The presence of sulfamethoxazole (SMX) can adversely affect the anaerobic digestion process, reducing the efficiency of wastewater treatment and methane production. In this study, the addition of exogenous nanoscale zero-valent iron (nZVI) enhanced the efficient treatment of SMX and promoted the energy recovery from antibiotic wastewater. The results showed that the removal of SMX in the reactor pairs with 0.5 g/L nZVI increased by 20 %, 35 %, and 27 %, and the methane production increased by 21.6 %, 40.9 %, and 26.6 %, respectively, compared with the control reactor at different SMX influent concentrations (50, 100, and 200 mg/L). The microbial community distribution indicated that the nZVI facilitated efficient cooperation between acid-producing and methanogens by regulating the relative abundance of functional bacteria, such as Anaerolinea and Methanothrix. Meanwhile, nZVI can effectively facilitate the direct interspecies electron transfer (DIET) and enhance electron transport system (ETS) activity by functioning as a conductive particle and increasing the abundance of genes related to cytochrome C (Cyt C) and type IV pili. In addition, nZVI can reduce the risk of antibiotic resistance genes (ARGs) transmission by decreasing the relative abundance of ARGs. In summary, this study could provide new insights and theoretical support for efficient anaerobic bioremediation and energy recovery of antibiotic wastewater containing SMX.

中文翻译：

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纳米级零价铁对废水净化和能源生成的同时影响：磺胺甲噁唑降解和甲烷生成的机制


磺胺甲噁唑 （SMX） 的存在会对厌氧消化过程产生不利影响，降低废水处理和甲烷生产的效率。在本研究中，外源纳米零价铁 （nZVI） 的添加增强了 SMX 的高效处理，并促进了抗生素废水中的能量回收。结果表明，与对照反应器相比，不同 SMX 进水浓度（50、100 和 200 mg/L）的 SMX 对中 SMX 的去除率分别提高了 20 %、35 % 和 27 %，甲烷产量分别增加了 21.6 %、40.9 % 和 26.6 %。微生物群落分布表明，nZVI 通过调节功能性细菌（如厌氧菌和甲烷菌）的相对丰度，促进了产酸菌和产甲烷菌之间的有效合作。同时，nZVI 可以通过充当导电粒子并增加与细胞色素 C （Cyt C） 和 IV 型菌毛相关的基因的丰度，有效地促进直接种间电子转移 （DIET） 并增强电子传递系统 （ETS） 活性。此外，nZVI 可以通过降低 ARG 的相对丰度来降低抗生素耐药基因 （ARGs） 传播的风险。综上所述，本研究可为含 SMX 抗生素废水的高效厌氧生物修复和能量回收提供新的见解和理论支持。