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Batch experiments were conducted to investigate the sorption and biodegradation behavior of 17b-estradiol (E2) at low mg Á L À1 levels by acclimated aerobic activated sludge as well as the effect of temperature on the sorption and biodegradation. Results showed that E2 was completely transformed after 2 h under aerobic conditions. E2 attenuation was achieved by sorption onto the sludge and the subsequent biodegradation by micro-organisms in the activated sludge. Sorption of E2 onto both the inactivated sludge and the activated sludge was well described by both the Freundlich and linear isotherms. The biodegradation of E2 by the acclimated activated sludge can be described by first-order reaction kinetics with the first-order reaction rate constant of 3.49 h À1 at 208C. The sorption isotherms and biodegradation kinetics indicated that partitioning played a dominant role in the sorption of E2 on the activated sludge. Temperature exerted significant effects on both the sorption and biodegradation of E2. The increase of temperature decreased the E2 sorption capacity on the sludge but enhanced E2 biodegradation rate. A new bacterial strain Pseudomonas aeruginosa TJ1 was isolated from the aerobic activated sludge, and it grew well when E2 served as the sole carbon and energy source.

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BACKGROUND: The synthetic estrogen 17α-ethinylestradiol (EE2) is of great environmental concern. Batch experiments were conducted to investigate the removal of EE2 by activated sludge under anaerobic conditions with or without nitrate. The effect of temperature on EE2 removal was also estimated.