The objective of this study was to assess the removal efficiencies of secondary wastewater treatment processes for compounds causing endocrine disrupting activity. The study used bioassays and chemical measurements, such as gas chromatography with mass spectrometry and enzyme immunosorbent assays. A total of seven full‐scale water reclamation facilities using different unit operations and two pilot‐scale membrane bioreactors were examined. Findings of this study imply that estrogenic disrupting activity in primary effluent is mainly caused by two steroidal hormones (17β‐estradiol and estriol) and, to a lesser extent, by synthetic chemicals, such as bisphenol A, 4‐nonylphenol, and 4‐tert‐octylphenol. During secondary treatment, steroidal hormones were removed to a higher degree than nonylphenol and bisphenol A. The total estrogenic activity was removed by an average of 96%. The remaining concentrations of targeted steroids in secondary effluents, except for estriol, still had the potential to elicit a positive response in the human breast cell cancer assay. For the majority of facilities, the remaining activity was likely attributed to residual concentrations of two steroidal hormones (17β‐estradiol and estriol).

The objective of this study was to assess endocrine disrupting activity in water reclamation systems with bioassays and chemical measurements. A total of seven full-scale water reclamation facilities employing different unit operations and two pilot-scale membrane bioreactors were examined. Findings of this study imply that endocrine disrupting activity in primary effluent is mainly caused by steroidal hormones and to a lesser extent by synthetic chemicals such as bisphenol A, nonylphenol, and octylphenol. During secondary treatment, steroidal hormones were removed to a higher degree than nonylphenol, whereas bisphenol A and octylphenol were entirely removed. The total estrogenic activity was removed by an average of 96 percent. The remaining concentrations of some steroids in secondary effluents still had the potential to cause an endocrine disrupting effect in the human breast cell cancer assay. For the majority of facilities the remaining activity is likely attributed to residual concentrations of steroidal compounds.

The objective of this study was to assess endocrine disrupting activity in water reclamation systems with bioassays and chemical measurements. A total of twelve full-scale water reclamation facilities employing different unit operations and three pilot-scale membrane bioreactors were examined. Findings of this study imply that advanced treatment processes such as reverse osmosis and powdered activated carbon treatment would be very efficient in removing endocrine disrupting activity. While low pressure UV disinfection is ineffective in removing EDCs, medium pressure UV achieved a 50 percent reduction of phenolic EDCs (nonylphenol, tert-octylphenol). MBR systems studied in this investigation were not found to remove EDCs and endocrine disrupting activity to a level statistically greater than conventional secondary treatment.