Plasma-pulse water treatment using a high-voltage underwater spark discharge is a reagent-free approach with potential for simultaneous disinfection and physicochemical modification of water. In this study, a laboratory-scale recirculating reactor (Vtot = 10 L) equipped with a storage capacitor of C = 0.25 μF was operated at U = 15–30 kV and a pulse repetition frequency of about 1.8 Hz to evaluate disinfection performance and system-level energy characteristics for two water matrices, surface wastewater and tap water. The corresponding calculated capacitor-stored energy ranged from 28.1 to 112.5 J per pulse. Microbiological and physicochemical measurements were performed in triplicate. At U = 30 kV, the total microbial count in wastewater decreased from approximately 1 × 105 CFU/mL to below the method detection limit (LOD = 1 CFU/mL) within 2–3 min. For the 2 min/10 L operating mode, the system-level specific energy input was estimated at 6.7 kWh/m3. During the initial treatment period, temperature-compensated conductivity (σ25) decreased by 3–8%, depending on the water matrix, and then increased with prolonged treatment. These results show that the tested reactor can provide rapid reagent-free reduction in culturable microflora under the studied conditions. However, plasma-pulse treatment should be regarded primarily as an advanced treatment, polishing, or pre-treatment option for complex water matrices rather than as a universal replacement for conventional large-volume disinfection technologies.
Shaimerdenova et al. (Sat,) studied this question.