Inhibition of Escherichia coli by hydrodynamic cavitation discharge plasma for water disinfection suggests the influence of both reactive oxygen species and electroporation

Water contamination by microbial pathogens is a major health issue, yet the efficiency of traditional water disinfection methods is limited. Disinfection is classically attributed to reactive oxygen species, but here we hypothesize that membrane electroporation could also contribute. We developed a hydrodynamic cavitation discharge plasma fore water treatment setup, then evaluated its performance using Escherichia coli. We studied the effect of pulse frequency, pulse duration, and total treatment time. Results show 95% disinfection rate at a pulse frequency of 6 kHz and a duration of 7 μs. The efficiency increased with the total treatment time, suggesting the involvement of reactive oxygen species. A theoretical calculation suggests that the disinfection mechanism involves electroporation of cell membranes, in addition to the role of reactive oxygen species.