Fate of Estrogens and Estrogenic Potentials in Sewerage Systems

Release of steroid estrogens such as estrone (E1), 17-estradiol (E2), estriol (E3), and 17-ethinylestradiol (EE2) into the urban environment is of concern due to their prominent endocrine disrupting properties. This review focuses on the fate of estrogens as well as estrogenic potentials in the sewerage system starting from human excretion to municipal sewage treatment facilities. To examine the roles of different components in the municipal sewage treatment facilities in the removal of estrogens, data from 130 full-scale municipal sewage treatment plants (STPs) in 14 countries were summarized. Primary treatment systems removed less than 10% of the influent estrogens. Municipal STPs with the secondary biological treatment systems gave higher percentage removals of estrogens and estrogenic potentials than municipal STPs without secondary biological treatment systems. On average, municipal STPs with suspended growth systems gave better percentage removals of estrogens and estrogenic potentials than attached growth systems. Biological processes with nitrification had higher percentage removals than processes without nitrification. Microorganisms responsible for the degradation of estrogens under various conditions were also reviewed and presented.