Published: 1995
Total Pages: 177
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This work plan was prepared by Parsons Engineering Science, Inc. (Parsons ES), formerly Engineering Science, Inc. (ES), and presents the scope of work required for the collection of data necessary to conduct a treatability study (TS) for the intrinsic remediation of groundwater contaminated with petroleum hydrocarbons and chlorinated aliphatic hydrocarbons (CAHs) at the Priority-One Site Fire Training Area 01 (FT-1) located at Fairchild Air Force Base (AFB), 12 miles west of Spokane, Washington (the Base). The record-of-decision (ROD) for FT-1 specifies the use of air sparging to remediate volatile organic compounds (VOCs) in site groundwater. Therefore, this TS will assess naturally occurring contaminant attenuation processes for groundwater and evaluate how these processes will operate in conjunction with the future air sparging system. This work plan is oriented toward the collection of hydrogeologic data to be used as input into groundwater flow and solute transport models to evaluate intrinsic remediation for restoration of groundwater contaminated with benzene, toluene, ethylbenzene, xylenes (BTEX), and CAHs. As used in this report, the term "intrinsic remediation" refers to a management strategy that relies on natural attenuation mechanisms to remediate contaminants dissolved in groundwater and to control the potential for receptor exposure to site-related contaminants in the subsurface. "Natural attenuation" refers to the actual physical, chemical, and biological processes that facilitate intrinsic remediation. Mechanisms for natural attenuation of BTEX and CAHs include advection, dispersion, dilution from recharge, sorption, volatilization, and biodegradation. Of these processes, biodegradation is the only mechanism working to transform contaminants into innocuous byproducts. Intrinsic bioremediation occurs when indigenous microorganisms work to bring about a reduction in the total mass of contamination in the subsurface without the addition of nutrientc.