Assessing antibiotics biotransformation kinetics and microbial communities in an anaerobic structured fixed-bed biofilm reactor applied to wastewater treatment

The global scientific literature has revealed the excessive use of antibiotics in human and veterinary treatments and the spread of antibiotic-resistant bacteria, necessitating better wastewater treatment methods. This study examined the Anaerobic Structured Fixed-Bed Biofilm Reactor (AnFBR) and its kinetics for the removal of 9 antibiotics (inclunding 4 fluoroquinolones, 4 sulfonamides, and 1 diaminopyrimidine) from lab-made hospital wastewater. Furthermore, the study evaluated the microbial communities present in the reactor bed biofilm. PF-AnFBR demonstrated the highest removal efficiencies for all sulfonamide antibiotics, as well as two fluoroquinolone antibiotics and trimethoprim. The analysis of the microbial community revealed a diverse population in the reactor, with key bacteria genera such as Aeromonas and Pseudomonas playing significant roles in the biodegradation of antibiotics. The presence of the archaeon Methanothrix was crucial for maintaining the stability of the reactor and improving biodegradation processes. This study emphasizes the need to optimize reactor configurations and hydraulic retention times for the efficient removal of antibiotics from wastewater.