Bacteria Inactivation Using Low Power Pulsed Gliding Arc Discharges with Water Spray

Low temperature atmospheric pressure plasma (produced by a 250 mW pulsed gliding arc discharge) with water spray was utilized to inactivate bacteria colonies of Escherichia coli grown on the surface of an agar substrate. The pH, solution conductivity, H2O2, and nitrate concentrations were determined for air and argon carrier gases and different water flow rates. Control experiments conducted by spraying solutions of H2O2 in the absence of the discharge demonstrated that this chemical and its delivery by spraying account for approximately two to three orders of magnitude (depending upon bacterial loading) of the bacterial colony decontamination process for Discharge Arc both carrier gases when bacteria are allowed to grow on the agar plate to form a biofilm. Reactive species or other factors arising from the gas flow from the plasma with the water spray caused bacteria inactivation of one to two orders of magnitude beyond those of spraying H2O2 alone.