Degradation of Vibrio cholerae from drinking water by the underwater capillary discharge

Abstract

Underwater plasma discharge is considered a nontoxic and effectual purification approach to control waterborne bacterial pathogens. In the present study, Vibrio cholerae contaminated drinking water was sterilized by using underwater capillary discharge generation via high voltage, oxygen ( O 2 {{\rm{O}}}_{2} ) injection, and hydrogen peroxide ( H 2 O 2 {{\rm{H}}}_{2}{{\rm{O}}}_{2} ) addition. The effects of oxidant species generated by plasma discharge on V. cholerae disinfection have been studied and reported. The electrical and optical analysis of capillary discharge revealed the generation of reactive oxygen species ( OH . {{\rm{OH}}}^{.} , H and O), which are highly useful for bacterial disinfection along with enhanced power and energy of discharge pulses. Complete elimination of V. cholerae (0 CFUs (colony forming units)) from the water after O 2 {{\rm{O}}}_{2} injected and H 2 O 2 {{\rm{H}}}_{2}{{\rm{O}}}_{2} added plasma discharge was achieved, and 100% inactivation of V. cholera from drinking water was proven. The retardant effect of the initial V. cholerae colonies with time variation was reported through optical density (OD600 nm) measurements. The time course study of bactericidal activity of plasma treatment on V. cholerae, observed every 12 h up to 36 h, revealed a high retardant effect on V. cholerae CFUs. Underwater capillary discharge is an efficient approach for the inactivation of V. cholerae from drinking water.