Characterization of Oxidation processes: ozonation and the AOP O₃/H₂O₂

The influence of water quality parameters (dissolved organic matter and alkalinity) on the efficiency of the ozone/hydrogen peroxide (O 3 /H 2 O 2 ) advanced oxidation process (AOP) relative to the corresponding conventional ozonation process was investigated. In natural waters with a high natural organic matter content (≥3 mg/L), O 3 decomposition is controlled by radical‐type chain reactions. Thus, the overall OH radical oxidation capacity is nearly independent if conventional ozonation is replaced by O 3 /H 2 O 2 AOP. In contrast, when the organic matter content in the natural water is low (≤1 mg/L), the addition of H 2 O 2 considerably enhances the oxidation capacity by OH radicals. A constant ratio between the OH radical and O 3 concentration ( R ct ) was found during both treatments, making it possible to predict the oxidation of micropollutants with O 3 and OH radicals if the rate constants of both oxidants are known. The oxidation of atrazine during ozonation and the combined process O 3 /H 2 O 2 could be accurately predicted in natural waters.