Occurrence and fate of androgens, estrogens, glucocorticoids and progestagens in two different types of municipal wastewater treatment plants

The occurrence and fate of fourteen androgens, four estrogens, five glucocorticoids and five progestagens were investigated in two different types of wastewater treatment plants (Plant A: activated sludge with chlorination, and Plant B: oxidation ditch with UV) of Guangdong province, China. 14, 14, and 10 of 28 target compounds were detected in the influent, effluent and dewatered sludge samples with the concentrations ranging from below 1.2 +/- 0.0 ng L-1 (stanozolol) to 1368 +/- 283 ng L-1 (epi-androsterone), below 1.0 +/- 0.0 ng L-1 (progesterone) to 23.1 +/- 1.0 ng L-1 (5 alpha-dihydrotestosterone), 1.0 +/- 0.1 ng g(-1) (estrone) to 460 +/- 4.4 ng g(-1) (5 alpha-dihydrotestosterone), respectively. The concentrations of total androgens (1554-1778 ng L-1 in influent, 13.3-47.8 ng L-1 in effluent, 377-923 ng g(-1) in dewatered sludge) were much higher than those of total estrogens (41.5-60.2 ng L-1 in influent, 5.6-13.5 ng L-1 in effluent, 13.9-57.8 ng g(-1) in dewatered sludge), glucocorticoids (171-192 ng L-1 in influent, 2.2-6.3 ng L-1 in effluent, N.D.-4.4 ng g(-1) in dewatered sludge), and progestagens (39.6-40.5 ng L-1 in influent, 6.9-12.1 ng L-1 in effluent, N.D. in dewatered sludge) in these two WWTPs. According to mass balance analysis, the removal rates of most target steroids in Plant A had exceeded 90%, while those in Plant B for nearly half of detected target steroids were lower than 80%. It is obvious that the treatment capacity of the activated sludge system (Plant A) is superior to the oxidation ditch (Plant B) in the degradation of steroids in sewage treatment systems. Androgens, estrogens and progestagens were mainly removed by sorption and degradation, while the reduction of glucocorticoids was primarily due to degradation.