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' J <br /> Chevron Products Company 3 <br /> Chevron Service Station#9-0557,139 South Center Street,Stockton,California 6101/01 <br /> • Soil Selection and Analysis. Soil samples for shallow wells will be <br /> collected continuously. Selected soil samples will be sent under <br /> chain-of-custody procedures to a California State-certified laboratory <br /> and analyzed for the presence of total petroleum hydrocarbons as <br /> gasoline (TPHg), benzene, toluene, ethyl-benzene, and xylenes <br /> (BTEX compounds), and methyl tertiary butyl ether (MtBE). <br /> • Groundwater Well Development and Surveying. Upon <br /> completion of well installation, the wells will be developed by <br /> appropriate methods. A licensed surveyor will also survey the well <br /> elevations relative to a known benchmark. <br /> • Groundwater Sampling and Analysis. Groundwater samples will <br /> be collected from the monitoring wells and submitted to a California <br /> State-certified laboratory and analyzed. Collected samples will be <br /> analyzed for the presence of TPHg, BTEX compounds, and fuel <br /> oxygenates and lead scavengers including MtBE, tertiary butyl <br /> alcohol (TBA), di-isopropyl ether(DIPE), ethyl tertiary butyl ether <br /> (EtBE), tertiary amyl methyl ether (TAME), 1,2-dichloroethane, <br /> ethylene dibromide (EDB), ethanol and methanol. <br /> Field and Iaboratory procedures, providing a detailed description of the <br /> methods that will be employed to complete the above described scope of <br /> work, are presented as Attachment C. <br /> Dual Phase Extraction (DPE) Feasibility Testing <br /> SECOR will conduct a four-day DPE feasibility test using the four newly installed <br /> wells (MW-9A, MW-10, MW-11, and MW-12 [one 8-hour test per well]). DPE <br /> utilizes a 2-inch diameter groundwater extraction PVC pipe placed within each <br /> extraction well. A vacuum will be applied to the inner pipe such that groundwater <br /> is extracted, thereby depressing the water table and exposing a greater portion of <br /> well screen for soil vapor extraction. Extracted groundwater and soil vapor will <br /> be separated aboveground. The separated soil vapor will be routed to a <br /> catalytic/thermal oxidizer for hydrocarbon abatement. The separated groundwater <br /> will be routed to a holding tank for profiling and disposal after the test. A more <br /> complete description of DPE pilot test procedures is presented in Attachment D. <br /> Aquifer Test <br /> The aquifer test will consist of a step-drawdown and constant-rate pumping tests. <br /> Step tests will be used to evaluate maximum pumping rates,while constant rate <br /> tests will be used to evaluate aquifer parameters including transmissivity(T), <br /> storativity(S), specific yield (Sy), and conductivity(K). Extracted groundwater <br /> will be stored in a holding tank for profiling and disposal after the test or treated <br /> . and discharged to the sanitary sewer under permit from the local publicly owned <br /> [:1Chevron1905571REPORTS1Feasibility Studylworkplan.doc <br />