Biological treatment of estrogenic substances.

The fate and behavior of estrogenic substances in various biological wastewater treatment processes and several advanced sewage treatment processes were examined. The removal of 17beta-estradiol (E2), estrone (E1) and estriol (E3) was investigated by using a pilot-scale activated sludge plant supplied with domestic sewage. Several sewage treatment plants adopting the activated sludge process were evaluated for the removal of estrogenic substances using an in vitro recombinant yeast assay and chemical analysis. The results indicated that E2 significantly contributed to estrogen-like activity particularly in secondary treated effluents. The removal rate of E2 was found to be sufficiently high throughout a one-year study on estrogens in domestic sewage, whereas E1 often remained in the effluent. The optimization of operational conditions based on E1 removal is important for reducing estrogenic activity in treated water.