Analysis of microbial communities developed on the fouling layers of a membrane-coupled anaerobic bioreactor applied to wastewater treatment

► Chemical cleaning did not completely remove biofouling layers on membranes. ► Chemical cleaning modified the communities of bacteria but not of Archaea. ► Firmicutes were the major Bacteria group found in the biofouling layers. ► All Archaea identified in the biofouling layers were related to methanogens. ► Sphingomonads and methanogenic Archaea were persistent components of biofouling.