You are here:
RIVERBANK FILTRATION: EFFECT OF GROUND PASSAGE ON NOM CHARACTER
Citation:
Weiss, W. J., E. Bouwer, W. P. Ball, C. R. O'Melia, R. Aboytes, AND T F. Speth*. RIVERBANK FILTRATION: EFFECT OF GROUND PASSAGE ON NOM CHARACTER. AQUA - JOURNAL OF WATER SUPPLY RESEARCH AND TECHNOLOGY. IWA Publishing, London, Uk, 53(2):61-83, (2004).
Impact/Purpose:
information
Description:
Research was conducted to explore the effect of underground travel on the character of the natural organic matter (NOM) originating from the river water source during riverbank filtration (RBF) at three Midwestern US drinking water utilities. Measurements of biodegradable dissolved organic carbon (BDOC) and assimilable organic carbon (AOC) show significant reduction (50-90%) in the biodegradable portion of NOM at two of the sites. Specific UV-absorbance (SUVA) values indicate preferential reduction (26% reduction in SUVA) in UV-absorbing NOM at one of the sites. XAD-8 characterization was carried out on the river and well waters to investigate possible changes in the character of the NOM. The distribution of dissolved organic carbon (DOC) over the XAD-89 adsorbing ("hydrophobic") and non-adsorbing ("hydrophilic") fractions was similar between the river and well waters (50-60% hydrophilic and 40-50% hydrophobic), indicating no significant preferential removal of either fraction upon ground passage. Disinfection by product (DBP) formation testing was performed on the various fractions, keeping the ratio of chlorine:DOC:bromide constant. Trihalomethane (THM) and haloacetic acid (HAA) concentrations in the chlorinated waters showed no preferential removal of DBP precursors among the hydrophobic and hydrophilic fractions. While the overall concentrations of DBP precursors are effectively reduced during bank filtration, the reductions appear to be largely the result of the reduction in NOM concentration rather than a consistent change in NOM character. In addition, with equal concentations of bromide in the river and well waters during chlorination testing, there does not appear to be any preferential removal of precursor material responsible for the chlorinated or brominated DBP species.
