Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, #06-10, Singapore, 637141, Singapore.
School of Civil and Environmental Engineering, Nanyang Technological University, N1-01a-29, 50 Nanyang Avenue, Singapore, 639798, Singapore; Department of Chemical Engineering, Imperial College London, SW7 2AZ, UK.
Chemosphere. 2017 Mar;171:446-459. doi: 10.1016/j.chemosphere.2016.12.053. Epub 2016 Dec 21.
The effect of zinc oxide nanoparticles (ZnO NPs) on the performance of an anoxic-aerobic submerged membrane bioreactor (MBR), and the characterization of the soluble microbial products (SMPs) produced in the presence of ZnO NPs was evaluated. Continuous operation over 144 days showed that ZnO NPs at concentrations of 10 and 50 mg/L exerted a negative impact on chemical oxygen demand (COD) and nitrogen removal, although ZnO NPs were efficiently removed in the MBR (>92%). 10 and 50 mg/L ZnO NPs decreased COD removal substantially from 93.1± 0.6% to 90.1± 0.8% (<0.05) and 86.3± 2.3% (<0.05), respectively. Similarly, with 10 and 50 mg L ZnO NPs, the decreased in NHN removal was 8.1% and 21.1%, respectively. Exposure to 1, 10 and 50 mg/L ZnO NPs increased SMP concentrations by 12.8%, 42.4% and 51.5%, respecti. High performance size exclusion chromatograph (HP-SEC) analysis revealed that the presence of ZnO NPs caused a significant increase in high-molecular weight (MW) (583 kDa) SMPs at 1 and 10 mg/L ZnO NP concentration. A substantial decrease in the concentration of high-MW compounds in the MBR effluent was observed at the end of the experiment. Excitation emission matrix (EEM) fluorescence contours revealed that SMPs were dominated by amino acid-, tryptophan protein-, polyaromatic-, and polycarboxylate-type substances. The presence of ZnO NPs enhanced the production of amino acid-like (7.5-25.1%) and tryptophan protein-like compounds (31.7-38.1%), compared to the control (6.0-20.2% for amino acid-like compounds; and 28.5-36.7% for tryptophan protein-like compounds). In contrast, the fulvic and humic acid-like compounds decreased with exposure to ZnO NPs. This work may help better understanding the effect of nanoparticle exposure on wastewater treatment performance and SMP characteristics.
研究了氧化锌纳米粒子（ZnO NPs）对缺氧-好氧浸没式膜生物反应器（MBR）性能的影响，以及在 ZnO NPs 存在下产生的可溶性微生物产物（SMPs）的特性。连续运行 144 天后发现，浓度为 10 和 50 mg/L 的 ZnO NPs 对化学需氧量（COD）和氮去除有负面影响，尽管 MBR 中 ZnO NPs 的去除效率很高（>92%）。10 和 50 mg/L ZnO NPs 使 COD 去除率分别从 93.1±0.6%显著下降至 90.1±0.8%（<0.05）和 86.3±2.3%（<0.05）。同样，用 10 和 50 mg/L ZnO NPs 处理时，NHN 去除率分别降低了 8.1%和 21.1%。暴露于 1、10 和 50 mg/L ZnO NPs 会使 SMP 浓度分别增加 12.8%、42.4%和 51.5%。高分辨尺寸排阻色谱（HP-SEC）分析表明，在 1 和 10 mg/L ZnO NP 浓度下，ZnO NPs 的存在导致高分子量（MW）（583 kDa）SMPs 显著增加。实验结束时，观察到 MBR 出水中高 MW 化合物的浓度大幅下降。激发发射矩阵（EEM）荧光轮廓表明，SMP 主要由氨基酸、色氨酸蛋白、多环芳烃和多羧酸型物质组成。与对照相比（氨基酸类化合物为 6.0-20.2%；色氨酸蛋白类化合物为 28.5-36.7%），ZnO NPs 的存在增加了氨基酸样（7.5-25.1%）和色氨酸蛋白样化合物（31.7-38.1%）的产生。相反，富里酸和腐殖酸样化合物随着 ZnO NPs 的暴露而减少。这项工作可能有助于更好地理解纳米颗粒暴露对废水处理性能和 SMP 特性的影响。
