Abstract
Abstract
This study investigated the photocatalytic removal of endocrine-disrupting compounds (EDCs), estrogenic activity, and Escherichia coliform (E. coli) in secondary effluents from a wastewater treatment plant in a cylindrical photocatalytic reactor. Its application for advanced wastewater treatment processes was evaluated. Estrone, 17α-estradiol, estriol, nonylphenol, and bisphenol A were chosen as target EDCs because of their high prevalence in wastewater. EDCs, estrogenic activity, and E. coli in the secondary effluent were rapidly removed within 100 min of TiO2 photocatalysis. Reactor performance was enhanced significantly by TiO2 photocatalysis compared with UV photolysis. Filtration was evaluated as a pretreatment method in TiO2 photocatalysis by comparing the reduction rate of estrogenic activity and E. coli in filtered samples with unfiltered wastewater samples. The inactivation rate of E. coli increased significantly after filtration, whereas the estrogenic activity reduction rate only slightly increased. This could be attributed to the partial impeding effects of suspended solids on photosensitive reactions induced by humic acid during photocatalysis. TiO2 photocatalysis with filtration pretreatment can be an effective method for advanced wastewater treatment. This is the first report on the removal of EDCs and E. coli from secondary effluents using TiO2 photocatalysis as an advanced wastewater treatment process.
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