Behavior of major and trace elements in a transient surface water/groundwater system following removal of a long-term wastewater treatment facility source.

In many aquatic environments, municipal wastewater treatment facility (WWTF) effluent discharges influence local hydrologic and chemical connectivity between the surface-water and adjacent alluvial shallow-groundwater systems. Fourmile Creek located in Polk County, Iowa received effluent from the Ankeny WWTF for nearly forty years before it was shut down in November 2013. The decommissioning of the municipal WWTF provided a unique opportunity to characterize the recovery from impacts of treated wastewater discharge on water quality at the surface-water/groundwater interface in a shallow, unconfined alluvial aquifer.