城市污水处理厂进水氨氧化菌对活性污泥系统的季节性影响

为考察进水氨氧化菌（AOB）对活性污泥系统的季节性影响，对未设置初沉池的西安市第二污水处理厂中进水及活性污泥的氨氧化活性及群落结构进行长期调查分析.结果表明，进水及活性污泥的比氨氧化速率（SAUR）分别为0.48~3.02 mg·（g·h）^-1和0.68~2.25 mg·（g·h）^-1，相关性分析结果显示进水SAUR与次月活性污泥SAUR高度相关（r=0.862，P<0.05），表明进水硝化菌对活性污泥硝化性能有显著影响.根据硝化活性计算的进水AOB对活性污泥的接种强度为0.21~0.92 g·（g·d）^-1，因此，在优化活性污泥模型及污水厂设计时，有必要考虑到进水硝化菌的迁移作用.qPCR结果显示，进水及活性污泥中AOB丰度分别为1.32×10⁸~2.36×10⁹cells·g^-1和1.12×10¹⁰~1.19×10¹⁰ cells·g^-1，而冬季活性污泥中AOB丰度虽有降低，但仍保持在10¹⁰ cells·g^-1，这说明进水硝化菌的迁移能缓解因温度降低而导致的活性污泥硝化菌丰度下降.Illumina MiSeq测序结果表明，进水和活性污泥中具有共同的优势AOB，分为Nitrosomonas sp.Nm58、Nitrosomonas sp.JL21和bacterium CYCU-0253.

Seasonal Effects of Influent Ammonia Oxidizing Bacteria of Municipal Wastewater Treatment Plants on Activated Sludge System

The specific ammonia uptake rates (SAUR) and ammonia oxidizing bacteria (AOB) community of influent sewage and activated sludge in the 2^nd wastewater treatment plant (WWTP) of Xi''an without the primary settling tank were analyzed over multiple years to explore the seasonal effects of the influent AOB on the activated sludge systems. During the experiment, the SAUR of the raw sewage and activated sludge were 0.48-3.02 mg·(g·h)^-1 and 0.68-2.25 mg·(g·h)^-1, respectively. Meanwhile, the correlation analysis indicated that the monthly SAUR of the raw sewage was highly correlated with that of the activated sludge of the following month (r=0.862,P<0.05), which indicated that influent nitrifiers had a significant effect on the nitrification performance of activated sludge. Considering that the estimated AOB seeding intensities based on the ammonia oxidizing activity were 0.21-0.92 g·(g·d)^-1, the nitrifier immigration from the raw sewage should added to the design of WWTP and the activated sludge modeling. Moreover, the qPCR results revealed that the AOB abundance of activated sludge in winter decreased but remained at 10¹⁰ cells·g^-1, indicating that the immigration of influent nitrifiers could partially compensate for the reduction of the AOB abundance in the activated sludge caused by decreasing temperatures. Finally, the Illumina MiSeq sequencing demonstrated that the shared dominant AOB between the raw sewage and activated sludge were Nitrosomonas sp. Nm58, Nitrosomonas sp. JL21, and bacterium CYCU-0253. These findings can provide theoretical support for the design and operation of a WWTP.