Non-Pumped Wells in Backfilled Trenches versus Permeable Reactive Barriers for Containing and Treating Contaminated Groundwater

A flow and mass transport model simulated two low-energy groundwater remediation strategies: 1) a permeable reactive barrier and 2) non-pumped wells with filter cartridges in a backfilled trench. Both structures occupied a linear transect 5 m downgradient of the leading tip of a contaminant plume and perpendicular to the local hydraulic gradient. In each of four simulated homogeneous and heterogeneous settings, models identified the shortest permeable reactive barrier (measured lengthwise, normal to the ambient hydraulic gradient) or locations of the smallest number of non-pumped wells necessary to contain and remove a contaminant plume. Results suggest that non-pumped wells emplaced in trenches backfilled with aquifer material (when allowed from a regulatory perspective) may be a viable alternative to more costly permeable reactive barriers in some settings.