Submerged Spark Plasma Discharges for the Removal of Antibiotics, Antibiotic-Resistant Bacteria, and Resistance Genes.

The widespread use of antibiotics in aquaculture and livestock production has contributed to the dissemination of antibiotics, antibiotic-resistant bacteria (ARB), and antibiotic resistance genes (ARGs) in aquatic environments. In this study, submerged spark plasma systems were evaluated for the removal of rifampicin, rifampicin-resistant Escherichia coli O157:H7, and ARG-associated DNA in different water matrices using a 40 mL single-spark reactor and a 1000 mL multiple-spark reactor. The single-spark system achieved 99.43% removal of rifampicin within 8 min and >5-log reduction of E. coli O157:H7 within 10 min in distilled water. The multiple-spark system achieved up to 78.46% rifampicin removal and >5-log bacterial inactivation depending on power input. Plasma treatment also reduced ARG-associated DNA, including up to 4-log reduction in total DNA and rapid degradation of extracellular DNA to below detection limits within 1 min. Rifampicin degradation followed pseudo-first-order kinetics in the single-spark reactor and pseudo-second-order kinetics in the multiple-spark reactor. Saline water conditions significantly reduced antibiotic degradation, bacterial inactivation, and ARG reduction efficiencies. The lowest electrical energy per order (EEO) for E. coli inactivation was 1.2 kWhr/m3 per 1-log reduction at 60 W in the multiple-spark system. Compared to sodium hypochlorite treatment, submerged spark plasma achieved greater rifampicin degradation and faster extracellular DNA reduction without chemical additives. These findings demonstrate the potential of submerged spark plasma as a multifunctional advanced oxidation and disinfection technology for mitigation of AMR-related contaminants in water treatment applications.