MODELING OF NATURAL ORGANIC-MATTER TRANSPORT PROCESSES IN GROUNDWATER

A forced-gradient tracer test was conducted at the Georgetown site to study the transport of natural organic matter (NOM) in groundwater. In particular, the goal of this experiment was to investigate the intera ctions between NOM and the aquifer matrix. A detailed three-dimensiona l characterization of the hydrologic conductivity heterogeneity of the site was obtained using slug tests. The transport of a conservative t racer (chloride) was successfully reproduced using these conductivity data. Despite the good simulation of the flow field, NOM breakthrough curves could not be reproduced using a two-site sorption model with sp atially constant parameters. Preliminary results suggest that differen t mechanisms for the adsorption/desorption processes, as well as their spatial variability, may significantly affect the transport and fate of NOM.