Removal of Organic Micropollutants from Treated Municipal Wastewater by O3/UV/H2O2 in a UVA-LED Reactor

Abstract

ABSTRACT Organic micropollutants (OMPs) have been widely detected in the aqueous environment and their effect on the environment and human health has been studied. The removal of OMPs from effluents of a conventional urban wastewater treatment plant by ozonation as well as photo-enhancement of ozonation using UVA-LED panels and photolysis in the presence and absence of hydrogen peroxide was investigated. In a novel semi-technical reactor municipal wastewater was treated for 2 hours, using ozone – O3 (3 mg O3·L−1) and in combination with UVA-LED – O3/UV (peak wavelength 371 nm, 0.78 W·m−2) and in combination with UVA-LED and hydrogen peroxide – O3/UV/H2O2 (20 mg H2O2·L−1). The highest removal fractions for all OMPs were obtained with O3/UV/H2O2 (candesartan: 93.3%, irbesartan: 79.9%, 1 H-benzotriazole: 42.2%, hydrochlorothiazide: 40.8%, 4-/5-methyl-1 H-benzotriazole: 39%, and metoprolol: 24%) and with O3 (diclofenac: 87.2%, carbamazepine: 76.4%, and sulfamethoxazole: 53.5%). As a conclusion of the different AOP combinations of this study, UV photo-enhancement of ozonation has much more beneficial effects on OMP removal when it is combined with an additional H2O2 dosing.