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首页> 外文期刊>Environmental Science & Technology >Extracellular Polymeric Substances (EPS) in a Hybrid Growth Membrane Bioreactor (HG-MBR): Viscoelastic and Adherence Characteristics
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Extracellular Polymeric Substances (EPS) in a Hybrid Growth Membrane Bioreactor (HG-MBR): Viscoelastic and Adherence Characteristics

机译：混合生长膜生物反应器（HG-MBR）中的细胞外聚合物（EPS）：粘弹性和粘附特性

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摘要

Extracellular polymeric substances (EPS) comprising the microbial biofilms in membrane bioreactor (MBR) systems are considered the most significant factor affecting sludge viscoelastic properties as well as membrane fouling. Understanding the water chemistry effects on EPS viscoelastic, confor-mational, and adherence properties are critical for defining the microbial biofilm's propensity of fouling the membrane surface. In this study, EPS extracted from a hybrid growth membrane bioreactor (HG-MBR) were analyzed for their adherence, viscoelastic properties and size distribution using quartz crystal microbalance with dissipation monitoring (QCM-D) and dynamic light scattering (DLS), respectively. Also, adsorption characteristics of EPS extracted from different locations in the HG-MBR (bioreactor liquor, fluidized carriers, and membrane surface) were defined and linked to the extent of the total polysacchande content in the EPS. In accordance with the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, more EPS were adsorbed at higher ionic strength, lower pH and in the presence of calcium cations. Based on the QCM-D results, the calculated thickness of the EPS adsorbed layer was increased at lower ionic strength, higher pH, and only had a minor increase in the presence of calcium cations. The calculated shear modules and shear viscosity suggest that at lower pH and in the presence of calcium, EPS becomes more viscous and elastic, respectively. DLS analysis correlated to the QCM-D results: A decrease in the hydrodynamic radius of the EPS colloids was observed at lower pH, and in the presence of calcium, most likely attributed to intermolecular attraction forces. Based on this study, low pH and presence of calcium may induce flocs' stability that resist erosion in the MBRs, while on the other hand, these conditions may induce the formation of an elastic and viscous EPS layer fouling the ultrafiltration (UF) membrane.
机译：膜生物反应器（MBR）系统中包含微生物生物膜的细胞外聚合物（EPS）被认为是影响污泥粘弹性和膜污染的最重要因素。了解水化学对EPS的粘弹性，形态和附着特性的影响对于定义微生物生物膜污染膜表面的倾向至关重要。在这项研究中，分别使用具有耗散监测（QCM-D）和动态光散射（DLS）的石英晶体微量天平分析了从混合生长膜生物反应器（HG-MBR）提取的EPS的粘附性，粘弹性和尺寸分布。此外，还定义了从HG-MBR中不同位置（生物反应器液，流化载体和膜表面）提取的EPS的吸附特性，并将其与EPS中总多糖含量的程度联系起来。根据Derjaguin-Landau-Verwey-Overbeek（DLVO）理论，在较高的离子强度，较低的pH值和存在钙阳离子的情况下，会吸附更多的EPS。根据QCM-D结果，在较低的离子强度，较高的pH值下，EPS吸附层的计算厚度会增加，并且在钙阳离子存在的情况下只会略有增加。计算得出的剪切模量和剪切粘度表明，在较低的pH值和钙的存在下，EPS分别变得更粘和更有弹性。 DLS分析与QCM-D结果相关：在较低的pH值和存在钙的情况下，EPS胶体的流体动力学半径减小，这很可能归因于分子间吸引力。根据这项研究，低pH值和钙的存在可能会诱导絮凝物的稳定性，从而抵抗MBR中的侵蚀，而另一方面，这些条件可能会导致形成弹性且粘稠的EPS层，从而污染超滤（UF）膜。

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  • 来源
    《Environmental Science & Technology》 |2010年第22期|p.8636-8643|共8页
  • 作者

    WANG YING; FEI YANG; AMOS BICK; GIDEON ORON; MOSHE HERZBERG;

  • 作者单位

    Zuckerberg Institute for Water Research, Ben Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben Gurion, 84990, Israel;

    Zuckerberg Institute for Water Research, Ben Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben Gurion, 84990, Israel;

    Department of Industrial Engineering and Management, Jerusalem College of Technology, Jerusalem, Israel;

    Zuckerberg Institute for Water Research, Ben Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben Gurion, 84990, Israel;

    Zuckerberg Institute for Water Research, Ben Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben Gurion, 84990, Israel;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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  • 正文语种 eng
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