Ozone Oxidation of Endocrine Disruptors and Pharmaceuticals in Surface Water and Wastewater

The oxidative removal of a diverse group of trace organic contaminants from surface water and wastewater was evaluated using ozone (O3) and O3 combined with hydrogen peroxide (O3/H2O2). Target compounds included estrogenic and androgenic steroids, pharmaceuticals, pesticides, and industrial chemicals. Bench- and pilot- scale experiments were conducted with surface water spiked with the target compounds and wastewater effluent containing ambient concentrations of target compounds. Full-scale water treatment plants were sampled before and after ozonation to determine if bench- and pilot-scale results accurately predict full-scale removal. In both drinking water and wastewater experiments, the majority of target compounds were removed by greater than 90% at O3 exposures commonly used for disinfection. Atrazine, iopromide, meprobamate, and tris-chloroethylphosphate (TCEP) were the most recalcitrant compounds to oxidize using O3, with removals generally less than 50%. The addition of H2O2 for advanced oxidation was of little benefit for contaminant removal as compared to O3 alone. O3/H2O2 provided a marginal increase in the removal of dilantin, diazepam, DEET, iopromide, and meprobamate, while decreasing the removal efficacy of pentoxifylline, caffeine, testosterone, progesterone, and androstenedione. In wastewater experiments, O3 and O3/H2O2 were shown to remove in vitro estrogenicity. Collectively, these data provide evidence that O3 is a highly effective oxidant for removing the majority of trace organic contaminants from water.