17α-Ethinylestradiol and 17β-estradiol removal from a secondary urban wastewater using an RBC treatment system

The presence of micropollutants that include endocrine-disrupting compounds (EDC) in aquatic environments is currently one of the most relevant aspects of water quality due to their adverse effects on aquatic organisms and human health. From the several categories of EDC, 17β-estradiol (E2) is a natural hormone, which is prevalent in vertebrates, associated with the female reproductive system and maintenance of the sexual characters. 17α-Ethinylestradiol (EE2) is a synthetic hormone produced from the natural hormone E2 and is an essential component of oral contraceptives. These compounds are susceptible to bioconcentration and have high potential to bioaccumulation. Wastewater treatment plants are the main point source of E2 and EE2 into aquatic environments, but conventional wastewater treatment systems are not specifically designed for steroid removal. To overcome this problem, biological tertiary treatment may be a solution for the removal of emergent pollutants such as E2 and EE2. The main purpose of the present study is to provide a solution based on the optimization of a rotating biological contactor system to remove estrogens, specifically E2 and EE2, and to quantify their removal efficiency on different matrices, namely real wastewater and different synthetic wastewaters. All assays presented viable removal efficiencies for compound E2 with values always above 50%; real wastewater yielded the highest removal efficiencies. EE2 removal had better removal efficiencies with synthetic wastewater as feed solution, with removals above 15%, whereas the removal efficiency with real wastewater was inexistent.