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RIVERBANK FILTRATION AS A PRETREATMENT FOR NANOFILTRATION MEMBRANES
Citation:
Speth*, T F., T. Merkel, C J. Parrett*, A M. Grandin*, A. M. Gusses, AND R. S. Summers. RIVERBANK FILTRATION AS A PRETREATMENT FOR NANOFILTRATION MEMBRANES. Presented at Extended Abstract and Poster Presentation at the International Riverbank Filtration Conference, Louisville, KY, November 4-6, 1999.
Description:
The loss of membrane efficiency due to fouling is one of the main impediments to the development of membrane processes for use in drinking water treatment. Surface waters, in general, have a greater proclivity towards fouling as compared to groundwaters. Riverbank filtration changes a surface water into a water with characteristics close to that of a groundwater. Therefore, riverbank filtration should be an effective pretreatment for nanofiltration or reverse osmosis membrane technologies. The goal of this work was to evaluate riverbank filtration versus conventional treatment as river-water pretreatments for nanofiltration membranes.
The conventionally-pretreated membranes had much shorter calculated cleaning frequencies as compared to the riverbank-prefiltered membranes. The shorter calculated cleaning frequencies demonstrated that the conventionally-pretreated membranes had higher fouling rates. As a further indication that the riverbank-prefiltered membranes experienced less fouling than the conventionally-pretreated membranes, the Southwestern Ohio and Louisville riverbank-prefiltered systems lost 12 and 24 percent of their initial fluxes over 62 days of operation, respectively, whereas the conventionally-pretreated systems lost between 36 and 50 percent of their initial fluxes over the same length of time. These results demonstrate that riverbank filtration is a superior nanofiltration pretreatment than conventional treatment.