TECHNOLOGY FOR WATER DISINFECTION AND PURIFICATION USING THE SYNCHRONOUS ACTION OF A HIGH ELECTRIC FIELD AND NANOSECOND DISCHARGES WITH SUBNANOSECOND PULSE FRONTS IN GAS BUBBLES

Abstract

This paper demonstrates that, in water-disinfection reactors employing nanosecond discharges with subnanosecond fronts in air bubbles, pulse amplitudes of up to 500 kV can be achieved while maintaining atmospheric pressure inside the air bubbles. All other conditions being equal, the specific energy consumption associated with nanosecond pulses having subnanosecond fronts is significantly lower than that of microsecond pulses. The critical electric field strength Ecr (Dreicer critical field) required for an electron to become a runaway electron in an inhomogeneous electric field was calculated for nitrogen and found to be approximately Ecr≈725 (kV/cm). It is shown that that the use of two step-up pulse transformers based on the Tesla configuration enables voltages of up to 500kV to be generated at the secondary winding terminals of the second transformer within less than 100ns(tch2<100 ns), owing to the small number of turns (≤10) in this winding. An electrical circuit diagram and a schematic of a flow-through reactor for a high-voltage installation implementing the proposed water disinfection and purification technology are presented. The proposed reactor design reduces untreated water zones to zero. Such reactors can be connected in parallel or in series, thereby increasing the treatment capacity of the installation. References 14, figures 5.