School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.
Water Res. 2013 Sep 15;47(14):5298-306. doi: 10.1016/j.watres.2013.06.009. Epub 2013 Jun 13.
The occurrences, transformation of antibiotics in biological wastewater treatment plants have attracted increasing interests. However, roles of extracellular polymeric substances (EPS) of activated sludge on the fate of antibiotics are not clear. In this study, the roles of EPS in the migration and removal of one typical antibiotic, sulfamethazine (SMZ), in activated sludge process were investigated. The interaction between EPS and SMZ was explored through a combined use of fluorescence spectral analysis, laser light scattering and microcalorimetry techniques. Results show that SMZ interacted with the proteins in EPS mainly with a binding constant of 1.91 × 10(5) L/mol. The binding process proceeded spontaneously, and the driving force was mainly from the hydrophobic interaction. After binding, the structure of EPS was expanded and became loose, which favored the mass transfer and pollution capture. The removal of SMZ was influenced by interaction with EPS. SMZ could be effectively adsorbed on EPS, which accounted for up to 61.8% of total SMZ adsorbed by sludge at the initial adsorption stage and declined to around 35.3% at the subsequent biodegradation stage. The enrichment of SMZ by EPS was beneficial for SMZ removal and acquisition by microbes at the subsequent biodegradation stage.
抗生素在生物污水处理厂中的存在和转化引起了越来越多的关注。然而，活性污泥中胞外聚合物（EPS）对抗生素命运的作用尚不清楚。本研究通过荧光光谱分析、激光光散射和微量热技术的综合应用，考察了 EPS 在活性污泥工艺中迁移和去除典型抗生素磺胺甲恶唑（SMZ）过程中的作用。结果表明，SMZ 主要与 EPS 中的蛋白质发生相互作用，结合常数为 1.91×10(5) L/mol。结合过程是自发进行的，驱动力主要来自疏水相互作用。结合后，EPS 的结构扩展变得松散，有利于传质和污染物捕获。SMZ 的去除受到与 EPS 相互作用的影响。SMZ 可以有效地被 EPS 吸附，在初始吸附阶段，被污泥吸附的总 SMZ 中高达 61.8%是通过 EPS 吸附的，而在随后的生物降解阶段则下降到约 35.3%。EPS 对 SMZ 的富集有利于微生物在随后的生物降解阶段对 SMZ 的去除和获取。
