甾体激素在污水处理厂中的赋存特征和行为归趋

污水处理厂是控制甾体激素环境排放的重要屏障之一,研究不同种类甾体激素在不同工艺污水处理厂中的赋存特征和行为归趋是提高污水处理厂对甾体激素处理效能的重要基础.对无锡市两个污水处理厂各工艺段中22种甾体激素的赋存情况进行8个月的监测,比较了厌氧-缺氧-好氧工艺(A²/O)和倒置A²/O工艺的处理效果.结果表明,甾体激素的进出水总浓度分别为27.7~256.8 ng ·L^-1和5.7~211.0 ng ·L^-1,剩余污泥中激素总含量为36.3~123.6 ng ·g^-1,主要检出雄酮、雄烯二酮、雌酚酮、雌三醇和孕酮.进出水中大多数激素的浓度随降雨量和温度的升高而略有降低的趋势,而冬夏的季节差异未对甾体激素的去除率产生显著影响.污水厂的二、三级处理工艺对激素的去除效果优于一级处理,倒置A²/O和传统A²/O相比对甾体激素的去除并未表现出明显的优势.甾体激素在污水和污泥间的分配系数lg Koc为2~4.5,在厂A中的lg Koc略高于厂B,激素的泥水分配可能影响其处理效果.

Occurrence and Fate of Steroid Hormones in Sewage Treatment Plants

Sewage treatment plants (STPs) are one of the crucial barriers for the environmental emission of steroid hormones. Insights into the occurrence and fate of different categories of steroid hormones in STPs could provide theoretical support for improving steroid removal by STPs. The present study investigated 22 steroid hormones in each treatment process of two STPs located in Wuxi via eight monthly sampling campaigns and compared the efficacy of Anaerobic-Anoxic-Aerobic (A²/O) and reversed A²/O treatments. The results showed that the total steroid concentrations in the influent and effluent were 27.7-256.8 ng·L^-1 and 5.7-211.0 ng·L^-1, respectively, and 36.3-123.6 ng·g^-1 in the excess sludge. Androsterone, androstenedione, estrone, estriol, and progesterone were the main species detected in the STPs. The concentrations of most steroids increased with the rise of rainfall and temperature, whereas the removal rates were not significantly different between winter and summer. Secondary and tertiary treatment processes showed better performance in steroid removal compared with that in the primary treatment; however, reversed A²/O did not show advantages over traditional A²/O. The organic-normalized partition coefficients (lg Koc) of steroids ranged between 2 and 4.5. The values of lg Koc in STP A were slightly greater than those in STP B, indicating that the partition behavior of steroids may influence their treatment efficacies.