An extraction system was installed to recover contaminated groundwater from both the shallow and deep aquifers. Extracted groundwater is pumped to a treatment plant located on the southern edge of the Henfield property. The treatment plant includes a holding tank that collects groundwater pumped from the extraction system. An air stripper removes VOCs. A two stage activated carbon column provides for additional removal of organics from the air stripper effluent.
Treated water is discharged by gravity to an underground storm water drain.
An additional shallow aquifer intercepting trench was installed along with two monitoring wells in order to address a VOC plume that was extending beyond the original area of concern. A final inspection was held on August 18, 1989. A punch list was developed, and final modifications were requested. The Remedial Action Report was approved by U.S. EPA on April 24, 1991. U.S. EPA completed a Five-Year Review on January 17, 1996.