• water disinfection;
  • nonthermal plasma;
  • pulsed-power technology;
  • E. coli

An above water-pulsed nonthermal plasma technique for water disinfection is reported. Experiments are performed with a 2.5 L plasma reactor and Escherichia coli. When its initial number density is less than 106 cfu/mL, up to six orders reduction can be achieved within 0.5–2.5 min and at a plasma energy density of less than 2 J/mL. The disinfection performance is always effective by controlling water conductivity of below 1.5 mS/cm, which significantly affects plasma generation. Aqueous hydrogen peroxide, ozone, and nitric acid are continuously accumulated inside the reactor by the processing. Plasma generated UV radiation plays an important role in the cell inactivation. Inactivated cell morphology almost remains the same shape, their intracellular protein like green fluorescent protein, however, is destructed according to fluorescence observation. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1458–1467, 2013