Comparison of UV based advanced oxidation processes (UV/Periodate, UV/ Peroxydisulfate, UV/NaClO, and UV/H2O2) for inactivating Escherichia coli in marine water

Escherichia coli ( E. coli ) contamination in marine aquaculture represents a major financial risk. This study investigated the efficacy of ultraviolet-based advanced oxidation processes (UV-AOPs) employing a 10 W ultraviolet lamp and 1 mM oxidant to inactivate E. coli in marine aquaculture water. Within just two minutes, all UV-AOPs significantly enhanced inactivation compared to UV alone (2.21 log), with UV/Periodate (UV/PI, 6.96 log), UV/Peroxydisulfate (UV/PDS, 4.20 log), UV/NaClO (3.80 log) and UV/H₂O₂ (6.04 log) demonstrating superior performance. Radical quenching experiments confirmed that the generated reactive species were pivotal in promoting inactivation. Further microbial characterization revealed that the AOPs compromised cellular integrity by disrupting membrane structures and damaging intracellular DNA. Moreover, the processes effectively inhibited the photoreactivation of E. coli , a key mechanism for pathogen regrowth. The feasibility of AOPs for practical application was substantiated through pathological analysis of fish, confirming their safety and efficacy.