【作者】 李艳松；

【导师】 张捍民；

【作者基本信息】 大连理工大学 ， 环境工程， 2006， 硕士

【摘要】 膜生物反应器（Membrane Bioreactor,MBR）是将膜过滤技术应用于污水处理的一项新兴技术,然而膜污染制约了其广泛应用。国内外学者对膜污染进行了广泛的研究,取得了一些成果。当前研究主要侧重于对膜通量和过膜压力变化的宏观考察以及凝胶层微观结构上的定性比较,而缺乏对膜污染的微观机理研究以及凝胶层微观结构的定量描述。本文结合国家自然科学基金课题,针对现今应用最广泛的疏水性聚乙烯中空纤维膜进行膜污染因子识别研究,考察了活性污泥特性和污泥浓度的对膜污染的影响,并利用分形理论和多孔介质流动力学从微观角度对造成最主要膜污染的凝胶层的渗透能力进行分析,建立起膜污染因子与凝胶层分形渗透率之间的关系模型,得到了如下结论: （1） 胞外聚合物（Extracellular Polymeric Substances,EPS）作为包裹在菌胶团外层的高分子有机物质,对活性污泥表面性质有很大的影响。随着蛋白质/多糖比例的增大,污泥表面的Zeta电位绝对值|δ|减小,而相对疏水性R_H都会随之增大。实验发现污泥表面性质与膜污染之间关系:相对疏水性R_H与膜污染阻力呈正相关关系,而Zeta电位绝对值|δ|对膜污染阻力有负作用,并建立起污泥表面性质与膜污染阻力之间的数学模型:R_f=23.7×R_H-0.26|δ|-6.08; （2） 凝胶层阻力R_c占膜污染总阻力R_t的50-90%,是膜污染最主要成分,有必要对其进行结构分析; （3） 结合多孔介质流动力学和分形理论,引进相对渗透率的概念,推导出分形多孔介质的渗透模型,提出多孔介质的分形渗透率公式:K₁=π/8s·d_f/（4-d_f）·λ_max⁴; （4） 利用扫描电镜观察和图像分析仪获取凝胶层表面孔隙数据,发现凝胶层表面孔隙分布无序不均,具有很好的分形特征;采用分形模型得到的理论渗透率与通过阻力连续模型计算得到的实际渗透率之间存在一定的相关性。提出了分形渗透模型的修正公式K=1.3×π/8s·d_f/（4-d_f）·λ_max⁴; （5） 建立了膜污染因子之一活性污泥浓度MLSS与分形渗透率K之间的关系模型:K=0.849e^-9×10-5MLSS。更多还原

【Abstract】 Membrane Bioreactor, as a new technology for wastewater treatment using membrane filter technology, is under restriction in broad application for high run fee because of membrane fouling. Up to now, lots of researches were made on the membrane fouling and great of developments have been reached. However, former researches focused on the change of membrane flux and trans-membrane pressure, or the qualitative compare of micro structure of cake layer, which lacking for the micro mechanism of membrane fouling and quantitative description of cake layer. In this paper, the hydrophobic polythene hollow fibre membrane was adopted to investigate influence of the membrane fouling factors including concentration and property of active sludge on the membrane fouling, and Fractal theory was used to analyze the micro permeability of cake layer, and the relationship model between membrane fouling factor and Fractal permeability was established.The main research conclusions are summarized as follows:（1） Extracellular Polymeric Substances, as organic matters wrapping around the zoogloea, affected the surface property greatly. With the increasing of the ratio of protein and amylase, the relative hydrophobic was increasing and absolute value of Zeta potential |δ| was inopposition. It was found that the with the change of the relative hydrophobic and Zeta potential of sludge surface, the assemble state between the sludge particle was change which result in the difference of membrane fouling resistance as: R_f = 23.7×R_H - 0.26||δ|- 6.08;（2） The cake layer resistance R_c made up 50%-90% of the total fouling resistance R_t, and required a micro structure analysis;（3） The permeability theory of porous media and fractal theory were combined to deduce apermeability model of porous fractal media as the formula: K₁=[π/8s·d_f/（4-d_f）·λ_max⁴]（4） With the help of Scan Electronic Microscopy and date of Image Analysis System, it was found that the pore distribution of cake layer surface was out-of-order and possess Fractal character. However, the theory permeability obtained from the fractal model was relative with the actual permeability of cake layer, and a special Fractal permeability model for the cakelayer was put forwards as:（5） As a membrane fouling factor, the concentration of active sludge affected the Fractal permeability as: K = 0M9e’9xl°5MLSS ■更多还原