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Soil Vapor Extraction Test Report for SWMU B-3
Section 1 - Introduction
This report summarizes soil vapor extraction (SVE) treatability study activities for remediation of soil contaminants at the solid waste management unit (SWMU) Burn Area 3 (SWMU B-3) located at Camp Stanley Storage Activity (CSSA) in
In December 1996, an addendum to the original pilot test work plan was prepared. The purpose of the addendum was to expand the existing pilot test system and perform additional testing to further evaluate the site and determine optimal operating parameters for long-term operational system requirements for VOC site remediation. The primary goals of this expanded treatability study were to provide a more accurate characterization of the amount of contaminants located in the SWMU B-3 trench, to determine the potential long-term effectiveness of SVE for removing VOC contamination, and to make recommendations regarding extended testing and future implementation of SVE at SWMU B-3. Although VOC contamination has been encountered in the native limestone surrounding the SWMU B-3 trenches, the primary focus of this study was to maximize VOC removal from contaminated soils in the trench so that continued VOC migration from the trenches into underlying and surrounding fractures is minimized. The ultimate goals of this program are to protect the local groundwater and to achieve site closure by reducing contaminant levels at SWMU B-3 below TNRCC regulatory criteria.
This report describes the results of the additional data collection activities that were performed on the expanded system to accomplish these goals. The main site activities began with system expansion in December 1996 and were completed in May 1997 with the final multiple configuration test and procurement of an automated drain for the blower system�s moisture separator. Additional soil sampling was conducted in April 2000 and has been incorporated into this final report.
1.2 - Investigation Objectives and Scope
The primary tasks that were performed as part of the second phase of the SVE treatability study are briefly outlined below.
The January 1997 system check was performed to evaluate system performance, collect initial soil gas chemistry data for a hydrocarbon recovery test, and determine VOC removal rates after numerous weeks of continuous air extraction.
Twelve soil borings were drilled and sampled, and vapor extraction wells (VEWs) were installed in each boring. These VEWs were connected to the site blower for eventual use in the treatability test activities. One soil sample was collected from each boring and analyzed for VOCs, metals, and miscellaneous physical parameters.
Five confirmation soil samples were collected to assess the removal of VOCs that has occurred during the past 10 months of SVE operations. These samples were collected from soils adjacent to the locations initially sampled during installation activities in February 1996, prior to initiating any air extraction from the existing system.
A hydrocarbon recovery test was performed after shutting off the extraction blower following the January 1997 system check. Soil gas was monitored at each VEW and vapor monitoring point (VMP) to determine recovery rates of volatile hydrocarbons in soil gas and the approximate time required for soils to return to static conditions. Soil gas was also monitored for oxygen and carbon dioxide to determine if biological activity/biodegradation of organic contaminants in the trench area may be occurring.
Periodic testing of three different extraction configurations and the January 1997 system check of the original pilot test layout was performed to determine the effective radius of influence of each VEW extraction configuration.
An automated solenoid valve was procured for connection to the blower system to automate the moisture separator drain.
Re-sampling of soils was performed in April 2000 due to laboratory quality control concerns associated with the original sampling event.
This report is organized in six sections including this introduction. Section 2 provides a brief description of the site and a summary of the previous studies, including the 1996 pilot test, at the site prior to the performance of the expanded treatability study. Section 3 describes the methods and protocols employed to perform the expanded treatability study. Procedures for additional site characterization sampling and construction of the expanded system are also discussed in this section. Results and data evaluation from the expanded study are detailed in Section 4. Section 5 discusses the general conclusions and significant findings of the study, and provides recommendations for future operation and monitoring of the treatment system. References are included in Section 6. Three appendices are attached to this report and include the chemical data informal technical information report (ITIR) (Appendix A), lithologic boring logs (Appendix B), and field data reporting sheets, field data compilation and calculation tables, and field notes (Appendix C).