Currently, little information is available on how the particle size would influence the physicochemical characteristics, nitrogen conversion activity and microbial community in the anammox sludge granules. This study was targeting to answer the question by studying anammox granular sludge with average particle sizes ranging from 0.5 − 1.0, 1.0 − 1.5, 1.5 − 2.0 and > 2.0 mm. Results indicated that the wet density and settling velocity were positively correlated with particle size. However, the volatile suspended sludge/suspended sludge (VSS/SS) ratio and particle integrity coefficient (IC) decreased with an increase in particle size. The granular sludge with a particle size of 1.0 − 1.5 mm had the largest extracellular polymeric substances (EPS) content and protein/polysaccharide (PN/PS) ratio. The removal efficiency of ammonium and nitrite as well as the specific anammox activity (SAA) increased with an increase in particle size. High-throughput sequencing showed that the richness and diversity of the microbial community decreased firstly and then increased with an increase in particle size. The granular sludge with a particle size of 1.0 − 1.5 mm had the lowest diversity, but that of 0.5 − 1.0 mm had the largest biomass and relative abundance values of anammox bacteria. The granular sludge size should be controlled below 1.5 mm to maintain the predominant microorganisms of anammox bacteria, while particle sizes of 1.5 − 2.0 mm should be selected to maintain high nitrogen removal performance.

目前，关于颗粒大小如何影响厌氧氨氧化污泥颗粒中的理化特性，氮转化活性和微生物群落的信息很少。这项研究旨在通过研究平均粒径为0.5-1.0、1.0-1.5、1.5-2.0和> 2.0 mm的厌氧颗粒污泥来回答这个问题。结果表明，湿密度和沉降速度与粒径呈正相关。但是，随着颗粒尺寸的增加，挥发性悬浮污泥/悬浮污泥的比率（VSS / SS）和颗粒完整性系数（IC）降低。粒径为1.0-1.5 mm的颗粒状污泥具有最大的细胞外聚合物（EPS）含量和蛋白质/多糖（PN / PS）比。氨和亚硝酸盐的去除效率以及特定的厌氧氨氧化活性（SAA）随着粒径的增加而增加。高通量测序表明，微生物群落的丰富度和多样性首先随着粒径的增加而减小，然后增加。粒径为1.0-1.5 mm的颗粒污泥的多样性最低，但0.5-1.0 mm的颗粒污泥的最大生物量和厌氧菌的相对丰度值。颗粒污泥的大小应控制在1.5 mm以下，以保持厌氧细菌的主要微生物，而颗粒大小应选择1.5-2.0 mm，以保持较高的脱氮性能。高通量测序表明，微生物群落的丰富度和多样性首先随着粒径的增加而减小，然后增加。粒径为1.0-1.5 mm的颗粒污泥的多样性最低，但0.5-1.0 mm的颗粒污泥的最大生物量和厌氧菌的相对丰度值。颗粒污泥的大小应控制在1.5 mm以下，以保持厌氧细菌的主要微生物，而颗粒大小应选择1.5-2.0 mm，以保持较高的脱氮性能。高通量测序表明，微生物群落的丰富度和多样性首先随着粒径的增加而减小，然后增加。粒径为1.0-1.5 mm的颗粒污泥的多样性最低，但0.5-1.0 mm的颗粒污泥的最大生物量和厌氧菌的相对丰度值。颗粒污泥的大小应控制在1.5 mm以下，以保持厌氧细菌的主要微生物，而颗粒大小应选择1.5-2.0 mm，以保持较高的脱氮性能。0 mm的厌氧菌具有最大的生物量和相对丰度值。颗粒污泥的大小应控制在1.5 mm以下，以保持厌氧细菌的主要微生物，而颗粒大小应选择1.5-2.0 mm，以保持较高的脱氮性能。0 mm的厌氧菌具有最大的生物量和相对丰度值。颗粒污泥的大小应控制在1.5 mm以下，以保持厌氧细菌的主要微生物，而颗粒大小应选择1.5-2.0 mm，以保持较高的脱氮性能。