Implementation of a Hyperbolic Vortex Plasma Reactor for the Removal of Micropollutants in Water

The presence of micropollutants in water is an increasingly pressing environmental concern. While some micropollutants are readily biodegradable, others, such as per- and polyfluoroalkyl substances (PFAS), are extremely persistent and resistant to conventional water treatment technologies. Plasma-based treatment has been investigated for water and wastewater decontamination for decades, with recent studies demonstrating its high efficacy in degrading both short- and long-chain PFAS. Here, plasma-based waste treatment is combined with a free surface hyperbolic water vortex, which has an oxygen volumetric mass transfer coefficient exceeding that of similar systems. Various types of plasma discharges can be employed for such applications, each requiring specific power supply configurations and operational strategies. The use of pulsed signals, in particular, presents unique engineering challenges. This study explores the generation and characterization of six different plasma discharge types within a Hyperbolic Vortex Plasma Reactor: pulsed monopolar (negative and positive), pulsed bipolar "flashover," AC and DC arc, and glow discharge. The pulse characteristics of monopolar and bipolar pulsed discharges were analyzed, and their efficiency in PFAS degradation was evaluated. Among the tested configurations, the bipolar flashover discharge exhibited the highest degradation efficiency in a Hyperbolic Vortex Plasma Reactor. However, its practical implementation poses significant engineering challenges, making its utilization challenging on a larger scale.