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NANOFILTRATION FOULANTS FROM A TREATED SURFACE WATER
Citation:
Speth*, T F., R. S. Summers, AND A. M. Gusses. NANOFILTRATION FOULANTS FROM A TREATED SURFACE WATER. 10.1021/es9800434, ENVIRONMENTAL SCIENCE & TECHNOLOGY. ACS, Washington, DC, 32(22):3612-3617, (1998).
Impact/Purpose:
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Description:
The foulant from pilot nanofiltration membrane elements fed conventionally-treated surface water for 15 months was analyzed for organic, inorganic, and biological parameters. The foulant responsible for flux loss was shown to be a film layer 20 to 80 um thick with the greatest depth in the first of three elements in series. Heterotrophic plate counts and phospholipid analyses of the foulant showed a large amount of biomass. Pyrolysis-GC/MS analysis of the foulant also indicated a strong biological signature. The inorganic contribution to the dried foulant was low (less than 15 percent). Neither acid cleaning, alkaline/detergent cleaning, nor hydraulic flushing removed the thickness of the foulant, or changed the pyrolysis-GC/MS characteristics of the foulant. However, the film layer responsible for flux loss could be physically removed very easily. Acid and alkaline/detergent cleaning yielded similar short-term flux recovery, although they were independent of each other. The short-term flux recovery without loss of biofilm thickness suggests a morphological change upon cleaning. Only the alkaline/detergent cleaner inactivated a large percentage of the microbes in the foulant. This suggest that the microbial population became acclimated to the frequent acid cleanings that occurred during the 15-month pilot run.
