A pilot scale comparison of advanced oxidation processes for estrogenic hormone removal from municipal wastewater effluent

This study investigates the oxidation of selected endocrine disrupting compounds (estrone, 17β-estradiol, estriol and 17α-ethinylestradiol) during ozonation and advanced oxidation of biologically treated municipal wastewater effluents in a pilot scale. Selected estrogenic substances were spiked in the treated wastewater at levels ranging from 1.65 to 3.59 μg · L⁻¹. All estrogens were removed by ozonation by more than 99% at ozone doses ≥1.8 mg · L⁻¹. At a dose of 4.4 · mg L⁻¹ ozonation reduced concentrations of estrone, 17β-estradiol, estriol and 17α-ethinylestradiol by 99.8, 99.7, 99.9 and 99.7%, respectively. All tested advanced oxidation processes (AOPs) achieved high removal rates but they were slightly lower compared to ozonation. The lower removal rates for all tested advanced oxidation processes are caused by the presence of naturally occurring hydroxyl radical scavengers – carbonates and bicarbonates.