge. The modified A/O resulted in a higher average removal of COD (90.12%) than A²/O (85.23%) and SBR (83.03%), especially of small-molecule organic compounds (< 500 Da) and macromolecular refractory organics (> 5 k Da); the TN removal rate of A2/O, SBR and the modified A/O was also increased from 74.47%, 70.63% and 78.46%, respectively. High-throughput sequencing revealed increased microbial diversity and an abundance of denitrifying functional bacteria was observed in the modified A/O process at low temperatures. The abundance of nitrite oxidation bacteria (NOB) including Nitrosomonas and Nitrospira, the amount was 1.76% and 2.34% in modified A/O, respectively, whereas NOB only accounted for 1.82% in A²/O and 1.35% in SBR.

华北地区污水温度低，导致城市污水处理厂（MWTPs）的生物处理性能低下，尤其是生物脱氮。提出了一种改进的带有嵌入生物膜的两阶段 A/O 工艺来增强脱氮能力。将中试的运行性能与现有 MWTP的 A ² /O 和 SBR 工艺进行比较，以研究其耐低温性。基于来自活性污泥的 16sDNA 高通量测序的宏基因组学结果比较了三个过程的微生物群落。改良的 A/O 导致 COD 平均去除率 (90.12%) 高于 A ²/O (85.23%) 和 SBR (83.03%)，尤其是小分子有机化合物 (< 500 Da) 和大分子难熔有机物 (> 5 k Da)；A2/O、SBR和改性A/O的TN去除率也分别从74.47%、70.63%和78.46%提高。高通量测序显示微生物多样性增加，并且在低温改良 A/O 工艺中观察到大量反硝化功能细菌。亚硝酸盐氧化菌(NOB)的丰度包括Nitrosomonas和Nitrospira，在改性A/O中的含量分别为1.76%和2.34%，而NOB在A ² /O中仅占1.82%，在SBR中仅占1.35%。