摘要
膜污染是限制膜生物反应器(MBR)广泛应用的主要技术瓶颈之一。今通过研究浸没式MBR中溶解性微生物产物(SMP)及其聚集尺度的演变过程,深入解析SMP对膜污染的作用机理。在单膜丝微滤膜分离实验中考察了MBR污泥特性,包括污泥浓度(MLSS)、胞外聚合物(EPS)和SMP及其有机物组分等对膜污染的影响行为。结果表明,MLSS、EPS和SMP浓度与膜污染发展速率(ΔTMP/Δm)均呈正向相关。膜污染发展速率与MBR中活性污泥混合液(AS)中SMP的相关性(rp=0.126)远小于滤饼层污泥混合液(CS)中的SMP(rp=0.871)。SMP中的蛋白类和多糖类物质是造成膜污染的主要成分。MBR中的SMP在膜截留作用下出现显著的聚集结构变化和聚集尺度增加的现象。通过荧光光谱指纹图谱(EEMs)对比和共聚焦荧光显微镜(CLSM)观测发现:相比MBR出水,AS中的SMP存在显著的类蛋白峰和较高荧光强度的类腐殖酸峰,CS中的SMP聚集尺度显著增大,粒度可达100μm以上,并具有较强的疏水性能和黏度,可加快膜表面滤饼层(或凝胶层)的生成进程,导致膜污染的发生。通过对膜表面滤饼层结构和组分的分析,当AS中的SMP浓度低于0.4 mg TOC(g SS)1时,膜表面较易形成污泥滤饼污染层,反之,则倾向于生成凝胶污染层。因此,SMP及其聚集态物质是造成膜污染的主要因素,应在膜污染控制方面予以重要关注。
Membrane fouling is the main bottleneck of the membrane bioreactor （MBR） and its widespread application. In this paper, a lab-scale submerged MBR treating synthesis wastewater was operated to examine the affecting mechanisms and correlation of soluble microbial products （SMP） with membrane fouling. A single-fiber microfiltration set-up was fabricated and applied to evaluate the importance of sludge properties of different sludges, including MLSS, EPS, SMP and their organic components, to the fouling evolution rate. It was revealed that MLSS, EPS and SMP all show positive correlation with the fouling rate （ATMP/Am）. However, the importance of SMP separated from MBR activated sludge （AS） to fouling rate （rp= 0.126） is rather lower than that of SMP in MBR cake sludge （CS） （rp=0.871）. The protein and polysaccharide in CS-SMP, other than humic-like substances, were proved to be the major substances affecting fouling layer formation. Both the examination by fluorescence excitation emission matrix （EEM） and the observation under confocal laser scanning microscopy （CLSM） display that the SMP have to transform in the term of surface properties and size distribution with the development of membrane filtration. The AS-SMP has obvious protein-peak comparedwith MBR effluent, which implies that the protein is preferentially intercepted by membrane compared with other organic components. Whilst, after the membrane interception, the SMP in CS has a size as large as 100 μm, which would facilitate the cake layer formation and hence is determinative for the fouling evolution. A comprehensive observation of fouled membrane surface with CLSM also demonstrates that there are two types of fouling layer on the membrane surface, i.e. cake-dominant and gel-dominant fouling layer, both of which are highly depend on the content of AS-SMP in SMBR. It was noted that the SMP in SMBR and cake sludge is the major foulant. The present work is valuable for understanding of the membrane fouling mechanisms and al
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2013年第6期1064-1071,共8页
Journal of Chemical Engineering of Chinese Universities
基金
广东省自然科学基金博士启动项目(S2012040006350)
中国博士后科学基金资助项目(2012M510975)
关键词
浸没式膜生物反应器
膜污染
溶解性微生物产物
污水处理
submerged membrane bioreactor （SMBR）
membrane fouling
soluble microbial products （SMP）
wastewater treatment
