Interpretation of fouling characteristics of ultrafiltration membranes during the filtration of membrane bioreactor mixed liquor
Interpretation of fouling characteristics of ultrafiltration membranes during the filtration of membrane bioreactor mixed liquor
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DOI：
10.1016/j.memsci.2005.04.037
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发表时间：
2005-11-01
影响因子：
9.5
通讯作者：
Tak, TM
中科院分区：
文献类型：
--
作者：
Bae, TH;Tak, TM
采用相转化法制备了不同孔径的超滤膜，并以膜生物反应器（MBR）混合液为污染物，研究了膜的污染特性。将膜生物反应器污泥分成三部分：悬浮固体、胶体和溶质，并量化它们各自对膜污染的贡献，以评估污染发生的机制。膜表面形成的滤饼层是膜污染的主要机制，不可逆污染的发生率很小，可以忽略不计。污染程度与膜渗透性有很强的相关性。这意味着流体动力学条件是影响膜污染的重要因素。每个污泥馏分的污垢贡献似乎取决于颗粒尺寸，因为渗透阻力和回输速度都是颗粒尺寸相关的函数。溶质在滤饼层形成的起始中起着重要作用，因为它们在初始过滤后立即沉积在膜表面和孔壁上，但仅通过交叉流少量移出。悬浮固体一致地沉积到膜表面上，直到通量达到稳定状态，并且胶体表现出与溶质和悬浮固体之间的中间状态相称的特性。事实上，发现悬浮A固体是结垢过程的主要贡献者。然而，每个污泥组分对膜污染的相对贡献随膜的渗透性而变化，也随水动力条件而变化。(c)2005 Elsevier B.V.保留所有权利。
In this study, ultrafiltration (UF) membranes with various pore sizes were prepared by the phase inversion method, and their fouling characteristics were investigated with membrane bioreactor (MBR) mixed liquor. MBR sludge was fractionated into three parts, suspended solids, colloids and solutes, and their individual contributions to membrane fouling were quantified in order to asses the mechanisms by which fouling occurs. Cake layer formation on the membrane surface constituted the main fouling mechanism and the incidence of irreversible fouling was so small as to be negligible. The degree of fouling correlated very strongly with membrane permeability. This implies that hydrodynamic conditions are important factors affecting membrane fouling. The fouling contribution of each sludge fraction appeared to depend on particle size, as both permeation drag and back transport velocity are particle size-related functions. Solutes played a significant role in the initiation of cake layer formation, because they were deposited onto the membrane surface and pore wall immediately upon initial filtration, but were dislodged only in small amounts by cross flow. Suspended solids were consistently deposited onto the membrane surface, until flux reached a steady state and colloids exhibited characteristics commensurate with an intermediated state between solutes and suspended solids. Suspended A solids were, in fact, found to be the main contributor to the fouling process. However, the relative contribution of each of the sludge fractions to membrane fouling varied with the permeability of the membrane, and also with the hydrodynamic condition. (c) 2005 Elsevier B.V. All rights reserved.