Ozonation and photocatalysis of waste water contaminated with 17 alpha ethinylestradiol EE2 in chambery France

Abstract

Wastewater treatment plants (WWTPs) receive a large spectrum of endocrine disrupting compounds (EDCs). The classic treatment of water does not remove these molecules. They are discharged into rivers. We chose to verify the efficiency of ozonation and photocatalysis for a waste water contaminated with three concentrations of EE2 and extracted from a WWTP situated in Chambery-France. Water samples were filtered on nitrocellulose filters (porosity = 0.45µm) and conserved at 4°C.Water samples doped with EE2 were analyzed using high-performance liquid chromatography (HPLC, Hewlett-Packard,1050 series) with a fluorescence detector (HP 1064A) (λ exc = 210 nm, λ issue = 309 nm). The consumption of ozone required to degrade small quantities of ethinylestradiol is extremely high. In fact, to eliminate 1.55x10-2 nmol.L-1 or 4.6 ng.L-1 of EE2, a molar quantity of ozone of 800,000 times bigger should be added to the water. This result is caused by the presence of organic substances reactive in waste water which enter in competition with the reaction between EE2 and O3. For the photocatalysis, in only 4 hours, 23% of EE2 is degraded. The slow degradation of EE2 is caused by, the presence of the organic compounds, the low luminous flux and the small concentration of TiO2 P25 (mg.L-1).