人工湿地是一种简单、经济的生态型水处理技术，有研究表明利用人工湿地去除类固醇雌激素（SEs）具有一定的效果。天然雌激素雌酮（E1）和人工合成雌激素17-α乙炔基雌二醇（EE2）是环境中典型的类固醇雌激素，目前对人工湿地去除 SEs 的研究多集中在去除效率方面，机理研究缺乏。文章研究了不同浓度的典型根系分泌物成分草酸和咖啡酸对人工湿地去除模拟污水中E1和EE2的影响。结果表明：在进水流量为139μL·min-1，水力停留时间为5 d情况下，随着根系分泌物质量浓度的增加，9种不同类型的潜流湿地对E1平均去除率分别为34.3%（50 mg·L-1）、41.5%（100 mg·L-1）、55.8%（200 mg·L-1），对E2平均去除率分别为21.3%（50 mg·L-1）、29.6%（100 mg·L-1）、42.9%（200 mg·L-1），说明在一定范围内（50~200 mg·L-1），根系分泌物质量浓度的增加能促进人工湿地对E1、EE2的去除。利用荧光原位杂交(FISH)法分析湿地植物根区微生物数量。草酸、咖啡酸质量浓度各为50、100、200 mg·L-1时，细菌数量分别为6.0×106、7.2×106、11.2×106个·g-1。结果表明：根系分泌物质量浓度越高，湿地细菌数量越多，E1的生物降解作用越强。分析根系分泌物去除率与SEs去除率的关系发现：随着草酸、咖啡酸添加量的增加，其去除率逐渐降低，E1去除率增高。总之，根系分泌物共代谢可以增强人工湿地中SEs的降解作用。%Constructed wetland is a kind of simple, economic, ecological water treatment technology. Studies have shown that using artificial wetland to remove steroid estrogen has a certain effect. Estrone (E1), one of the natural steroidal estrogen hormones, and 17α-ethinylestradiol (EE2), one of the synthetic steroidal estrogens, are typical steroidal estrogens (SEs). Currently, researches on steroid estrogens in constructed wetland have only focused on removal efficiency while little about mechanisms. In this paper, the method of simulated wastewater was adopted to study the removal efficiencies of E1 and EE2 at different mass concentrations of typical root exudate components (Oxalic acid,caffeic acid) in constructed wetland. The results showed that with an influent flow of 139 μL·min-1 and a hydraulic retention time of 5 d, the removal efficiencies of E1 by nine different types of small subsurface flow constructed wetlands were 34.3% (50 mg·L-1), 41.5% (100 mg·L-1), 55.8% (200 mg·L-1) respectively, the removal efficiencies of E1 were 21.3%(50 mg·L-1), 29.6%(100mg·L-1), 42.9%(200 mg·L-1) respectively. It indicated that within a limit of 50 mg·L-1 to 200 mg·L-1, increased mass concentrations of root exudates could promote the removal of E1 and EE2 by the wetlands. The quantity distribution of wetland plant root-zone microorganism was analysed using fluorescence in situ hybridization (FISH). when the mass concentrations of oxalic acid and caffeic acid were 50 mg·L-1, 100 mg·L-1, 200 mg·L-1 respectively, bacterial amounts were 6.0×106 pcs·g-1, 7.2×106 pcs·g-1, 11.2×106 pcs·g-1. The results showed that the higher mass concentration of root exudates, the more wetland bacteria quantity, as well as the greater biodegradation of E1. The relationship between the removal rates of root exudates and SEs was analysed, which was found that with the increasing mass concentrations of oxalic acid and caffeic acid, the removal rate gradually reduced while removal rate of E1 increased. The research results above showed that the Co-metabolism of root exudates could enhance the degradation of steroidal estrogens in constructed wetland.
展开▼
