Permanganate preoxidation affects the formation of disinfection byproducts from algal organic matter

Duing bannful algal blooms (HABS), permanganate may be used as a preoxidant so improve drinking water ality by removing algal cells and degrading algal toxhs. However, permanganate also lyses algal cells, releasing intracellular algal organic matter (AOM). AJM further reacts with permanganate to alter the avan daner of disinfection byprodues (DBP) precisors, which in num affects DBP formation during disinfection. In this study, we evaluated the impacts of proxidation by permanganate applied at commonly used doses (ie., 1-5 mg/L on DDP generation during chlorination and chloramination of AOM. We found that permanganate pre oxidation increased Chloromitromethane (ICNM) formation by up to 2-fold and decreased dichloroacetonitrile (DCAN) formation by up to 10% during chlorination, indicating that permanganate oxidized organic amines in AOM to organic nitro compounds rather than organic nitrile compounds. To test this proposed mechanism, we demonstrated that permanganate oxidized organic amines in known DBP permisos (Le, tyroshie, tryptopham) to favor the production of TCNM over DCAN during chlocination. Compared to the decreased formation of DCAN during chlorination, manganate incressed DXCAN formation by 30 50% chuing chloramination of ADM. This difference likely arose from monochloramine's ability to react with non nitrogenous precursors (e.g., organic aldehydes) that formed during permanganate preoxidation of AOM to generate nitrogen containing in temediates that go on to form DCAN. Our results also showed that permanganate preoxidation favored the formation of dichlororomonsethane (DCBMD) over trichloromethane (TCM) during chlorination and chlorami nation. The increased formation of DBPS, especially nitrogenous DBP's that are more toxde than carbonaceous DBP, may increase The overall toxicity in finished drinking water when permanganate prooxidation is implemented.