Czech University of Life Sciences Prague, Faculty of Environmental Sciences, Department of Applied Ecology, Kamýcká 129, 165 21, Praha 6 Suchdol, Czech Republic; Silesian University of Technology, Faculty of Power and Environmental Engineering, Environmental Biotechnology Department, ul. Akademicka 2, 44-100, Gliwice, Poland; Silesian University of Technology, Biotechnology Centre, ul. B. Krzywoustego 8, 44-100, Gliwice, Poland.
Silesian University of Technology, Faculty of Power and Environmental Engineering, Environmental Biotechnology Department, ul. Akademicka 2, 44-100, Gliwice, Poland; Silesian University of Technology, Biotechnology Centre, ul. B. Krzywoustego 8, 44-100, Gliwice, Poland.
Chemosphere. 2021 Oct;280:130638. doi: 10.1016/j.chemosphere.2021.130638. Epub 2021 Apr 22.
The knowledge gaps regarding the degradation of sulfamethoxazole (SMX) in biofilters include the effect of aeration, constant feeding with readily biodegradable organic carbon and the presence of reactive media such as manganese oxides (MnOx). Thus, the goal of this study was to assess the removal of SMX in lab-scale biofilters with various operation variables: aeration, presence of MnOx as an amendment of filtering medium and the presence of readily biodegradable organic carbon (acetate). The sand used in the experiment as a filtering medium was previously exposed to the presence of SMX and acetate, which provided acclimation of the biomass. The removal of SMX was complete (>99%) with the exception of the unaerated columns fed with the influent containing acetate, due to apparent slower rate of SMX degradation. The obtained results suggest that bacteria were able to degrade SMX as a primary substrate and the degradation of this compound was subsequent to the depletion of acetate. The LC-MS/MS analysis of the effluents indicated several biotransformation reactions for SMX: (di)hydroxylation, acetylation, nitrosation, deamonification, S-N bond cleavage and isoxazole-ring cleavage. The relative abundance of transformation products was decreased in the presence of MnOx or acetate. Based on the Microtox assay, only the effluents from the unaerated columns filled with MnOx were classified as non-toxic. The results offer important implications for the design of biofilters for the elimination of SMX, namely that biofilters offer the greatest performance when fed with secondary wastewater and operated as non-aerated systems with a filtering medium containing MnOx.
关于磺胺甲恶唑 (SMX) 在生物滤池中降解的知识空白包括曝气、持续添加易生物降解有机碳以及存在反应性介质（如锰氧化物 (MnOx)）的影响。因此，本研究的目的是评估在具有各种操作变量的实验室规模生物滤池中去除 SMX：曝气、作为过滤介质添加剂的 MnOx 的存在以及易生物降解有机碳（乙酸盐）的存在。实验中用作过滤介质的沙子以前曾暴露于 SMX 和乙酸盐的存在下，这为生物量的驯化提供了条件。除了未曝气的柱子外，SMX 的去除率均达到 99%以上，这些柱子以含有乙酸盐的进水为进料，因为 SMX 的降解速度明显较慢。所得结果表明，细菌能够将 SMX 作为主要底物进行降解，并且在乙酸盐耗尽后，该化合物才会发生降解。对流出物的 LC-MS/MS 分析表明，SMX 发生了几种生物转化反应：（二）羟化、乙酰化、亚硝化、去氨化、S-N 键断裂和异恶唑环断裂。在 MnOx 或乙酸盐存在下，转化产物的相对丰度降低。根据 Microtox 测定，只有用 MnOx 填充的未曝气柱子的流出物被归类为无毒。这些结果为设计用于消除 SMX 的生物滤池提供了重要启示，即当以二级废水为进料并作为非曝气系统运行且过滤介质中含有 MnOx 时，生物滤池的性能最佳。
