Electrochemical abatement of cefazolin: Towards a viable treatment for antibiotic-containing urine

The release in the environment of antibiotics develop microbial resistance. In this work we investigated the feasibility of the electrochemical degradation in synthetic urine of cefazolin (CFZ), an antibiotic used for the treatment of antibiotic-resistant infections, which could be carried out in hospital wards on source-separated urine. CFZ is primarily excreted in urine without modifications. The removal of CFZ from human wastes would contribute to slow down the diffusion of CFZ-resistant bacterial strains more efficiently, compared to the treatment of much larger volumes of wastewater. CFZ can be electrochemically degraded using relatively low current density (≥0.5 mA cm−2) and without important generation of toxic by-products such as chlorate (<100 μg L−1). Oxidation of the S atoms of CFZ constitutes its main electrodegradation pathway, while the electrochemical generation of H2O2 accounts for most of the bacterial toxicity observed in electrodegraded mixtures. The treatment costs are not an issue because of the relatively low electricity consumption required for CFZ degradation (EEO at 0.5 mA cm−2 current density was always < 1 kWh m−3), while the most challenging endeavours could be the manufacturing of a sufficiently compact apparatus and possibly its management in hospital wards.