Biofilm aging in full-scale aerobic bioreactors from perspectives of metabolic activity and microbial community

The objective of this study was to establish a quantitative response to biofilm aging from perspectives of metabolic activity and microbial community applied in distinct wastewater. Biofihns developed on soft, integrated and suspended biocarriers in three full-scale aerobic bioreactors under stable operations from municipal and industrial wastewater treatment plants, were tracked for more than 11 weeks for biofilm aging study. Results showed the first evidence of biofilm aging in full-scale aerobic bioreactors by adenylate energy charge (AEC) that biofilm needed to be reactivated when AEC was less than 0.6. Biofilm aged more easily on soft and integrated biocarriers and high salinity, high organic contents and high suspended sludge concentration accelerated the aging process of biofilm. Caldilinea and Acinetobacter predominated in aging biofilm on suspended biocarriers. This study offered a novel evaluation methodology of biofilm aging and was believed to provide important reference for biofilm regulation in biofilm-based wastewater treatment process.