Responses of flocculent and granular sludge in anaerobic sequencing batch reactors (ASBRs) to azithromycin wastewater and its impact on microbial communities

Abstract

BACKGROUNDAzithromycin (AZM), a 15‐member macrolide antibiotic, has caused widespread pollution in China, where anaerobic digestion is the predominant wastewater treatment technology. However, the type of anaerobic sludge most suitable for treating antibiotic wastewater is unclear. Therefore, this study aimed to determine the response of anaerobic flocculent and granular sludge to AZM wastewater, and, using a high‐throughput sequencing technique, to explain the diverse microbial community structures.RESULTSAnaerobic granular sludge provided better resistance to the decline of chemical oxygen demand (COD) removal caused by AZM and greater biodegradation efficiency than flocculent sludge. Furthermore, there was stronger resistance to AZM‐induced reactive oxygen species in the granular sludge than in the flocculent sludge. The granular sludge exhibited richer microbial communities than the flocculent sludge after AZM exposure to the phylum Proteobacteria and Bacteroidetes.CONCLUSIONAt high AZM concentration, anaerobic granular sludge was superior to flocculent sludge in COD removal and AZM degradation. This is attributed to less cell death and greater microbial diversity and richness in the granular sludge than in the flocculent sludge following exposure to AZM. Proteobacteria and Bacteroidetes contributed to the resistance to AZM in the granular sludge. © 2018 Society of Chemical Industry

Insights into the Fate and Removal of Antibiotics in Engineered Biological Treatment Systems: A Critical Review

“…More recently, application of granular sludge in anaerobic SBR was investigated for treatment of AZI containing wastewater. On the basis of mass balance analysis, biodegradation was found to be the major removal pathway for AZI with an average removal efficiency of 31% …”

“…On the basis of mass balance analysis, biodegradation was found to be the major removal pathway for AZI with an average removal efficiency of 31%. 411 Though granular systems exhibited high resistance to elevated antibiotics concentration without a significant impact on overall organic removal, few studies highlighted the influence of antibiotics on granular biomass properties and structural stability. Decrease in granular size and disintegration of granules was evident due to continuous exposure of antibiotics such as FQs (OFX, NOFX and CIP), TCs (TET), and BLAs (AMPI and CEFX) at higher concentrations.…”