Extra-Cellular Polysaccharides, Soluble Microbial Products, and Natural Organic Matter Impact on Nanofiltration Membranes Flux Decline
详细信息 查看全文
- 作者：A. Cristina Fonseca ; R. Scott Summers ; Alan R. Greenberg ; Mark T. Hernandez
- 刊名：Environmental Science & Technology
- 出版年：2007
- 出版时间：April 1, 2007
- 年：2007
- 卷：41
- 期：7
- 页码：2491 - 2497
- 全文大小：127K
- 年卷期：v.41,no.7(April 1, 2007)
- ISSN：1520-5851
文摘
Extra-cellular polysaccharides (EPS), soluble microbiologicalproducts (SMP), dispersed bacterial cells, and a well-characterized natural organic matter (NOM) isolate wereobserved to determine their influence on the flux decline ofmodel nanofiltration membrane systems. Biofouling testswere conducted using bench-scale, flat-sheet membranemodules, fed with particle-free (laboratory) waters and naturalwaters, some of which were augmented with readilybiodegradable organic carbon. The modules were operated6.7 × 105 Pa, and 21 ± 2
C. Membrane flux-decline wasassociated with increases in surface EPS mass: between30 and 80% of normalized flux decline occurred whenmembrane-associated EPS content increased from 5 to 50 
g/cm2. As judged by standard culturing, heterotrophic celldensities recovered from membrane biofilm samples showedno significant correlations with the different carbon sources present in the feedwaters, or flux decline rates. Resultssuggested that, in the absence of microbiological activity,SMP and NOM have intrinsic membrane fouling propertiesat levels that are operationally significant to commercial-scale membrane treatment practices. Results also suggested that SMP may have a biofouling potential significantlygreater than some types of NOM. Trends obtained relatingthese compounds with flux decline were successfullydescribed by expanding existing resistance-in-series models.
C. Membrane flux-decline wasassociated with increases in surface EPS mass: between30 and 80% of normalized flux decline occurred whenmembrane-associated EPS content increased from 5 to 50 g/cm2. As judged by standard culturing, heterotrophic celldensities recovered from membrane biofilm samples showedno significant correlations with the different carbon sources present in the feedwaters, or flux decline rates. Resultssuggested that, in the absence of microbiological activity,SMP and NOM have intrinsic membrane fouling propertiesat levels that are operationally significant to commercial-scale membrane treatment practices. Results also suggested that SMP may have a biofouling potential significantlygreater than some types of NOM. Trends obtained relatingthese compounds with flux decline were successfullydescribed by expanding existing resistance-in-series models.