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Department of Toxic Substances Control <br /> Edwin F. Lowry, Director <br /> J <br /> 10151 Croydon Way, Suite 3 <br /> Winston H. Hickox Sacramento, California 95827-2106 Gray Davis <br /> Secretary for Governor <br /> Environmental <br /> Protection <br /> (916)255-3717 <br /> MEMORANDUM <br /> TO: Hortensia Muniz, P.E. <br /> Project Manager <br /> Office of Military Facilities <br /> FROM: Mark Malinowski, RG <br /> Hazardous Substances Engineering Geologist <br /> Office of Military Facilities <br /> DATE: July 1, 1999 <br /> SUBJECT: REVIEW OF THE BIOVENTING/SOIL VAPOR EXTRACTION SITES <br /> REMEDIAL DESIGN (60%) FOR THE TRACY SITE, MAY 1999. <br /> General Comments <br /> 1. The Professional Engineers Act states that all engineering specifications,plans (drawings) <br /> and reports must be signed to indicate responsibility. Please ensure the 100% design <br /> document and all design drawings are signed by a professional engineer licensed in the <br /> state of California. Also include the license number for the engineer. <br /> 2. Future cross sections should depict,where appropriate, SVE wells and vapor monitoring <br /> wells (VMW) and associated screen intervals. Inclusion of SVE wells and VMWs will <br /> make it easier to review and evaluate well placement relative to lithology, soil gas results <br /> and expected influences. <br /> 3. Sections 4 of Volume 3 specifies that influent GAC concentrations will be used to <br /> determine if the ROD clean-up levels have been reached. Once influent concentrations <br /> have achieved ROD clean-up levels, the system will operate for one more week and then <br /> be shut down. According to Figure 4-2, all extraction and VMW will be sampled, and <br /> then the system will be shut down and moved to the next circuit. DTSC recommends that <br /> the SVE system be shut down prior to sampling the VMWs. <br /> DTSC preference is to not use contaminant concentrations from extraction wells as a shut <br /> California Environmental Protection Agency <br /> 0 Printed on Recycled Paper <br />