Passive wetland system designed as a long-term solution to treat legacy groundwater contaminants, including petroleum hydrocarbons, metals and chlorinated solvents. No electricity is used other than to pump groundwater from the recovery wells to the treatment wetlands.
The treatment system consists of a cascade aerator, sedimentation pond, parallel surface flow wetlands, parallel vertical flow oxic limestone drains, and sand drying beds for iron precipitate dewatering. It removes over 99% of aniline and nitrobenzene from the groundwater, without the use of added chemicals. The design incorporates a trails path, restoration of the adjacent river swale, and a 20-acre site plan using entirely native elements (tress, shrubs, wildflowers, grasses and wetland plants).