Process Considerations for the Reduction of Endocrine Disruption Potential at Wastewater Treatment Facilities

Several full-scale wastewater facilities were monitored for potential endocrine disruption potential using the yeast estrogen screen (YES) assay. The YES assay utilizes a transgenic yeast strain containing the human estrogen receptor (hER) and reporter genes. The working definition of endocrine disrupting potential in this paper is any compounds which effectively binds to the human estrogen receptor causing activation of the reporter gene. Samples were taken across different unit processes in order to assess their impact on endocrine disruption potential. The majority of estrogenic activity was associated with the biosolids. Anaerobic digestion appeared to increase specific estrogenic activity of the biosolids while aerobic digestion and pelletizing appeared to decrease activity. An increase in sludge retention time (SRT) increased the specific estrogenic activity of the mixed liquor suspended solids (MLSS). There was a difference in specific estrogenic activity in the MLSS between conventional and membrane facilities. Results of these experiments are presented here. Future research efforts should be dedicated to understanding binding mechanisms between biological solids and organic micropollutants.