Power Modulator for High-Yield Production of Plasma-Activated Water

Water can be activated by applying plasma to water, for instance, by creating plasma inside (bubbles in) the water, or along a water surface. Plasma-activated water (PAW) typically contains hydrogen peroxide, nitrates, nitrites, and peroxynitrite, and typically has a pH ranging from 2 to 4. The components of PAW and the low pH have proven synergistic antimicrobial effects against bacteria, biofilms, yeasts, and other microorganisms. This paper describes a power modulator and a plasma reactor system for high-yield production of PAW at high production rate. A compact and solid-state dual resonant system has been realized and successfully demonstrated for industrial PAW production. The system generates up to 80-kV (theoretical 120 kV is possible) dual-resonant high-voltage pulses with an oscillation frequency up to 2 MHz, pulse repetition rate > 20 kHz, and an average power of 800-W continuous. In addition to the power modulator, the PAW production system consists of a transient arc plasma reactor and a loop system. Depending on the application, the system is able to activate 10–100 L/h. The disinfecting properties of the PAW production system have been verified by experiments on the reduction of Staphylococcus Epidermidis. Directly after its production, the log reduction of S. Epidermidis can be as high as >8 log. During a period of at least 40 min after its production, the PAW has “mild” disinfecting properties, being able to deactivate S. Epidermidis by 3–4.1 log.