Green electrical disinfection of water

Safe and energy-efficient alternatives to chemical disinfection are urgently needed to address the environmental and health risks associated with chlorination and its by-products. This study demonstrates the effective inactivation of pathogenic microorganisms in drinking water and wastewater using strong electric fields and microsecond pulsed discharges. A 50 kV pulse system with an asymmetrical pin-to-plane reactor was developed, incorporating a mobile fluoroplastic nozzle on the energized electrode to expand the ionization and discharge zone. Experiments operated in a soft spark-discharge mode (~ 20 kV, 1 µF). Substantial microbial reductions were achieved: in wastewater, total coliforms decreased from 3.7 × 107 to 7.2 × 104 CFU per 100 mL and fecal coliforms from 2.6 × 107 to 1.53 × 105 CFU per 100 mL; in drinking water, Escherichia coli was fully eliminated and total microbial load declined from 146 to 15 CFU mL−1. These outcomes correspond to > 2 log10 reduction in wastewater and complete pathogen removal in drinking water. Equivalent-circuit analysis revealed higher per-pulse energy transfer in wastewater (≈ 1.88 J) than in drinking water (≈ 2.10 J), attributed to differences in electrical resistance and capacitance. Microbial inactivation arises from synergistic physical, chemical, and mechanical processes generated during pulsed discharge. The results highlight high-voltage pulsed discharge as a promising, chemical-free, and environmentally responsible alternative to chlorination for water treatment.