Laboratory of Biological Processes (LPB), São Carlos School of Engineering, University of São Paulo (USP), 1100, João Dagnone Ave., Santa Angelina, 13563-120, São Carlos, São Paulo, Brazil.
Laboratory of Chromatography (CROMA), Institute of Chemistry of São Carlos, University of São Paulo (USP), 400, Trabalhador São-Carlense Ave., São Carlos, São Paulo, 13566-590, Brazil.
J Environ Manage. 2020 Nov 1;273:111170. doi: 10.1016/j.jenvman.2020.111170. Epub 2020 Aug 4.
Antibiotic compounds, notably sulfamethoxazole (SMX) and ciprofloxacin (CIP), are ubiquitous emerging contaminants (ECs), which are often found in domestic sewage. They are associated with the development of antimicrobial resistance. Operational parameters, e.g. organic loading rate (OLR), hydraulic retention time (HRT) and sludge retention time, may influence EC biodegradation in wastewater treatment plants. This study assessed the impact of the OLR variation on the biodegradation of CIP and SMX, applying two configurations of anaerobic fixed bed reactors: anaerobic packed bed biofilm reactor (APBBR) and anaerobic structured bed biofilm reactor (ASBBR). A significant reduction in the biodegradation of SMX (APBBR: 93-69%; ASBBR: 94-81%) and CIP (APBBR: 85-66%; ASBBR: 85-64%) was observed increasing OLR from 0.6 to 2.0 kgCOD m d. The decrease in the HRT from 12 to 4 h resulted in higher liquid-phase mass transfer coefficient (APBBR: k from 0.01 to 0.05 cm h; ASBBR: k from 0.07 to 0.24 cm h), but this was not enough to overcome the decrease in the antibiotic-biomass contact time on biofilm, thus reducing the bioreactors' performance. The ASBBR favored biomethane production (from 7 to 17 mLCH gVSS L d) and biodegradation kinetics (k from 1.7 to 4.2 and for SMX and from 2.1 to 4.8 L gVSS d for CIP) due to the higher relative abundance of the archaea community in the biofilm and the lower liquid-phase mass transfer resistance in the structured bed. CIP and SMX cometabolic biodegradation was associated to the hydrogenotrophic methanogenesis (mainly Methanobacterium genus) in co-culture with fermentative bacteria (notably the genera Clostridium, Bacillus, Lactivibrio, Syntrophobacter and Syntrophorhabdus). The anaerobic fixed bed biofilm reactors proved to be highly efficient in biodegrading the antibiotics, preventing them from spreading to the environment.
抗生素化合物，特别是磺胺甲恶唑（SMX）和环丙沙星（CIP），是普遍存在的新兴污染物（ECs），经常在生活污水中被发现。它们与抗药性的发展有关。操作参数，如有机负荷率（OLR）、水力停留时间（HRT）和污泥停留时间，可能会影响污水处理厂中 EC 的生物降解。本研究评估了 OLR 变化对 CIP 和 SMX 生物降解的影响，应用了两种厌氧固定床反应器配置：厌氧填充床生物膜反应器（APBBR）和厌氧结构化床生物膜反应器（ASBBR）。当 OLR 从 0.6 增加到 2.0 kgCOD m d 时，观察到 SMX（APBBR：93-69%；ASBBR：94-81%）和 CIP（APBBR：85-66%；ASBBR：85-64%）的生物降解率显著降低。HRT 从 12 小时缩短到 4 小时导致液相质量转移系数（APBBR：k 从 0.01 增加到 0.05 cm h；ASBBR：k 从 0.07 增加到 0.24 cm h）增加，但这不足以克服生物膜上抗生素-生物量接触时间的减少，从而降低了生物反应器的性能。ASBBR 有利于生物甲烷的产生（从 7 增加到 17 mLCH gVSS L d）和生物降解动力学（k 从 1.7 增加到 4.2 和 4.8 L gVSS d 用于 SMX 和 CIP），这是由于生物膜中古菌群落的相对丰度较高和结构化床中液相质量转移阻力较低。CIP 和 SMX 的共代谢生物降解与发酵细菌（特别是梭菌属、芽孢杆菌属、乳杆菌属、产氢菌属和互营菌属）共培养的产氢甲烷生成有关。厌氧固定床生物膜反应器在生物降解抗生素方面表现出很高的效率，防止它们扩散到环境中。
