Efficient and sustained disinfection via peroxymonosulfate activation with minimal bromide: From laboratory to pilot...

Biosafety in water infrastructure remains an underexplored area in disinfection research. This study introduces a novel peroxymonosulfate (PMS)-based disinfection technique with low bromide (Br^-) input, achieving enhanced and sustained antimicrobial performance. Inactivation kinetics were characterized using mathematical models, revealing an initial lag phase followed by a log-linear profile. The shoulder length (SL) decreased, while the inactivation rate constant (k_lin) increased with higher PMS and Br^- concentrations. The system achieved complete inactivation of highly resistant Aspergillus spores within 30 min at 2 mM PMS and 40 to 80 μM Br^-, whereas Escherichia coli required <3 min. Water matrix factors, including pH, humic acid, ammonia, chloride, and alkalinity, affected disinfection kinetics to varying degrees. Free bromine species (FBS) were identified as the dominant disinfectants, while free radicals played a negligible role. FBS formation kinetic followed a first-order exponential model governed by two key parameters (rate constant and equilibrium concentration, i.e., k_FBS and q_e). Heterotrophic plate count, flow cytometry, and scanning electron microscopy analyses confirmed culturability loss, membrane damage, elevated intracellular ROS levels, and morphological disruption. Pilot-scale experiments using aged cast iron pipes validated persuasive real-world applicability with minimal turbidity fluctuation and persistent FBS presence throughout the process. Overall, the PMS/Br^- system offers a low-halide, high-efficiency disinfection solution with sustained microbial activity against resistant microorganisms, making it a promising candidate for water infrastructure cleaning and sanitization.