Full Description

The traditional method for determining whether a membrane is considered anultrafiltration (UF) or microfiltration (MF) membrane is based upon the molecular weight cutoffof the membrane or the nominal pore size. Microbial removal performance does not currentlyplay a quantitative role in determining whether a membrane is classified as MF or UF. Thisleads to ambiguity in the classification of low-pressure membranes. The overall goal of thisAwwaRF-funded research was to develop a systematic performance testing protocol andspecification for low-pressure membranes with respect to removal of viral and submicronbacterial pathogens with various water qualities and operating conditions. Pilot studies wereconducted at the Atlanta Fulton County Water Treatment Plant, Georgia with a continuousmicrofiltration (CMF) unit (hollow fiber, PVDF membrane) to evaluate its capability to removemicroorganisms under selected water quality and operational conditions. The pilot unit was fedwith dechlorinated finished water, raw water from the Chattahoochee River, and filtered water.The microorganisms tested were MS2 phage, PRD1 phage and Pseudomonas diminuta. Underclean water conditions (using dechlorinated finished water), the removal of PRD1 phage rangedbetween 1.2 and 1.6 log, while negligible removals of MS2 phage were observed. Completeremoval of Pseudomonas diminuta (5 Log) was observed under the same conditions. Short- andlong-term fouling experiments with raw and filtered water showed that cake layer formation andpneumatically-irreversible fouling can induce additional phage removal to a variable extentdepending upon the size of the microorganism, the feed water quality and the decline in specificflux. Includes 12 references, tables, figures.

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Edition: Vol. - No. Published: 06/15/2003 Number of Pages: 19File Size: 1 file , 670 KB