Abstract:The performance and stability of the biological wastewater treatment system are closely related to the microbial community structure and dynamics. An in-depth understanding of the microbial community structure in activated sludge and its influencing factors can contribute to improve pollutants removal in the treatment process. In different sewage wastewater treatment systems, the distribution of bacterial communities mainly consists of Proteobacteria, Campylobacter, Actinomycetes, Pachythromycetes and Bacteroides. Most of the fungi living in activated sludge belong to Ascomycota and a small amount of Basidiomycota. Meanwhile, the most widely distributed bacteriophages and pathogenic viruses in the virus are the major concerns. By analyzing and summarizing relevant literatures, this paper reviews the environmental factors such as influent composition, different treatment processes, parameters (physicochemical parameters and operating parameters), geographical location and climatic conditions on bacteria, fungi, archaea and virus in activated sludge, and introduces the diversity of microbial communities in sewage plants and their responses to environmental factors as comprehensively as possible. At the same time, the future research direction is discussed in order to provide theoretical and application basis for regulation of functional microorganisms in activated sludge.
