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VW-5 30 360 VW-6 30 010 Although, the distance from VW-5 to VW-6 is the same, the vacuum is different The cause of this is the radius of the capture circle from well 5, which barely reaches well VW--6, whereas, the capture circle of well VW-4 reaches and extends beyond well VW-5 Vapor well VW-6 is operating and is withdrawing gasoline vapors The horizontal relationship between the vapor wells is shown to Figures 1 and 2 The capture radius for each well is shown as a light circle The radius of the circle is 30 feet, which is occurring in well VW-5 and occurring in all the other vapor wells The horizontal radius of the sparging circle (Heavy Circle) is 55 feet, which is calculated under point 3, according to "Handbook of Bioremediation, Robert S Kerr Environmental Laboratory" The amount of sparging air will be between 19 and 20 Cubic Feet per Minute (CFM), This is supplied by a Conde Number 6 Pump included in the Addendum This pump has a 3 horsepower motor If the water table falls, then the breakout pressure also falls The CFM of sparging air is dependent on the breakout pressure The operating Vapor Extraction System (VES) is removing 200 CFM and the maximum CFM of air from the sparging system will be under 24 CFM The sparging air will contain partitioned hydrocarbons and will be captured by the VES 2 The porosity of silty sand and silt is published in "Ground Water Contamination" by Philip B Bedient, Hanadi Rifai and Charles Newell, as between 43% and 46% These are the two main sod groups at this site There are 2 clay beds which have a published porosity of 42% The particle size for clay is <0 004 mm, for silt is >0 004<0 063 mm and for very fine sand it is >0 062 <0 125 mm The particle saes relate to the permeability of a soil unit We have updated our Hydraulic Conductivity calculations of Apnl 30, 1993 The correct Hydraulic Conductivity, for the area around the tank pit, is 15 0743 Feet/Day See The Brower and Rice Slug Test Sheet It is possible to use this conductivity to calculate the particle size, which is between 0 01153 and 0 00815 mm in diameter This equates to the silt material The main sods in the vapor extraction system are silts and silty sands The Radius of Influence of each well is 30 feet and the volume of soil for the present water table is 65,000 Ftp The volume of air space is calculated by multiplying the porosity by the soil volume, therefore, the volume of air within the radius of influence for one well is between 27,950 and 29,900 Fe The total volume for the 5 wells is between 139,750 and 145,500 Ft3 and the average is 142,425 Ft3 The vapor extraction system operates at 171 Ft3ftnute This means that every 13 9 hours there is a complete change of air in the system The amount of air sparging used is a maximum of 24 Ft3 so the amount of sparging air will not be a problem for the extraction system The amount of BTEX volatile chemicals will depend on the concentration in the groundwater As the concentration is reduced the amount of BTEX removed will be less The Henry Constant for BTEX is between 5 6 and 8 7 X10 atm-M3-Mole' According to the published documents any chemical which has a Henry's Constant higher than 10-5 will volatize the contaminate in the water 3 The sparging calculations are taken from "HANDBOOK OF BIOREMEDIATION" Included is a graph shown in Figure 3, which shows the Ratio of Sparge Pressure to Breakout Pressure Vs Ratio of Horizontal radius to Sparge Depth !q q v