Removal of nalidixic acid and its degradation products by an integrated MBR-ozonation system

► Degradation of the antibacterial nalidixic acid was obtained by integrated MBR-ozonation. ► Synergistic effects of chemical oxidation and bioprocesses were exploited. ► Ozonation oxidized target compound into biodegradable products that were then removed by MBR. ► Ozonation caused no relevant drawbacks to biological and filtration processes in the MBR. ► Integrated process was more efficient than sequential configuration.