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Final Phytoremediation Treatability Study
Section 1 - Introduction
The former open burn/open detonation (OB/OD) SWMU B-20 is a 33.5-acre field surrounded by wooded areas in the northeastern portion of CSSA. According to a memorandum on file at CSSA, the B-20 area was first used for demolition activities in 1946. The B-20 operations included detonation of conventional explosive ordnance and other ordnance items, static downward firing of one rocket motor nose, disposal of scrap metal from detonation activities, and disposal of small arms ammunition. Based on the nature of its operation, the B-20 site is considered a thermal treatment unit by state regulators. As a hazardous waste treatment unit, the B-20 site is regulated under both federal and state regulations. The U.S. Environmental Protection Agency, Region VI, Resource Conservation and Recovery Act (RCRA) Enforcement, Texas Section, issued a Compliance Order to CSSA on June 30, 1993. This order required CSSA to immediately cease operations of the unit and prepare a closure plan in accordance with applicable regulations. After the closure plan was prepared and approved, a Remedial Investigation (RI) was conducted. The objectives of the RI were to assess the effect of past waste disposal actions on the environment and to recommend a standard to be applied for site closure. The RI also included several phases of unexploded ordnance (UXO) removal.
The Remedial Investigation Report for B-20 Former Open Burn/Open Detonation Area (Parsons ES, 1995) presented several recommendations for additional work at the B-20 site to prepare it for future closure. Metals levels in surface soils over a large area at the site (approximately 10 acres) were found to exceed background concentrations. The RI report recommended that treatability studies be conducted to determine the most technically appropriate and cost-effective remediation technology for the site.
One of the remediation methods chosen for a treatability study was phytoremediation, the use of plants and plant processes to remove or degrade hazardous materials present in the soil. In order to assess the ability of phytoremediation to remove contaminants from SWMU B-20 soils, a benchscale study was subcontracted to Phytotech, Inc. (Phytotech) of Monmouth Junction, New Jersey. During this study, plants considered to be hyperaccumulators of contaminants present at B-20 were grown in B-20 soils in a controlled environment at the Phytotech greenhouse. EdenSpace purchased the technology rights of the phytoremediation technique from Phytotech shortly after the benchscale study was completed. EdenSpace prepared the final version of the benchscale report for phytoextraction of lead from SWMU B-20 soils. The analyses performed, methodologies, and results from this study form the basis of this report.
This report is prepared by Parsons Engineering Science (Parsons ES) under contract to the U.S. Air Force Air Mobility Command (AMC) Contract F11623-94-D0024, delivery order RL33.