AWWA MTC57544

Extra-cellular polysaccharides (EPS), soluble microbial products (SMPs), and bacterial cellswere isolated to observe their influence on the flux decline of nanofiltration (NF) systems whichwere challenged with these constituents raised on recalcitrant and readily degradable carbonsources (natural organic matter (NOM), SMPs and acetate). A resistance-in-series model,which related flux decline with membrane-associated polysaccharides was compiled andvalidated. Biofouling tests were conducted using bench-scale, flat-sheet membrane modulesoperated at 95 psi (6.7x105 Pa), pH = 7, and 21C. Increased membrane flux-decline wasassociated with an increase in surface EPS content where between 30-80% of the normalizedflux decline corresponded to membrane-associated EPS content between 5.1 and 50 ug/cm2,respectively. During all tests performed with NOM and acetate, culturable biofilm cell densitiesshowed no statistically significant difference (0.1x108 to 5x108 CFU/cm2) and were independentof EPS concentration. Results from resistance-in-series models suggest that flux decline wasrelatively insensitive to bacterial cell numbers and was governed by EPS associated with themembrane surfaces. Includes 30 references, table, figures.

Product Details

Edition:

Vol. - No.

Published:

03/05/2003

Number of Pages:

10

File Size:

1 file , 270 KB