Diversity of Activated Sludge Microbial Community Structure in Different Wastewater Treatment Plants

—The microbial diversity and community structure of activated sludge in the biological treatment units of five municipal WWTPs and two industrial WWTPs were studied. The results showed that industrial WWTPs had the lowest diversity and abundance of activated sludge microbial communities, indicating that industrial wastewater inhibited the growth of microbial communities. In the correlation analysis between environmental factors and microbial diversity indices, pH and COD showed a significant negative correlation with the number of OTUs and microbial diversity. The main dominant microbial genus were Hyphomicrobium , Acinetobacter , Novosphingobium , Acinetobacter , and Meiothermus . Both principal coordinate analysis (PCoA) and phylogenetic analysis showed large differences in the structure of municipal and industrial microbial community structure, indicating the uniqueness of the activated sludge community structure in industrial WWTPs. Gene function predictions indicated that LJ had higher metabolic function associated with inorganic salt and lipid metabolism. Further co-occurrence network analysis showed that many of the key industrial WWTPs belonged in the same module, suggesting that they had strong interspecific interactions but were relatively independent from other microorganisms in the municipal WWTPs. This study broadens our understanding of microbial community differences between municipal WWTPs and industrial WWTPs.