Accumulation of biopolymer clusters in a submerged membrane bioreactor and its effect on membrane fouling.
Accumulation of biopolymer clusters in a submerged membrane bioreactor and its effect on membrane fouling.
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DOI：
10.1016/j.watres.2007.08.031
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发表时间：
2008-02
期刊：
影响因子：
12.8
通讯作者：
Xiao-mao Wang;Xiao-yan Li
中科院分区：
文献类型：
--
作者：
Xiao-mao Wang;Xiao-yan Li
采用中空纤维膜组件浸没式膜生物反应器（SMBR）研究了不同操作条件下膜污染的变化。结果表明，SMBR内的污泥上清液中的有机物含量始终高于MBR出水。详细的分析揭示了一个池的有机物质，分类为生物聚合物集群（BPC），在SMBR系统中的尺寸大于可溶性微生物产物（SMP）。以总有机碳（TOC）计，MBR污泥混合物中BPC含量为0.7 ~ 18.8mg/L，平均为5.6±3.5mg/L，约为悬浮液中SMP浓度的2倍。在荧光显微镜下和使用DAPI染色，离心后的污泥上清液中的BPC被发现是独立于污泥絮凝体的颗粒有机物质，其粒径分布可达50μm。实验结果表明，BPC是一种重要的污染物，对膜污染有着深远的影响。反应器中的污染速率，如由跨膜压力（TMP）的增加所指示的，在一定程度上与各种条件下污泥悬浮液中的BPC浓度相关。认为BPC是一种特殊形式的有机物，主要由SMP在膜表面沉积的污泥层中吸附和亲和聚集而形成。BPC可以与污泥一起从膜上分离并返回到悬浮液中。BPC在SMBR污泥混合物中的积累会促进膜表面污泥污染层的形成，从而导致严重的污染问题。
A laboratory-scale submerged membrane bioreactor (SMBR) with a hollow-fibre membrane module was used to investigate membrane fouling under various operational conditions. The results showed that the sludge supernatant inside the SMBR had a consistently higher organic content than the MBR effluent. Detailed analysis revealed a pool of organic substances, classified as biopolymer clusters (BPC), in the SMBR system that were larger in size than the soluble microbial products (SMP). The BPC content in the MBR sludge mixture ranged from 0.7 to 18.8mg/L in terms of the total organic carbon (TOC), with an average of 5.6±3.5mg/L, which was about twice the SMP concentration in the suspension. Under a fluorescent microscope and using DAPI staining, the BPC in the sludge supernatant after centrifugation were found to be particulate organic substances that were independent of the sludge flocs and had a size distribution up to 50μm. The findings of the experiment suggest that BPC are an important foulant and have a profound effect on membrane fouling. The fouling rate in the reactor, as indicated by the increase in trans-membrane pressure (TMP), correlates to a certain extent with the BPC concentration in the sludge suspension under various conditions. It is argued that BPC are a special form of organic substances that are formed by the adsorption and affinity clustering of mainly SMP within the sludge layer deposited on the membrane surface. The BPC can be detached with the sludge from the membrane and returned to the suspension. The accumulation of BPC in the SMBR sludge mixture would facilitate the formation of a sludge fouling layer on the membrane surface, thus causing a serious fouling problem.