Abstract: The influence of microorganism metabolites，such as soluble microbial products (SMP) and extracellular polymeric substances (EPS)，on membrane fouling was examined during the operation of membrane bioreactor(MBR). The activated sludge samples were taken from a laboratory-scale MBR and used to investigate their filtration resistance in different phases. Results showed that the accumulated SMP and EPS in the MBR have a negative effect on membrane filtration. The SMP，especially those with molecular weight (Mw) of 3—10 kDa，are positively correlated to the pore-blocking resistance. The cake layer formation is the main factor resulting in membrane fouling，and is strongly affacted by the amount of EPS and the SMP with MW＞10 kDa. The major components of EPS in cake layer are proteins，polysaccharides and humic substances as analyzed by Fourier transform infrared spectroscopy (FTIR)，while the dominant components in SMP are polysaccharides and humic substances.

摘要： 针对膜生物反应器（MBR）在运行过程中溶解性微生物代谢产物（SMP）及胞外聚合物（EPS）对膜污染进行研究。实验过程中对MBR内的污泥混合液进行了定期膜阻力监测。结果表明，SMP和EPS对膜过滤阻力有负面的影响。SMP中相对分子质量分布（Mw）在3～10 kDa对膜内部阻力影响显著，SMP中Mw＞10 kDa的大分子有机物及EPS浓度对膜外部阻力影响明显。通过傅里叶转换红外光谱（FTIR）检测膜表面污染物表明，EPS主要由多聚糖、蛋白质和腐殖酸组成，而污染层中的SMP主要是多聚糖和腐殖酸。