AWWA ACE68691

Wide concern has been raised over the presence of micropollutants, such as pesticides,endocrine disrupting compounds, pharmaceuticals, and personal care products in drinkingwater. Granular activated carbon (GAC) adsorption can be an effective process forremoving a wide array of dissolved micropollutants. However, the role of desorption onthe overall adsorption process is not well understood and may effect the overallperformance. Desorption occurs in filter-adsorbers where backwashing redistributesGAC particles in the adsorber bed. Desorption also occurs after a pulse of pollutant haspassed causing the reversal of the concentration gradient. This study found that thebackwashing effect was much less pronounced than previous research suggested and thatdesorption of pollutants after a pulse had passed was much slower than predicted by themodels. A portion of this behavior may be attributed to a thermodynamic favorability ofadsorption, it is also hypothesized that hindered back-diffusion caused by the presence ofirreversibly adsorbed natural organic matter contributes to the hysteresis. Includes 3 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2008

Number of Pages:

8

File Size:

1 file , 650 KB