A novel integrated microbial fuel cell-membrane bioreactor (MFC-MBR) for controlling the spread of antibiotic and antibiotic resistance genes while simultaneously alleviating membrane fouling

Abstract

The dissemination of antibiotics and antibiotic resistance genes (ARGs) in the environment can potentially pose risks to ecosystems and human health. Herein, a novel microbial fuel cell and membrane bioreactor (MFC-MBR) integrated system characterized by internal reflux of sludge mixtures was proposed to reduce antibiotics, control the spread risk of antibiotic resistance genes (ARGs), and simultaneously alleviate membrane fouling. The bioelectricity production was distinctly promoted with increasing return flow ratios under sulfamethoxazole (SMX) addition. Besides, reactors characterized by higher return flow ratios achieved a relatively elevated degradation rate of SMX, attributed to the enhanced microbial activities through electrical stimulation. Importantly, the absolute abundance of intI1, sul1 and sul3 significantly decreased in the effluent of reactors characterized by higher return flow ratios. The value of zeta potential and particle size of sludge flocs subsequently increased and the content of membrane foulants dropped with the increasing return flow ratios. Moreover, MFC-MBRs characterized by higher return flow ratios were enriched in antibiotic degrading bacteria (Firmicutes, Thauera) and electrochemically active bacteria (Proteobacteria, Bacteroidota). Therefore, this study provided a theoretical basis for reducing the spread of antibiotics and ARGs while simultaneously alleviating fouling, achieving the best of both worlds, through the novel MFC-MBR integrated system.