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WATER QUALITY IMPROVEMENTS DURING RIVERBANK FILTRATION AT THREE SITES IN THE MIDWESTERN US
Citation:
Weiss, W. J., E. Bouwer, W. P. Ball, C. R. O'Melia, T F. Speth*, AND H. Arora. WATER QUALITY IMPROVEMENTS DURING RIVERBANK FILTRATION AT THREE SITES IN THE MIDWESTERN US. Proceedings of the Second International Water Association World Water Congress, Berlin, Germany, 10/15-19/2001.
Description:
A 3-year project is underway to evaluate riverbank filtration systems along three major US rivers. A principal aspects of the study involved monitoring a suite or organic, inorganic, and microbiological water quality parameters, with emphasis on disinfection byproduct formation potential (DBPFP) and related parameters. In a second phase, conventional treatment of river water was simulated in the laboratory to provide comparison with bank-filtered samples. A third phase is underway and employs XAD-8 fractionation to elucidate changes in the character of the organic matter upon bank filtration. For wells 27-61 meters distant from the river, average reductions of dissolved organic carbon ranged from 36-67% and average reductions for precursors of total trihalomethanes and haloacetic acids ranged from 50-77%. In comparison with laboratory treated river water, bank filtation provided higher or comparable reductions. A shift toward a larger fraction of more brominated DBP species was observed in both treated waters. Clostridium and bacteriophage were frequently detected in river samples but rarely in well samples, leading to estiamted log removals on the order of 3.0 for Clostridium and >1.6 for bacteriophage. Giardia and Cryptosporidium were only rarely observed at levels above detection limits in either river or well samples.