A former zinc smelter operating from 1916 to 1974 released zinc and cadmium sulfate solutions to the surficial alluvial aquifer soil and groundwater. The former facility was located immediately adjacent to and hydraulically upgradient of a small town in Oklahoma. We were asked to design a remedial action for a persistent groundwater plume underlying the town and infiltrating the town sewer systems.
We conducted focused field investigations to fill critical data gaps, which allowed us to develop a detailed conceptual site model and a groundwater model to quantitatively understand the hydrogeology and water balance of the alluvial aquifer. We then designed a network of groundwater extraction wells to capture the groundwater plume for ex situ chemical treatment and eliminate plume infiltration to the sewer systems.
After nearly a decade of groundwater treatment in operation, the remedy continues to be highly effective in containing the groundwater plume and reducing metals concentrations in extracted groundwater prior to discharge by more than 99 percent.