Laboratory test plan in-well vapor stripping system

Abstract

This test plan describes the activities that will be conducted as a part of the laboratory testing of a full-scale mockup of the Stanford in-well vapor stripping system. These tests will be conducted to delineate design parameters for the in-well vapor stripping unit and to identify and quantify variables that are sensitive to the dynamic hydraulic effects induced by operation of the system. No radioactive materials are involved in this test. In-well vapor stripping has been used successfully as an alternative to conventional pump-and-treat technology for remediation of volatile organic compound (VOC) contaminated groundwater in Europe and more recently in the United States. In-well vapor stripping permits in situ remediation of VOC-contaminated groundwater by combining an in-well vapor stripping system with a treatment well is used to extract and discharge groundwater simultaneously, resulting in the establishment of a vertical circulation groundwater flow cell in the aquifer. Groundwater extracted from the aquifer via the lower screened interval is treated for VOCs by in-well vapor stripping within the treatment well. This stripping causes aqueous phase VOCs to partition preferentially into a vapor phase. Treated groundwater is discharged back to the aquifer via the upper screened interval of the treatment well, while the vapor phase VOCs are simultaneously removed from the well bore and contained at the surface with a vacuum extraction system. Groundwater entrained into the vertical circulation flow cell becomes sequentially cleaned of VOC contamination in an efficient manner without the need for surface treatment and handling of contaminated groundwater. An added benefit of in-well vapor stripping is the ability to perform vadose zone vapor extraction concurrently with groundwater remediation. This uses the vacuum extraction capabilities of the in-well vapor stripping configured with the upper screened interval placed into the vadose zone above the water table.