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An AwwaRF Project, Optimization of Membrane Treatment for Direct and Clarified WaterFiltration, has been studying the effect of pretreatment chemicals on membrane filtrationperformance. The primary objective of this research is to develop a unified understanding of theinteraction between water quality, pretreatment chemicals, and membrane materials, and toevaluate the difference between membrane performance when studied at the bench and pilotscale. One component of the research has been to evaluate the fouling ofmembranes by various constituents in the water sources. The focus of this research wasto describe experiments in which water was fractionated by microfiltration and ultrafiltrationthrough membranes with various pore sizes, after which the fouling potential of the prefilteredwater was determined.Previous projects have tried to explain fouling mechanisms of ultrafiltration (UF) andmicrofiltration (MF) membranes with artificially prepared water and separating out fulvic acids,humic acids, and humic substances from natural source waters. These experiments have tried toestablish a relationship between artificial water fouling and natural water fouling. Fractionationanalysis with artificial water and natural source water with 100,000 Daltons (Da) and 0.16 mdid not show consistency between various sources of natural organic matter (NOM) (Yuan and Zydney, 1999, 2000). NOM is an important factor in membrane filtration and is considered one ofthe most significant foulants in natural water. NOM affects disinfection byproduct formation,color, taste and odor, hardness, iron, manganese, arsenic, and other organic and inorganiccompounds. UF and MF membranes initially were used in situations with high quality waterwith low fouling tendency, but the membrane technology is now being used more extensively forchallenging waters that can foul the membrane extensively and shorten membrane life.Challenging waters need pretreatment for enhancing the flux, so various coagulants wereevaluated for flux improvement. This project is an effort to quantify foulants based on sizedistribution and to evaluate the effect of pretreatment on the size distribution of foulants. Includes 5 references, tables, figures.

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Edition: Vol. - No. Published: 03/01/2005 Number of Pages: 11File Size: 1 file , 510 KB