The occurrence, fate, and distribution of natural and synthetic hormones in different types of wastewater treatment plants in Iran

Over the past few years, the presence of steroid estrogens in the environment has become a major concern. In this study, the concentrations of estrone (E1), 17β-estradiol (E2), and 17α-ethinyl estradiol (EE2) were measured in some wastewater treatment plants (WWTPs) in Iran. These samples were collected from the municipal, rural, livestock, commercial, and hospital WWTPs, extracted by dispersive liquid-liquid micro extraction (DLLME) technique, derivatized, and detected by GC/MS. In these treatment plants, various processes including conventional activated sludge (CAS), aerated lagoon (AL), moving bed biofilm reactor (MBBR), and activated sludge with wetland (AS + WL) are used. The highest concentration of hormones was observed in the influents and effluents of livestock, municipal, commercial, and hospital WWTPs, respectively. The maximum elimination rate was obtained in MBBR followed by AS + WL, CAS and AL. The biodegradation and adsorption rates along with adsorption coefficients of lg kd and lg koc were measured for all target compounds.