Characterization of a Plasma Source for Water Treatment Using Electrical, Optical, and Chemical Diagnostics

Hospital and urban wastewaters constitute major reservoirs of multidrug-resistant bacteria (MRB), antibiotic resistance genes (ARGs), and persistent pharmaceutical contaminants, which are only partially removed by conventional treatment plants. As a result, these pollutants are frequently detected in treated effluents destined for environmental discharge or reuse, raising serious public health concerns-especially for agricultural irrigation. This study explores a novel immersed dielectric barrier discharge (DBD) plasma source engineered for point-of-use decontamination of wastewater at emission sites. The plasma device was thoroughly characterized by electrical, optical, and chemical diagnostics to elucidate its operating regimes and capacity to generate reactive oxygen and nitrogen species (RONS) at the plasma-liquid interface. Findings demonstrate that the composition of the carrier gas critically shapes the production and transfer of short-and long-lived oxidants into the liquid phase. These results provide quantitative insights that support the ongoing optimization of plasma-based advanced oxidation systems for decentralized water treatment. They further illustrate how the careful control of plasma and gas composition can enhance the formation and transfer of oxidants, contributing to the broader field of plasma-liquid applications for the mitigation of emerging contaminants.