Department of Environmental Engineering, Technical University of Denmark (DTU) , Bygningstorvet, Bygning 115, 2800 Kgs. Lyngby, Denmark.
Process and Systems Engineering Center (PROSYS), Department of Chemical and Biochemical Engineering, Technical University of Denmark , Building 229, 2800 Kgs. Lyngby, Denmark.
Environ Sci Technol. 2017 Sep 19;51(18):10572-10584. doi: 10.1021/acs.est.6b06277. Epub 2017 Aug 28.
In-sewer transformation of drug biomarkers (excreted parent drugs and metabolites) can be influenced by the presence of biomass in suspended form as well as attached to sewer walls (biofilms). Biofilms are likely the most abundant and biologically active biomass fraction in sewers. In this study, 16 drug biomarkers were selected, including the parent forms and the major human metabolites of mephedrone, methadone, cocaine, heroin, codeine, and tetrahydrocannabinol (THC). Transformation and sorption of these substances were assessed in targeted batch experiments using laboratory-scale biofilm reactors operated under aerobic and anaerobic conditions. A one-dimensional model was developed to simulate diffusive transport, abiotic and biotic transformation, and partitioning of drug biomarkers. Model calibration to experimental results allowed estimating biotransformation rate constants in sewer biofilms, which were compared to those obtained for suspended biomass. Our results suggest that sewer biofilms can enhance the biotransformation kinetics of most selected compounds. Through scenario simulations, we demonstrated that the estimation of biotransformation rate constants in biofilm can be significantly biased if the boundary layer thickness is not accurately estimated. This study complements our previous investigation on the transformation and sorption of drug biomarkers in the presence of only suspended biomass in untreated sewage. A better understanding of the role of sewer biofilms-also relative to the in-sewer suspended solids-and improved prediction of associated fate processes can result in more accurate estimation of daily drug consumption in urban areas in wastewater-based epidemiological assessments.
在污水管道中，药物生物标志物（排泄的母体药物和代谢物）的转化可能会受到悬浮生物量以及附着在污水管道壁上的生物膜的影响。生物膜可能是污水中最丰富和最具生物活性的生物量部分。在这项研究中，选择了 16 种药物生物标志物，包括甲卡西酮、美沙酮、可卡因、海洛因、可待因和四氢大麻酚（THC）的母体形式和主要人体代谢物。使用实验室规模的生物膜反应器，在需氧和厌氧条件下进行靶向批量实验，评估了这些物质的转化和吸附。开发了一个一维模型来模拟药物生物标志物的扩散传输、非生物和生物转化以及分配。通过将模型校准到实验结果，可以估计污水生物膜中的生物转化速率常数，并将其与悬浮生物量获得的速率常数进行比较。我们的结果表明，污水生物膜可以增强大多数选定化合物的生物转化动力学。通过情景模拟，我们证明如果不能准确估计边界层厚度，那么在生物膜中估计生物转化速率常数可能会产生显著偏差。本研究补充了我们之前关于仅在未经处理的污水中存在悬浮生物量时药物生物标志物的转化和吸附的研究。更好地了解污水生物膜的作用（相对于污水中的悬浮固体）以及改进对相关命运过程的预测，可以更准确地估计基于废水的流行病学评估中城市地区的每日药物消耗量。
