title: Removal of natural estrogens and their conjugates in municipal wastewater treatment plants: a critical review.
abstract: This article reviews studies focusing on the removal performance of natural estrogens in municipal wastewater treatment plants (WWTPs). Key factors influencing removal include: sludge retention time (SRT), aeration, temperature, mixed liquor suspended solids (MLSS), and substrate concentration. Batch studies show that natural estrogens should biodegrade well; however, batch observations do not always agree with observations from full-scale municipal WWTPs. To explain this discrepancy, deconjugation kinetics of estrogen conjugates in lab-scale studies were examined and compared. Most estrogen conjugates with slow deconjugation rates are unlikely to be easily removed; others could be cleaved in WWTP settings. Nevertheless, some estrogens cleaved from their conjugates may be found in treated effluent, because deconjugation requires several hours or longer, and there is insufficient rest time for the biodegradation of the cleaved natural estrogens in the WWTP. Therefore, WWTP removals of natural estrogens are likely to be underestimated when estrogen conjugates are present in raw wastewater. This review suggests that biodeconjugation of estrogen conjugates should be enhanced to more effectively remove natural estrogens in WWTPs.
authors.affiliation: †College of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong China.
authors.forename: Ze-hua
authors.initials: ZH
authors.lastname: Liu
authors.affiliation: †College of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong China.
authors.forename: Gui-ning
authors.initials: GN
authors.lastname: Lu
authors.affiliation: †College of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong China.
authors.forename: Hua
authors.initials: H
authors.lastname: Yin
authors.affiliation: †College of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Dang
authors.affiliation: §Swette Center for Environmental Biotechnology, Biodesign Institute at Arizona State University, Tempe, Arizona 85287-5701, United States.
authors.forename: Bruce
authors.initials: B
authors.lastname: Rittmann
mesh_terms: D004784:Environmental Monitoring; D004967:Estrogens / Q000032:analysis*; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D004967:Estrogens; D062065:Wastewater; D014874:Water Pollutants, Chemical