Effect of dissolved organic matter and bacteria on contaminant transport in riverbank filtration Song-Bae Kim a, * , M. Yavuz Corapcioglu b , Dong-Ju Kim a a Department of Earth and Environmental Sciences, Korea University, Seoul 136-701, South Korea b Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA Received 6 May 2002; received in revised form 17 February 2003; accepted 26 February 2003 Abstract A mathematical model for the transport of hydrophobic organic contaminants in an aquifer under simplistic riverbank filtration conditions is developed. The model considers a situation where contaminants are present together with dissolved organic matter (DOM) and bacteria. The aquifer is conceptualized as a four-phase system: two mobile colloidal phases, an aqueous phase, and a stationary solid phase. An equilibrium approach is used to describe the interactions of contaminants with DOM, bacteria, and solid matrix. The model is composed of bacterial transport equation and contaminant transport equation. Numerical simulations are performed to examine the contaminant transport behavior in the presence of DOM and bacteria. The simulation results illustrate that contaminant transport is enhanced markedly in the presence of DOM and bacteria, and the impact of DOM on contaminant mobility is greater than that of bacteria under examined conditions. Sensitivity analysis demonstrates that the model is sensitive to changes of three lumped parameters: K 1 + (total affinity of stationary solid phase to contaminants), K 2 + (total affinity of DOM to contaminants), and K 3 + (total affinity of bacteria to contaminants). In a situation where contaminants exist simultaneously with DOM and bacteria, contaminant transport is mainly affected by a ratio of K 1 + /K 2 + /K 3 + , which can vary with changes of equilibrium distribution coefficient of contaminants and/or colloidal concentrations. In riverbank filtration, the influence of DOM and bacteria on the transport behavior of contaminants should be accounted to accurately predict the contaminant mobility. D 2003 Elsevier Science B.V. All rights reserved. Keywords: Riverbank filtration; Hydrophobic organic contaminant; Dissolved organic matters; Bacteria; Colloid- facilitated transport 0169-7722/03/$ - see front matter D 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0169-7722(03)00025-1 * Corresponding author. Tel.: +82-2-3290-3642. E-mail addresses: songbaekim@hotmail.com (S.-B. Kim), yavuz@neo.tamu.edu (M. Yavuz Corapcioglu). www.elsevier.com/locate/jconhyd Journal of Contaminant Hydrology 66 (2003) 1 – 23