Effects of water matrix and ozonation on natural organic matter fractionation and corresponding disinfection by-products formation

In this study the influence of water matrix and oxidation treatment by ozone on natural organic matter (NOM) fractionation and corresponding disinfection by-products formation was investigated. Three water types were selected, based on their different NOM contents (5.16–9.85 mg/L dissolved organic carbon (DOC)) and structures (42–79% proportion of hydrophobic NOM fraction). It was determined that increasing the ozone dose (0.2–0.8 mg O₃/mg DOC) generally led to reductions in DOC (2–26%) and trihalomethane formation potential values (4–58%). Results of NOM fractionation showed that the reactivity of all the individual NOM fractions towards trihalomethane formation decreased after ozone oxidation (0.8 mg O₃/mg DOC) by 47–69%, relative to the raw waters.