Laserfiche WebLink
PUBLIC HEALTH SERVICES <br /> .o <br /> SAN JOAQUIN COUNTY <br /> ENVIRONMENTAL HEALTH DIVISION 0 <br /> Karen Furst, M.D. , M.P.H. , Health Officer <br /> 304 East Weber Avenue, Third Floor • Stockton, CA 95202 <br /> 209/468-3420 FILE COPY <br /> ROGER LISTON <br /> DARPETRO INC OCT 12 1998 <br /> 3450 EL CAMINO AVE <br /> CERES CA 95206 <br /> RE: Darpetro Exxon Site Code: 1060 <br /> 749 E. Charter Way <br /> Stockton, CA 95206 <br /> San Joaquin County Public Health Services Environmental Health Division (PHS/EHD) <br /> has reviewed the Work Plan dated August 21 , 1998 and the Work Plan Addendum dated <br /> September 23 , 1998, submitted by California Geophysical Group for the above <br /> referenced site. Due to the rising level of ground water at this site since the design and <br /> installation of the present Soil Vapor Extraction System (SVES) and due to continuing <br /> high levels of contaminants in the ground water, it is necessary to re-evaluate the design <br /> and function of the SVES. The above referenced Work Plan and Addendum are deficient <br /> and further information is required in order to clarify plans for investigation and <br /> remediation of contaminated groundwater and soil at this site. <br /> SOIL VAPOR EXTRACTION AND AIR SPARGE SYSTEM MODIFICATION <br /> 1 ) Regarding the Work Plan Addendum: Explain the equipment used to measure the <br /> vacuum of each Vapor Well (VW) . Explain what "Closest Well' means in relation to <br /> the intent of these measurements. On the graph where vacuum is plotted against <br /> horizontal distance show each individual VW as to its relation to other V Ws and Air <br /> Sparge Well (ASW). Relate this information to the projected performance of the Soil <br /> Vapor Extraction System(SVES) with the addition of Air Sparging (AS). Discuss <br /> rationale for adding more VW(s). <br /> 2) Provide calculations of the pore volume space and relate it to the extraction flow rate <br /> to project the pore volume exchange rate of SVES with AS . Discuss the intrinsic <br /> permeability of the soils at this site as it relates to AS and SVES . <br /> 3) Provide calculations to show how the determination was made in the Work Plan as to <br /> the following: <br /> • Migration rate and distance of air sparge air <br /> • Capture radius of extraction wells <br /> • Introduction rate of air sparging air and how it was estimated according to the Work <br /> Plan statement, "not to be too much air for the extraction system to handle". <br /> i <br /> i <br /> A Division of San Joaquin County Hcalrh Cam Serviccs <br />