The wastewater treatment plant(WWTP)is an indispensable unit of modern cities,which is important for the access to safe water and the sustainable development of cities.Biological treatment process is the most widely used technique in municipal wastewater treatment,in which microbial communities play key roles in pollutant removal.Thus,understanding diversity and composition of microbial communities in WWTPs is key to the understanding of the biological wastewater treatment processes.Also,clarification of mi...