Inactivation of Aquatic Microorganisms by Low-Frequency AC Discharges

Hybrid gas-liquid electrical discharge has been investigated in recent years as an innovative technology for contaminated water treatment. A high-voltage pulsed-power supply is commonly needed for the generation of electrical discharges. This paper aims, in lieu of cost effectiveness, to evaluate the degradation efficiency of electrical discharges with an alternating-current (ac) power since it is generally cheaper than a pulsed one. An ac power supply with a fixed voltage of 13 kV and a fixed frequency of 60 Hz is therefore adopted in this paper for the inactivation of aquatic microorganism. The energies required for one log order of reduction of E. coli, S. aureus, and Yeast were 23, 34, and 31 J/ml, respectively. The energy efficiencies achieved with an ac power in this paper are comparable with other studies that achieved with a pulsed-power.