ARCHIVED REPORTS_XR0006705 - Laserfiche WebLink

Home Browse Search

Canepa's Car Wash 6230 Pacific Avenue Stockton,CA Third Quarter Groundwater Monitoring Report July 2005 - Page 6 of S The corrected values are averaged, then the units of measurement are converted from parts per million of volume (ppmv) to milligrams per cubic meter(mg/m3) - The average contaminant concentration for the penod is then multiplied by the total volume processed through the treatment system to yield total mass ' Vapor Phase Volume Measurements The airflow though the treatment system catalytic oxidizer has averaged approximately 270 cubic feet per minute (CFM) since system start-up During the third quarter of 2005 the average flow was approximately ' 276 CFM Approximately 50% of the airflow is from the groundwater air-stripper and approximately 50% from the array of nine soil vapor extraction wells Laboratory analysis of a vapor sample collected from the effluent of the air-stripper and another vapor sample collected from the effluent of the soil vapor I extraction wells, both collected at the time of start-up, indicated TPH-G concentrations of 2 9 and 690 parts per million (ppm), respectively The TPH-G input to the catalytic oxidizer, therefore, is primarily from the soil vapor extraction wells This is confirmed by weekly PID measurements ' Vapor Phase Concentration Measurements, Calculations, and Quantification During the third quarter 2005, vapor samples were collected from the catalytic oxidizer influent and ' effluent for laboratory analyses on June 6, and July 11 PID measurements of the influent and effluent were also collected at the same time that the laboratory samples were collected For the June 6, 2005 laboratory analyses, TPH-G was detected at 36 ppmv and 1 3 ppmv for the influent and effluent, respectively The TPH-G for the July 11, 2005 laboratory analyses from the influent and effluent was detected at 32 ppmv and 1 2 ppmv respectively Corresponding PID measurements for the June 6, 2005 analyses were 34 ppm and 0 4 ppm, and the measurements for the July 11, 2005 analyses were 14 ppm and 0 2 ppm respectively A correlation was created between the TPH-G concentrations obtained from the ' laboratory sample analyses and the PID measurement to provide an empirical correction factor for the PID measurements This correlation was created for concentrations from the system influent as well as the system effluent Monthly samples for laboratory analyses are collected from the system influent and ' effluent, and the correction factors for the PID is adjusted accordingly on an on-going basis Four PID measurements of the system influent and effluent were collected between June 6, 2005 and July 28, 2005 The: average PID influent measurement was 20 5 ppm and the average effluent measurement was 0 20 ppm The average PID reading is calculated using the above mentioned correction factor, resulting in an average corrected influent PID measurement of 31 05 ppm The average corrected PID ' value was multiplied by the laboratory-supplied conversion factor of approximately 4 mg/m' for TPH-G, resulting in an average influent concentration of 124 2 mg/m' An average airflow of 276 CFM was then used to calculate the mass of approximately 96 1 pounds of TPH-G removed by the system during the period A similar calculation procedure was followed for the system effluent to calculate the TPH-G released by the system to the atmosphere Using the airflow of 276 CFM, the mass of TPH-G released by the system was calculated to be approximately 2 8 pounds, resulting in a destructive efficiency of approximately 97 1% for the period ' Vapor Phase Destructive Efficiency Of the approximately 9,856 1 pounds of TPH-G removed by the soil vapor extraction system and air- stripper to date, the catalytic oxidizer destroyed approximately 9,706 8 pounds and approximately 149 3 pounds have been released to the atmosphere This results in an overall destructive efficiency of approximately 98 5% A worksheet showing the SVE calculations for the current quarter is included in Attachment D • ' CONDOR