ARCHIVED REPORTS XR0010036 - Laserfiche WebLink

Home Browse Search

b Soil Vapor&-traction and Treatment from Dual Phase Extraction The Soil Vapor Extraction(SVE)portion of the system would utilize existing combination groundwater monitoring/vapor extraction well MW-1 and two proposed vapor extraction wells VW-1 and VW-2. Proposed vapor extraction wells VW-1 and VW-2 will be drilled using a hollow stem auger drill rig to a depth of 20 feet below ground surface (fbg) and constructed with 2-inch diameter PVC casing, slotted at the appropriate intervals depending upon location and slotted for both vapor and groundwater withdrawal. The three wells will be connected by 2-inch diameter underground piping to a collection manifold located in the treatment compound. On the basis of preliminary design review the following approach to the on-site system would be used. The SVE should use a positive displacement blower, or the equivalent, with a capacity of at least 250 standard cubic feet per minute (scfm). Given the concentrations and volume of hydrocarbons in the subsurface, a thermal/catalytic oxidation unit is recommended. Installation of the VES would commence after obtaining the following approvals and permits: Approval of this CAP by the RWQCB-CVR and PHS-EHD; • An authority to construct (ATC) and permit to operate (PTO) from the San Joaquin r. Valley Unified Air Pollution Control District (SJVUAPCD) for the selected treatment equipment; and • A City of Tracy Building Permit • Pre-Approval from Underground Storage Tank Clean-Up Fund(USTCF) Immediately after obtaining the appropriate permits and approvals, the following tasks will be performed: • Procure all treatment system equipment and materials; and • install the treatment system and treatment compound. Monitoring of the vapor extraction system would consist of the following measurements: • VOCs in extracted vapors; • Total flow rate of extracted vapors; • System vacuum generated by the blower; • VOCs of vapors after treatment; and • System operating temperature. Periodic testing for TPHG and BTEX from individual extraction wells would be collected, and adjustments will be made to the system to minimize the duration of the cleanup. The VES will be designed for continuous operation, 24 hours per day, 7 days per week, until the concentration of hydrocarbons in the soil is reduced to asymptotic levels. A detailed description of the selected VES will be contained in the ATC permit application. Pase 13