采用统计分析方法研究了16种不同性质活性污泥混合液对膜生物反应器膜污染的影响机理。结果表明，胞外聚合物 （extracellular polymeric substances, EPS）、溶解性有机物（soluble microbial products, SMP）、上清液胶体颗粒（suspended solids in supernatant, SSs）、污泥混合液粘度（μ）、相对疏水性（relative hydropho bicity, RH）、Zeta 电位（Zeta potential） 均对膜生物反应器膜渗透性能有显著的影响作用，其与膜污染阻力的皮尔逊相关系数rp分别为：01898、01712、01810、01691、01837、-01881；同时发现，胞外聚合物是影响活性污泥中溶解性有机物含量（rp=01682）、污泥粘度大小（rp=01633）、上清液胶体颗粒含量（rp=01783）、Zeta 电位（rp=-01953） 及相对疏水性大小（rp=01877） 的主要因素；在活性污泥性质中胞外聚合物是影响膜污染的根本原因，是膜生物反应器膜污染的重要影响因素.

对序批式运行方式强化膜生物反应器脱氮除磷效果进行了研究。在试验过程中逐渐降低进水CODPTN值，提高总氮负荷，比较序批式膜生物反应器和传统膜生物反应器的脱氮除磷性能与膜污染状况。试验结果表明，进水CODPTN降至318～813，总氮负荷提高至0122kg·m-3·d-1时，传统膜生物反应器无法脱氮，而序批式膜生物反应器通过改变周期、提高交换比等方式，TN和氨氮去除率分别保持在6716%和9311%.序批式的运行方式还可以减轻膜污染.

This paper examines the influence of activated sludge properties such as the mixed liquid of suspended solids (MLSS) concentration, sludge particle size distribution (PSD), extracellular polymeric substances (EPS), soluble microbial products (SMP), suspended solids in supernatant (SSs), dynamic viscosity (µ), relative hydrophobicity (RH), and zeta potential on membrane fouling. ctivated sludge samples from different full-scale and lab-scale membrane bioreactor processes were used to study their impacts on membrane fouling. The influence of activated sludge properties on membrane permeation was identified with statistical methods. The results showed that MLSS concentration had an exponential relationship with membrane fouling resistance. The sludge particle size (rp=−0.730) was correlated inversely to the membrane fouling resistance significantly. The total EPS (rp=0.898) and protein (rp=0.810) had strong positive effect on membrane fouling resistance, but carbohydrate (rp=0.626) had a moderate correlation with membrane fouling resistance due to its low amounts. SMP (rp=0.757), SSs (rp=0.810), dynamic viscosity (rp=0.691), RH (rp=0.837), and zeta potential (rp=−0.881) also had significant influence on membrane permeability. However, protein (rp=0.936), SMP (rp=0.725), SSs (rp=0.783), dynamic viscosity (rp=0.633), RH (rp=0.877), and zeta potential (rp=−0.953) mainly resulted from the change of EPS concentration. These results confirm that MLSS concentration, PSD and EPS were the predominant factors affecting membrane fouling during membrane filtration of sludge suspension. The membrane fouling resistance can be predicted using a simple model based on MLSS concentration, PSD and EPS.

Membrane bioreactor (MBR) is an important solid–liquid separation technology employed widely in the wastewater treatment. However, membrane permeability decline rapidly due to membrane fouling, which limited the application of MBR. In order to obtain understanding of the complex membrane fouling mechanisms, analysis of the effect of the microstructure on the cake permeability is necessary. In this regard, study of the distribution and porosity of the cake is very necessary. The pore distribution is strongly influenced by cake compressibility but information on how to describe this effect is very limited. In this paper, fractal theory was used to gain knowledge of cake icrostructure and its correlation to macroscopic cake properties. Scanning electron microscopy (SEM) and image analysis were utilized to estimate pore size and pore size distributions. The two-dimensional fractal dimension was determined. The results show that the cake layer had a good fractal characteristic, and the fractal dimension (Ds) was linearly correlated with porosity (R2=0.929). The fractal dimension had some relation with cake resistance and cake specific resistance. It indicates that fractal dimension provides an approach for quantification of cake structure and cake permeability.

Cake layer formation on the membrane surface has been a major challenge in the operation of membrane bioreactors (MBRs). In this study, the cake layer formation mechanism in an MBR used for synthetic wastewater treatment was investigated. The major components of cake layer were systematically examined by particle size analyzer (PSA), scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), X-ray fluorescence (XRF), energydiffusive X-ray analyzer (EDX), and Fourier transform infrared (FTIR) spectroscopy. The results indicate that the small particles in sludge suspension had a strong deposit tendency on the membrane surface. The SEM and CLSM analysis exhibited that bacterial clusters and polysaccharides were significant contributors to membrane fouling. The main components of biopolymers were identified as proteins and polysaccharide materials by the FTIR. The examination by EDX and XRF demonstrated that Mg, Al, Ca, Si, and Fe were the major inorganic elements in fouling cake. Furthermore, the results suggest that bridging between deposited biopolymers and inorganic compounds could enhance the compactness of fouling layer. During the operation of MBRs, the biopolymers and inorganic elements in the bioreactor should be controlled to minimize membrane fouling.