Laserfiche WebLink
System Operat4on Summary Soil Vapor <br /> Extraction and Emlosron Control System <br /> 620 West Charter Way Stocidon Califomxa <br /> System Operation, Equipment Modification, and Monitoring <br /> Aegis personnel commenced continuous system operation on September 17, 1992 in the <br /> thermal oxidizer mode Because of decreasing hydrocarbon concentrations after 2,498 <br /> hours of operation (January 7, 1993), the system was modified to operate in the catalytic <br /> oxidizer mode by addition of manufacturer supplied catalyst <br /> The system was shut down between March 5, and April 9, 1993 to replace a 5 horse <br /> power (HP) motor with a 7 5 HP motor to increase system operating vacuum <br /> Monitoring consisted of periodic site visits (at least monthly) to collect system operation <br /> parameters including operation hours, airflow/vacuum, oxidizer combustion temperature, <br /> and flame ionization detector(FID) measurements During system start-up in the thermal <br /> and catalytic oxidizer modes, oxidizer influent (influent) and oxidizer stack (effluent) vapor <br /> samples were collected and submitted for laboratory analysis of benzene, toluene, <br /> ethylbenzene, total xylenes, (BTEX), and total petroleum hydrocarbons as gasoline (TPH) <br /> concentrations as required by the air permit In addition, periodic influent and effluent <br /> samples were collected and submitted for BTEX and TPH analysis to obtain additional <br /> data to assess system performance <br /> The data collected were used to estimate the hydrocarbon mass flow rate through the <br /> system, the volumetric airflow, benzene and TPH extraction/emission rates, and <br /> cumulative TPH and benzene recovery from the subsurface <br /> System Sampling/Monitonng Results <br /> Between September 17, 1992, and September 1993, the system operated for 7,040 <br /> hours <br /> Results of system operation and remediation progress are illustrated in the following <br /> attachments <br /> Table 1 - TPH and Benzene Concentrations, and Extraction Estimates <br /> Table 2 - Summary of BTEX and TPH Analytical Results <br /> Table 3 - Summary of Quarterly Ground Water Sampling Analytical Results <br /> Graph 1- FID-based TPH Concentrations in Extracted Soil Vapors <br /> Graph 2- FID-based Average TPH Extraction Rates from Soil <br /> Graph 3- FID-based Cumulative TPH Recovery Estimate <br /> Graph 4- Laboratory-based TPH Extraction Rates from Soil <br /> Figure 3- Vacuum Measurements (4122193) <br /> Figure 4 - Vacuum Measurements (911193) <br /> Based on field FID monitoring, the TPH extraction concentrations have generally <br /> decreased from 28,000 to 140 ppmv This corresponds to TPH extraction rates of 840 9 <br /> and 9 lbs/day, respectively <br /> 91 246J LTR 2 <br />