Integrated adsorption, oxidation and biodegradation for treating emerging contaminants in wastewater and water

Abstract

Combination of adsorption and chemical or photocatalytic pretreatment with subsequent biodegradation demonstrates high potential for treating wastewater containing emerging contaminants (ECs). Removal of ECs, such as endocrine disrupting compounds and pharmaceuticals in wastewater-treatment plants was found to be rather low and persistent. Advanced oxidation processes (AOPs) are used widely for the removal of organic pollutants including ECs not treated by conventional techniques owing to their high chemical stability and/or low biodegradability. Although AOPs for complete mineralization is usually costly, its combination with biological treatment can reduce operating costs and achieve complete mineralization of organic pollutants. The chemical or photocatalytic degradation of bisphenol A (BPA), a representative endocrine disruptor and sulfamethoxazole (SMX), a representative pharmaceutical, was carried out in aqueous suspension using either activated carbon supported iron catalyst or biochar supported TiO2 photocatalyst under UV irradiation. The photocatalytic pre-treatment using biochar-TiO2 led to partial oxidation of biologically persistent part of BPA or SMX to produce biodegradable products.