Biodegradation of natural and synthetic estrogens in moving bed bioreactor

Estrogen hormones as a group of endocrine disruptive compounds (EDC) can interfere with endocrine system in humans and animals. The goal of this study was to investigate the elimination rate of Estrone (E1), 17β-estradiol (E2) and 17α-ethinyl estradiol (EE2) in Moving Bed Bioreactor (MBBR). These analytes extracted by Dispersive Liquid-Liquid Microextraction (DLLME) technique, followed by derivatization, and detected by GC/MS. Estrogen removal efficiency in MBBR improved at high solid retention times (SRTs), which notion is owing to development of nitrification. Estrogen specific removal rate was between 0.22-1.45 μg·(g VSS)− 1·d− 1 for natural and synthetic hormones. The adsorption rate was 0.9​%-3.2%, 0-1.3%, and 0.7%-5.7% for E1, E2, and EE2, respectively. In addition, the biodegradation rates were more than 95% for these compounds. These results illustrated that in MBBR, the biodegradation and the adsorption to biomass are considered as two significant routes for elimination of estrogenic compounds. As a whole, the deterioration rate of estrogens enhanced by MBBR compared to other biological wastewater treatment processes such as conventional activated sludge.