REMOVAL OF ENDOCRINE DISRUPTING COMPOUNDS AND ESTROGENIC ACTIVITY FROM SECONDARY EFFLUENTS DURING TiO2 PHOTOCATALYSIS

摘要

This paper presents the results of application of TiO_2 photocatalysis in advanced wastewater treatment to simulate the removal of endocrine disrupting compounds (i.e., bisphenol A, nonylphenol, estrone, and 17a-estradiol) and estrogenic activity from secondary effluents of a municipal wastewater treatment plant, aiming to evaluate the possibility of application of photocatalysis for advanced wastewater treatment. The removal efficiencies of alkyl-hydroxybenzene (bisphenol A, nonylphenol) by traditional process in wastewater treatment plant are more sensitive to temperature than steroid hormones (estrone, and 17a-estradiol), resulting in a risk of effluent insecurity. All the targeted EDCs in secondary effluent could be totally degraded by TiO_2 photocatalysis within 60 min except BPA (92% removal), following pseudo first-order kinetics. The estrogenic activity, expressed as the E2 equivalent concentration (EEQ), was also totally removed during the same process. The mechanisms for the photocatalytic removal of EDCs and estrogenic activity were proposed according to the experimental results. When EDCs reacted with hydroxyl radicals, aromatic rings were cleaved, resulting in a decreased estrogenic activity. The findings suggest that TiO_2 photocatalysis is an effective method for removal of certain EDCs and estrogenic activity from secondary effluents and can be used for advanced wastewater treatment.