Microbial characteristics of tailwater from rural domestic sewage treatment facilities in subsurface constructed wetlands
Rural domestic sewage was treated by A1/O1/A2/O2 facilities and flowed into the subsurface constructed wetland(abbrevi-ated as constructed wetland).To reveal its biodegradation characteristics,the microbial characteristics of constructed wetland were an-alyzed through urease activity and microbial amplicon sequencing.The results showed that the urease activity at the inlet of the con-structed wetland was higher than that at the outlet.The urease activity at the outlet was significantly positively correlated with the total nitrogen removal rate.The higher the urease activity at the outlet,the better the total nitrogen removal effect;microbial amplicon se-quencing showed that the dominant bacterial phyla in constructed wetland were Proteobacteria,Bacteroidetes,and Firmicutes.The rel-ative abundance of Proteobacteria and Bacteroidetes decreased by 8.41 percentage points and 12.14 percentage points respectively from the inlet to the outlet,while Firmicutes increased by 12.91 percentage points;the content of denitrifying bacteria in the inlet and outlet of the constructed wetland was relatively high,with relative abundances of 20.51%and 14.18%,respectively.Among them,the bacteria with heterotrophic nitrification and denitrification functions were also relatively abundant,with 8.54%and 7.44%,respectively.