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SWMU B-23 Closure Report
Section 2 - Closure Activities
SWMU B‑23 is located in the central portion of the North Pasture at CSSA. Based on the RFI sampling results, closure of SWMU B‑23 required excavation and disposal of the waste material present at the site along with confirmation sampling to ensure that all waste and waste residue was removed.
CSSA operations limit accessibility to the North Pasture. Therefore, although excavation of SWMU B‑23 was initiated on December 2, 2003, it was not completed until May 2004. Excavation was conducted by Eagle Construction and Environmental Services, with oversight by a Parsons construction manager. The December and January activities consisted of a limited excavation search for indications of wastes associated with past uses of the site. Soil was excavated from approximately the top two feet of the site in January 2004. These initial excavation activities were focused in areas associated with exceedances from the initial 2000 soil boring sample results. No solid wastes were found during the limited excavation in December, but a small amount of banding material and scrap metal was found when the soil was removed in January. On May 5, 2004 final excavation activities were conducted on the east side of the site. The final excavation consisted of an excavation approximately 15 feet long by 15 feet wide by 6 feet deep in the southeast end of the site, which yielded additional scrap metal. Photographs of the excavation are shown in Figure B23‑9.
A total of 270.44 CY of waste and waste residue were excavated from the site. Disposal of the waste was conducted in May 2004 under waste profile CG‑25591, C‑3. The JATO canisters were disposed along with the soil waste, at the approval of the landfill. Waste manifests are provided in Appendix B, along with a summary of waste characterization results. Toxicity characteristic leaching procedure (TCLP) results from the stockpiled waste indicated the material met non‑hazardous Class 2 criteria, so the waste was disposed of at Covel Gardens Landfill, in San Antonio, Texas. Following closure activities at the site, the site was graded and reseeded. The site restoration activities post‑date the photos below.
2.2 - Confirmation Sampling
Confirmation sampling was performed after excavation activities on February 3 and 17, 2004, and again on May 21, 2004 to verify that all waste residue had been removed. Once the soil was excavated, samples were collected on the sidewalls and on the bottom of the excavated area. Closure confirmation samples include B23‑BOT01, B23‑BOT02, and B23‑SW01 through B23‑SW07, as shown on Figure B23‑8.
Confirmation soil samples were analyzed for barium, copper, nickel, and zinc (SW6010B), and lead (SW7421). The metals sampling suite was determined based on the metals exceedances from the initial 2000 soil boring results, as discussed in Section 1.4.3 of this report. In addition to the metals, several VOCs were included in the analysis, including benzene, dichlorodifluoromethane, ethylbenzene, toluene, m&p‑xylenes, and o‑xylene (SW8260B). Results of the confirmation sampling indicated that metals were below established background levels and VOCs were below the lab RLs for all samples (Table B23‑3). An analytical results summary is presented in Appendix A.
Figure B23‑9 Excavation Photographs
Initial excavation activities conducted on December 2, 2003
Initial excavation activities conducted on December 2, 2003
Initial excavation activities conducted on December 2, 2003