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VftV01 San Joaquin Na0cy Air Pollution Control District Page 7 VOC influent specified for the oxidizer, the oxidizer efficiency, and flow rates of 100 cfm and 300 cfm. Extraction rates are the mass of TPHg, benzene, and MTBE removed from the soil, and the emission rates are the mass of TPHg, benzene, and MTBE discharged to the atmosphere after the extracted vapor has been treated. Calculations are presented below: Extraction Rate at 100 cfm in pounds per day: The rate formula is calculated using concentration units of micrograms per liter. The maximum influent TPHg concentration will be approximately 20,000 ppmv or 82,500 ug/1 (this will be controlled by dilution if necessary). Based on the analytical data from the vapor extraction testing, the maximum benzene concentration is expected to be 3.7% of the TPHg concentration, or 3,050 ug/l, and the maximum MTBE concentration is expected to be 2.6% of the TPHg concentration, or 2,150 ug/1. Table 6 summarizes laboratory data in units of micrograms per liter as well as volume parts per million. Formula for extraction rate: Rate(lbs/day)=Flow(cfm) x Conc.(gg/1) x 1440 min/day x 28.321/cf x 2.2046 E-9 lbs/gg Calculated Extraction Rate (TPHg): = (100 cfm)(82,500 µg/])(8.99 E-5) = 742 lbs/day Calculated Extraction Rate (benzene):= (100 cfrn)(3,050 gg/1)(8.99 E-5) = 27 lbs/day Calculated Extraction Rate (MTBE): = (100 cfm)(2,150 gg/I)(8.99 E-5) = 19 lbs/day Emissions Rate at 100 cfin in pounds-per da: The emissions rates are calculated using the same formula. The vapor concentrations have been reduced by the factors ascribed by the manufacturers for the typical catalytic oxidizer i.e., minimum 98% destruction efficiency. Emissions Rate (TPHg): = (100 cfm)(82,500 gg/1)(0.02)(8.99 E-5) = 15 lbs/day Emissions Rate(benzene): = (100 clm)(3,050 gg/l)(0.02)(8.99 E-5) = 0.5 lbs/day Emissions Rate (MTBE): = (100 cfin)(2,150 gg/1)(0.02)(8.99 E-5) = 0.4 lbs/day Extraction and Emission Rates at 300 cfm: The estimated extraction and emission rates at 300 cfm are triple those for 100 cfm operation. ESTIMATED OPERATIONAL PERIOD The estimated operation time of the vapor extraction system is based on the initial estimated mass of contaminants in the soil/free product and on the rate at which the contaminants can be removed from the subsurface. We have used the mass of MTBE in the subsurface to make these estimates. The mass of MTBE in vadose soils is estimated to be up to 70 pounds. If the anticipated initial vapor extraction rate of approximately 19 pounds per day could be sustained, cleanup could be completed within a period of 4 days. However, most of the contamination appears do be within relatively fine-grained soil. In our experience, the actual rate of extraction is significantly less than G:IGROUNDZEITULEBURGIVapor Extraction perm affEScvrltr,DOC