Low-energy ORR/EO-Cl system with commercial electrodes for real medical wastewater disinfection achieves efficient inactivation, Chloroxy-anion suppression, and multi-level bacterial damage

An ORR/EO-Cl system using commercial electrodes achieves efficient disinfection at 5 mA/cm 2 . • Cathodic H 2 O 2 consumes anodic free chlorine to generate 1 O 2 as the dominant bactericide. • The system suppresses chlorate and chlorite formation in real medical wastewater. • Multi-level oxidative damage to membranes, DNA, proteins and lipids causes irreversible inactivation. Electrochemical disinfection of chloride-rich medical wastewater faces an inherent trade-off: killing pathogens efficiently while avoiding toxic chlorate and chlorite formation. Here we show that coupling oxygen reduction at a commercial carbon felt cathode with chlorine evolution at a DSA@Ru/Ir anode breaks this trade-off. At 5 mA/cm 2 , cathodic H 2 O 2 rapidly consumes anodic free chlorine, generating singlet oxygen ( 1 O 2 ) as the dominant bactericidal species while suppressing chlorate and chlorite. In real hospital wastewater, chlorate drops from 0.66 to 0.39 mg/L, and the system inactivates 10 7  CFU/mL Escherichia coli in 5 min and Staphylococcus aureus in 10 min-using, the energy consumption was 0.1169 kWh/m 3 and 0.2338 kWh /m 3 , respectively. Quenching, flow cytometry, DNA electrophoresis, protein carbonylation and lipid peroxidation collectively confirm that 1 O 2 -driven oxidative stress causes irreversible membrane, DNA, protein and lipid damage. This work offers a low-energy, commercially viable strategy for electrochemical disinfection of real medical wastewater with intrinsic byproduct suppression. Download: Download high-res image (85KB) Download: Download full-size image