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1.0 INTRODUCTION In 2003, a Soil Vapor Extraction and Treatment System (SVETS) and an Air Sparging System (AS) will be installed at the State of California,Department of Transportation (Caltrans),Stockton Yard Maintenance Facility (Facility)located at 1604 South B Street, Stockton,.Califomia. This document is the SVETS and AS Performance Monitoring Plan (PMP)manual. It will be updated periodically to account for changes in system design and operation. 1.1 Purpose The purpose of the SVETS is to extract and treat soil vapor at'the Facility that has been impacted with total petroleum hydrocarbons as diesel (TPH-D),total petroleum hydrocarbons as gasoline ( PH-G) and associated benzene,toluene,ethylbenzene, and total xylene (BTEC compounds. Extraction of soil vapor at the site will ultimately facilitate remediation of impacted soil and groundwater. The purpose of AS is to remediate hydrocarbon-impacted soil and groundwater. In areas where soil has been impacted by petroleum hydrocarbons,naturally occurring microorganisms are present to biodegrade certain organic compounds. The microorganisms produce carbon dioxide (CO2) as a by- -product of aerobic biodegradation of hydrocarbon compounds. As soil gas oxygen (02) concentrations decrease due to microbial activity, soil conditions can become anaerobic,which significantly reduces the rate of contaminant biodegradation. During biodegradation of hydrocarbons, soil gas 02 concentrations are typically low (less than 5 percent),and CO2 concentrations may be high(greater than 10 percent). Soil vapor 02 concentrations in uncontaminated soil often are equivalent to that of ambient air (2,0.9 percent). The AS at the Facility is designed to stimulate naturally occurring microorganisms by injecting ambient air into air spargin'g.injection points to increase groundwater-dissolved oxygen (D.O.) concentrations and soil 02 concentrations, thereby enhancing aerobic biodegradationof contaminants at the site. 1.2 General System Description The SUETS consists of four 4 inch (101.6 millimeter (rnm)) diameter PVC vapor extraction wells (VW-1 through VW-4),belowground and aboveground PVC piping, air/liquid separator, catalytic oxidizer(oxidizer)unit,vacuum blower,manual blower flow recirculation valve,automatic and manual dilution air valves,associated aboveground valves and sample ports,electrical supply,and the control system. The AS consists of four 1 inch (25.4mm) diameter PVC air sparge injection points (AS-1 through AS-4),ABS Industrial piping, air injection compressor,heat reducing pipe manifold,and electrical service. The oxidizer manufacturer is King,Buck Technology.The Model MMC-5A oxidizer is rated at 100 cubic feet per minute [(cfin) (2831:7 liters per minute (L/min)]. Manufacturers'literature is presented in Appendix A. Design drawings"for the SVETS and AS are provided in Appendix B.Well construction logs will be provided in Appendix C.when available. Site..photographs will be presented in Appendix D when available. } - Soil vapor is removed from the vapor extraction wells utilizing a 5 horsepower [(hp) (3.73 kW)] D:\PNfP\Stockton Yard PD4P.doc .