Evaluation of reactive well networks for remediating heterogeneous aquifers.

Alternative configurations of non-pumped wells filled with reactive media were evaluated for removing hypothetical contaminant plumes. All wells were screened across the saturated zone of a simulated unconfined aquifer. Three heterogeneous hydraulic conductivity distributions (cases) were considered. A mass transport model accounting for advection and hydrodynamic dispersion produced an initial contaminant plume for each case. Two reactive well configurations were evaluated for each case. In one configuration, evenly spaced wells occupied a linear transect perpendicular to regional groundwater flow, located downgradient of the contaminant plume. A second configuration involved the same number of wells, but along evenly spaced, nonlinear flow lines originating from the downgradient boundary of the contaminant plume. Mass transport modeling simulated contaminant plumes moving through the aquifer and wells. Results suggest that nonlinear configurations, which take into account local flow variations near the downgradient boundary of a contaminant plume, more efficiently reduce contaminant concentrations and better control offsite migration.