Ozone is a well-known disinfecting agent that is used as an alternative for chlorine in many applications, including water decontamination. However, the utility of ozone in water decontamination is limited by high electrical power consumption and expensive, bulky equipment associated with ozone generation. This study investigates the effectiveness of a lightweight, compact surface dielectric barrier discharge (SDBD) reactor as an ozone generator to inactivate Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) in an open water system. Experimental details are provided for ozone generation technique, mixing method, ozone concentrations in air and water, and input energy required to produce adequate ozone concentrations for bacterial inactivation in a contaminated, open water system. Specifically, an active plasma module (APM) reactor system of size 48 cubic centimeters, weighing 55 grams, with a maximum ozone yield of 68.6 g/KWh was used in atmospheric conditions as the source of ozone along with an air pump and a diffusion stone for mixing the ozone in water. Over 4-log reduction in P. aeruginosa concentration was achieved in 4 minutes with 0.1 mg/L ozone concentration in an open water system using 8.8 ± 1.48 J input energy. Also, over 5-log reduction in MRSA concentration was achieved in 2 minutes with 0.04 mg/L ozone concentration in an open water system using 4.4 ± 0.74 J input energy.

This study introduces spatially targeted decontamination using a synergistic combination of dielectric barrier discharge (DBD) flow actuation and ozone generation. Here, we relate the spatial distribution of local microbial decontaminations in an enclosure to that of local ozone concentrations caused by DBD ozone generation and flow actuation using two reactors with contrasting flow actuation, the Fan and Comb reactors, run at equal power of 1 ± 0.03 W for 3.5 min. Deviations in ozone concentrations and reductions of Escherichia coli on contaminated coupons over two planes were used to quantify the utilization capacity of the generated ozone to simultaneously disinfect regions of a surface placed in the planes. Results show that uniform ozone consumption by a contaminated target, i.e., targeted decontamination, lowers ozone requirements, exposure times, and reactor energy consumption for its disinfection. Furthermore, a significant positive correlation was found between local decontamination and ozone concentrations with Pearson’s correlation, ρ (34) = 0.64; p < 0.001. Simulated ozone distribution using an experiment integrated simulation method, governed by DBD reactor geometry induced flow actuation and ozone reaction rates, is also presented for predicting DBD actuated spatial decontamination distribution. Our study shows an innovative approach of applying DBD plasma reactors for decontamination using flow actuation and ozone generation to achieve targeted killing with maximized ozone utilization lowering overall ozone dosage requirements, energy requirements, and exposure times.

Dielectric Barrier Discharge (DBD) based ozone therapy is an attractive non-thermal, additive-free and environment-friendly alternative to traditional food processing technologies. Its practical application is dependent on economical ozone generation and optimum ozone dosage. This study investigates the one-time and periodic application of a compact (48 cu. cm), lightweight (55 g), low power, low temperature, DBD ozone generator for treatment of spoilage inocula prepared from combinations of spoiled green beans, grape tomatoes, lettuce and strawberries. A one-time exposure of 126–136 ppm of average ozone concentration produced by the DBD generator over 3 min and 15 min resulted in at least 1 and 4 log reduction, respectively, in microbial colonies present in the spoilage inocula. Daily exposure of 128.7 ppm average ozone concentration over 3 min under similar conditions showed that inhibition through periodic exposure can successfully inhibit the growth of both bacteria and mold species with at least 5 log reduction of microbial colonies. Visual inspection of whole fruits and vegetables with similar 3-min daily exposure showed the potential of ozone therapy to at least double the shelf-life of food products. For the daily exposures, energy required by the DBD ozone generator was calculated as 0.39 $$\pm $$ ± 0.06 kJ/day.

This paper presents a proof-of-concept study establishing effectiveness of the Active Plasma Sterilizer (APS) for decontamination in planetary protection. The APS uses Compact Portable Plasma Reactors (CPPRs) to produce surface dielectric barrier discharge, a type of cold plasma, using ambient air to generate and distribute reactive species like ozone used for decontamination. Decontamination tests were performed with pathogenic bacteria (Escherichia coli and Bacillus subtilis) on materials (Aluminum, Polycarbonate, Kevlar and Orthofabric) relevant to space missions. Results show that the APS can achieve 4 to 5 log reductions of pathogenic bacteria on four selected materials, simultaneously at 11 points within 30 min, using power of 13.2 ± 2.22 W. Spatial decontamination data shows the APS can uniformly sterilize several areas of a contaminated surface within 30 min. Ozone penetration through Kevlar and Orthofabric layers was achieved using the CPPR with no external agent assisting penetration. Preliminary material compatibility tests with SEM analysis of the APS exposed materials showed no significant material damage. Thus, this study shows the potential of the APS as a light-weight sustainable decontamination technology for planetary protection with advantages of uniform spatial decontamination, low processing temperatures, low exposure times, material compatibility and the ability to disinfect porous surfaces.

This paper introduces a novel fan-shaped plasma reactor, which employs vortex-induced airflow by atmospheric dielectric barrier discharge to enhance mixing and the resulting distribution of the neighboring species of generated ozone. Through stereoscopic PIV and smoke flow visualizations it was demonstrated that mechanisms of suction, vortex creation and ejection of the fluid combine to form a vertical turbulent flow that yields a more controlled and uniform ozone distribution. The performance of the fan reactor was compared to that of a conventional comb reactor for three cross-sectional planes of a space volume simulating the decontamination environment. Results show that with the fan reactor, ozone starts spreading from the center of the plane, which makes the reactor itself responsible for most of the mixing and ozone’s distribution pattern; whereas in the case of the comb reactor, mixing seems to be mostly dependent on the interaction between the reactor’s characteristic flow and the boundaries of the space volume.