Microcystins (MCs), the most frequently detected group of cyanobacterial toxins in drinking water, pose a major human health hazard due to their prevalence and high toxicity. UV/chlorine process was evaluated as a potentially practical and effective process for the removal of MCs in water supplies. By far, the information on the elimination of less-studied MCs, such as MC-LA, MC-RR, MC-YR, by UV/chlorine is limited. Therefore, degradation kinetics and mechanisms of MC variants by chlorination and UV/chlorine process were investigated in this study. The UV/chlorine process showed a significant synergistic effect on the degradation of all studied MCs as shown by the magnitude of degradation kinetics. The variations of degradation kinetics with pH for MC-LR, MC-RR, MC-LA, and MC-YR were markedly different, indicating that the variable amino acids in the structure of MCs influenced the degradation kinetics. Rapid degradation of MCs was observed with varying pH, even at high pH 8-10, which indicated the UV/chlorine could be employed to treat water from several lakes contaminated with HABs after proper pre-treatment in engineered water treatment plants. The role of water matrix was investigated and the results showed parameters such as presence of Cl-, HCO3-, and natural organic matter (NOM) exhibited different effects on the degradation of MC-RR.

Destruction of microcystin variants by UV/chlorine process: Influence of variable amino acids on the degradation kinetics and reaction mechanism

256th National Meeting (2018)

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