Correlation between membrane fouling and characteristics of sludge in a membrane bioreactor treating wastewater from supermarket
膜-生物反应器处理超市废水中污泥性质与膜污染关系分析

On the basis of a full-scale submerged membrane bioreactor (MBR) for the treatment of wastewater from supermarket, the variation of extracellular polymer substances (EPS), soluble microbial products (SMPs), soluble chemical oxygen demand (SCOD) and mixed liquor suspended solid (MLSS) in the mixed liquor were investigated. It was found that the accumulation of EPS which was triggered by several reasons had negative effects on the settleability of sludge. Moreover, the variation of SMPs had good relationships with the variation of EPS hydrolyzed by microorganisms. The statistical analysis software (SPSS) was introduced to specify the correlation between membrane fouling and the characteristics of sludge. It showed that the correlation between each two different characteristics of sludge including EPS, SMPs, SCOD, MLSS was good. Meanwhile, the result indicated that SMPs had the most important impact on the membrane fouling, followed by EPS and SCOD, while MLSS had no significant correlation with the membrane fouling. However, according to the partial correlation analysis, there were no significant correlations between characteristics in the mixed liquor and membrane fouling, which implied that the factors could not affect membrane fouling independently. Therefore, it was demonstrated that membrane fouling was a complex process which was caused by the combined effects of several different characteristics.