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(Figures 4-9). These figures show the charac- <br /> extraction tests <br /> teristic rapid early time decrease in observation well r_might <br /> Og <br /> of .ter which the data follow a linear trend (srom t <br /> line). The vapor permeability, k, calculated from thigh given <br /> rae- <br /> ranges from <br /> pes0obs��rvedto 660 dduringarcys wdrilling.hich was unThe expehigh lvapo t rial <br /> ti the Y material <br /> as well as <br /> abilities are probably reflective of the clean sandy <br /> noted during the drilling of vadose detailsells vp <br /> permeability <br /> earlier b�ortng� SB3 and Appendix A. <br /> calculations are shown in App <br /> ry <br /> it was calculated that steady state conditions wthe steadre y state <br /> at least one well cation of low was used t Thereforeuring each test. calculate the .radius <br /> solution to the eq <br /> of influence for rawells VP2 and VPI,extraction esradii <br /> respectively Thecalcula- <br /> 29 and 27 feet f Appendix A. <br /> tions are shown in App <br /> site has <br /> Saeed on the test data, the adequate permeability for <br /> the method of <br /> vapor extraction. The dato <br /> n and others (1990) predict the total odeled time time to <br /> Johnso <br /> an <br /> removectedly f short the he traction period place.ydrocarbons in 1-50 days)d and gisPSnot <br /> unexpectedly The <br /> entirely consisten Pwith 2 show rapid decline in (Appendix <br /> curing <br /> sample data from V 1 however, the <br /> the first two hours of testing (5200 to increased) slightly. This <br /> sample collected at 252 minutes actually <br /> r affect was also observed in the two samples collected fAppendix <br /> VP1 which increase that the contaminants are ith time: from 5400 to Onot'distributed <br /> s) . This indicates which violates one of the model <br /> evenly within the subsurface, <br /> J• assumptions. This irregular hirssectionributi observed <br /> on dduring hydrocarbons <br /> ills <br /> consistent with the stratig p <br /> Ing as well as the soil sample Results. <br /> ence of drocarbon <br /> ^- <br /> The lack of homogeneity an bili Y soils willthe presyresult in uverall <br /> nation within lower perm is notpossible to quare <br /> lower hydrocarbon extraction rates. Ire present dt a but where ex <br /> - <br /> lower <br /> this. potential effect with the p <br /> traction rates are limited by the rate be d educe° dsign ficantly. <br /> cy of the vapor extraction system may val o <br /> _ remo <br /> Efficiency is defined ot�f <br /> geneotiles rate Tor a homogeneous <br /> us contaminant distr bution <br /> distribution. <br /> made <br /> A conservative estimate of the total remediation <br /> time %)a With a <br /> using the model referenced above (reduction <br /> oan an <br /> worst <br /> 10% efficiency factor. This app Dale of 500 days at the <br /> case timeframe for reaching .cleanup 9 <br /> v etoperational <br /> extraf f:lon rate of 85 cfm. At the, <br /> to 200 c fmheatimeframe <br /> --T -—_-_ <br /> ---traction.-ratesof approximately <br /> maybe shortened proportionally to-'21Q-to-280-days.__ <br /> PI _ <br /> 3 <br /> f <br />