Ozone, oxalic acid, and organic matter molecular weight - Effects on coagulation

Ozonation breaks long chain natural organic matter (NOM) into smaller, more oxygenated compounds such as oxalic acid. The purpose of this study was to evaluate the effects of such transformations on coagulation in high dissolved organic carbon synthetic waters with model particles. Results indicate that the presence of oxalic acid adversely affects the removal of turbidity and organic carbon by coagulation and filtration. The results also show that larger (higher molecular weight) organic matter is easier to remove by coagulation than lower molecular weight organic matter. In both cases, ozonation results in an increase in the optimum coagulant dose or a decrease in the amount of turbidity and TOC removal at a given coagulant dose.