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I. PROJECT DESCRIPTIO <br /> The objective of this project, as specified in contract number <br /> DACA87-89-C-0088 , is to design, install, operate and evaluate an <br /> interim groundwater treatment system (IGTS) at Defense Depot <br /> Tracy, California (DDTC) . This project is an effort under <br /> Department of Defense (DOD) Defense Environmental Restoration <br /> Account (DERA) . The groundwater treatment system shall control <br /> the migration of the highest concentration of trichloroethene <br /> (TCE) and tetrachloroethene (PCE) plume at the northwestern <br /> boundary of DDTC. <br /> The IGTS has been designed to withdraw groundwater from the <br /> aquifer, to treat the contaminated water in an Air Stripping <br /> Tower (AST) and to inject the treated groundwater back into the <br /> aquifer. Phase I of the IGTS shall includes six extraction wells <br /> to remove the contaminated groundwater and three injection wells <br /> to replace the treated groundwater into the aquifer. The system <br /> may be expanded to as many as seventeen extraction and six <br /> injection wells at various locations, after successful operation <br /> and evaluation of the Phase I of the IGT system. Ten monitoring <br /> wells will be utilized in Phase I of operation to collect data <br /> for the evaluation of the IGT system. <br /> Evaluation of the system will include data collection during <br /> various stages of operation from several well locations and from <br /> the AST inlet and outlet. The data will be utilized to prepare <br /> and establish a computerized, numerical,, three-dimensional <br /> groundwater model to evaluate the effectiveness of the Interim <br /> Remedial Measure (IRM) and to predict appropriate changes to the <br /> IRM that will lead to increased efficiency in the future. <br /> The primary contaminants identified at the northern boundary of <br /> the DDTC are TCE, and PCE. Low levels of toluene and chloroform <br /> have also been detected in the northern portion of the DDTC . <br /> Trans-1, 2-dichloroethene (DCE) has also been detected in minor <br /> amounts. DCE is considered a biodegradative product of TCE. The <br /> data indicate that PCE ranges from below detection limits to as <br /> high as 430 ppb and TCE ranges from below detection limits to 560 <br /> ppb. <br /> TCE is incompatible with strong bases, oxidizing agents, reducing <br /> agents , aluminum, magnesium and may decompose on exposure to <br /> light . The hazardous decomposition by products are hydrogen <br /> chloride gas and phosgene gas. Hazardous polymerization is not <br /> known to occur. (Refer to TCE's Material Safety Data Sheet (MSDS) <br /> in Appendix D) . <br /> J. <br /> 1 <br />