Evaluation of microbial diversity of activated sludge in a municipal wastewater treatment plant of northern China by high-throughput sequencing technology

Samples collected in summer and winter were analyzed by high-throughput sequencing technology to reveal differences in the microbial community diversity of activated sludge at different temperatures in a municipal wastewater treatment plant of Northern China. A total of 36,438 validated reads were obtained from the samples, and the bacteria belonged to 25 phyla and 139 genera. The Shannon diversity index decreased from 5.367 in summer to 5.168 in winter. During summer, the dominant phylum was Proteobacteria (50.5%), while it was Bacteroidetes during winter (40.5%). At the genus level, Chitinophaga was most abundant during summer (8.7%), while Haliscomenobacter (2.8%) had the greatest abundance in winter. Almost all nitrogen and phosphorus removal-related functional microbes, including Thiobacillus (denitrifying bacteria), Rhodocyclus (phosphorus-accumulating bacteria), and Nitrosomonadaceae (ammonia-oxidizing bacteria), showed significantly higher abundance in summer than winter. Conversely, cryophilic microbial abundance was significantly higher in winter than summer.