The objective of the present study was to investigate the feasibility of using a gliding arc (GA) discharge to inactivate microorganisms in water. Microbubble generators were utilized to uniformly disperse gas bubbles that contain H2O2 in water. In addition, the residual effect of H2O2 in plasma-treated water was assessed by continuous quantitative measurement of microbiological colony forming units (cfu) in water after the completion of GA discharge. Application of the GA plasma discharge to water decreased pH from 6.15 to 3.55 after 25-min treatment, and the lowered pH was maintained for 4 h after treatment ceased. The present study showed a total 6-log reduction in the cfu counts of Escherichia Coil with plasma treatment of 25 min duration: 4-log reduction from 10(6) to 10(2) during treatment and an additional 2-log reduction from 10(2) to 10(0) during the 2 h after treatment. The use of microbubble generators significantly enhanced the benefit of H2O2 in acidic water, increasing the bacterial inactivation ability of the plasma treatment with GA discharge. (C) 2013 Elsevier B.V. All rights reserved.