Harnessing reactive species for water disinfection: Efficacy, challenges, and emerging research needs

Despite their widespread use, conventional disinfection technologies, including chlorination, ozonation, and ultraviolet irradiation, are increasingly constrained by bacterial regrowth, resistance, and harmful by-products. Reactive species (RS)-driven processes present a promising alternative, delivering efficient oxidative disinfection through targeted membrane disruption, enzyme oxidation, and nucleic acid damage. This review discusses recent progress in catalytic and energy-assisted generation of reactive oxygen, nitrogen, sulfur, and chlorine species within advanced oxidation systems. Emphasis is placed on key operational parameters and optimization strategies of the RS activation systems, alongside the underlying antibacterial mechanisms that govern bacterial inactivation and suppression of antibiotic resistance genes (ARGs). Key methodological and interpretative limitations within current RS disinfection studies are critically examined. To improve comparability across studies, the review proposes energy-normalized performance metrics and hierarchical endpoint framework that distinguishes culture-based inactivation from higher-tier genetic outcomes such as ARG disruption. The need for multi-method cross-validation in RS attribution is highlighted. A structured matrix-mechanism framework is introduced to guide matrix-informed system selection and sustainable deployment of RS-based disinfection technologies. Finally, recommendations that will promote environmental sustainability and real-world adaptability of emerging RS-based disinfection strategies are outlined.