[Microbial Community Structure of Activated Sludge and its Response to Environmental Factors]

By mining and analyzing the published 16S rRNA amplification data of activated-sludge from 32 sewage and waste-water treatment facilities, at home and abroad, this study examines the microbial structure of sludge and its response to inflow water quality, temperature, and treatment type. Activated sludge generally shows high species diversity and community richness. Many activated sludge samples contain different microbial community structures. In these samples, the dominant bacteria included Thauera, Nitrospira, Comamonas, Dechloromonas, Rhodoferax, Aquihabitans, and Acidovorax. Temperature was negatively correlated with several key denitrifying microorganisms, such as Nitrospira, Aquihabitans, Terrimonas, and Dechloromona. When temperatures were lower than 15℃, the corresponding removal rates of TN and NH₄⁺-N in the 32 sewage treatment plants only reached 49.67% and 63.19%, respectively. With higher BOD₅/COD values, these sewage treatment systems exhibited improved biodegradability performances. With higher relative abundances of advantageous functional bacteria, such as Zoogloea, Arcobacter, Acidovorax, and Acinetobacter, pollutant-removal rates would increase accordingly. As for domestic-sewage treatments, the performance of the A²O process is superior to that of the OD, CAS, and CMAS processes. Additionally, the relative abundances of multiple functional dominant bacteria, including Comamonas, Rhodoferax, Nitrospira, and Novosphingobium, were significantly higher in sludge treated with the A²O process than in sludge treated with the other three processes.