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1 <br /> Working to Restore Nature <br /> 2 Air Flow Monitoring Equipment <br /> Air flow rates will be measured at individual wells using picot tubes installed in the <br /> lines upstream of the manifold. These pitot tubes will be attached to differential <br /> pressure dial gages (Magnehelic model #2006) <br /> 3 VOC Concentrations <br /> Monitoring at the site of the VOC's in the air stream before and after treatment will <br /> be done using a portable OVM model PID or Foxboro Model 108 FID type meter <br /> These units will be calibrated to either isobutylene or hexane respectively, and have <br /> a range of 1 ppmv to 10,000 ppmv Tedlar bag samples will be collected and <br /> laboratory analysis of samples will be performed to confirm the field results Inlet <br /> and exhaust gases will be monitored for total organic compounds <br /> Descrintion of Operation <br /> Phase 1 <br /> The insitu decontamination of soil will be accomplished by venting the vapor extraction <br /> wells to a Model TX-200 (200 cfm) thermal oxidizer VOC contaminated air will be pulled <br /> from six vapor extraction wells installed as shown in the attached plot plan Each of the <br /> wells will be plumbed to the remediation system with 2" dia schedule 40 PVC piping The <br /> individual wells will be manifolded at the enclosed compound A flow control valve, flow <br /> measurement device (pitot tube) insertion grommet and sampling port will be installed <br /> downstream of the manifold in each vapor line From the manifold the combined vapor <br /> flow will be passed through a vapor/liquid separator and then into the primary blower An <br /> LEL sensor downstream of the blower will control a fresh air inlet damper to adjust LEL <br /> levels The vapors are then passed through a flame arrester and into the combustion <br /> chamber Natural gas is used as a supplementary fuel source to maintain a combustion <br /> temperature of 1450 OF Residence time in the combustion chamber is 10 second When <br /> influent VOC concentrations drop below 15010 LEL, a catalytic module can be inserted to <br /> reduce supplemental fuel costs The air stream will be preheated to 750 °F prior to entering <br /> the catalyst <br /> Phase 2 <br /> The remediation system may be switched to granular activated carbon if the extracted <br /> hydrocarbon concentrations decrease to low levels and stabilize The switch will be made <br /> if the costs for carbon replacement is less than the operating costs for the thermal or the <br /> i 2 <br />