Effect of H2O2 on UV Photo-Oxidation of Pharmaceuticals and Personal Care Products in Wastewater

This study investigates the effect of low levels of hydrogen peroxide (H2O2) on photo-oxidation of pharmaceuticals and personal care products (PPCPs) present in secondary effluent of a municipal wastewater treatment plant (WWTP). Experiments were conducted using two types of flow-through reactor systems: (1)three ultraviolet light (UV) reactors connected in series without a H2O2 addition, and (2)a UV reactor with a H2O2 addition. In the first part of this study, 38 PPCPs detected in secondary effluent were examined based on their degradability by UV in the presence and absence of H2O2. For the PPCPs that were not degraded to or below their detection level, the pseudo first-order photo-oxidation rate constants, k (s-1), were determined using a mathematical model developed for three continuously stirred tank reactors in series. The second part of the study investigated the kinetics of the selected PPCPs in the UV/H2O2 reactor. The effect of low concentrations of H2O2 on the photo-oxidation rate of PPCPs was quantified by the power function expression.