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MagnehelicTM gauges attached to the test well and individual monitoring points are used to measure vacuum A thermal anemometer, or a Pitot tube, inserted into a manifold attached to the test well, is used to measure vapor extraction flow rates If the vacuum is below 10 inches of water column, a thermal anemometer is used If the vacuum is greater than 10 inches of water column, the flow rate will be measured using a pitot tube and MagnehelicTM gauge An Alpha OneTM, or equivalent, air sampling pump is used to collect influent vapor samples into one liter TedlarTM bags from the manifold sampling port If necessary, effluent air samples are also collected into one liter TedlarTM bags A photo-ionization detector is used to measure volatile hydrocarbon concentrations in collected air samples An LEL/oxygen meter is used to measure percent LEL and percent oxygen in collected influent air samples One influent sample, and if necessary, one effluent sample,will be analyzed at a State-certified environmental laboratory for total petroleum hydrocarbons as gasoline according to EPA Method 8015 and for benzene,toluene, ethylbenzene and xylenes (BTEX) according to EPA Method 8020 Additional analyses will be performed as required by the permit or specific project requirements All data is recorded in a written log by the vapor extraction test technician Depending on equipment used, some data is also recorded in computer generated printouts or into electronic data logs Data Evaluation Radius f Influence The test is performed at several pressure/flow rate combinations (steps)to determine the optimal vacuum and flow rate needed to obtain a sufficient radius of influence for one well The radius of influence will be determined as the radius from the extraction well to a distance from the well where the measured vacuum is one percent of the applied vacuum(Buscheck&Peargin, 199 1) Alternatively,the radius of influence may be defined as the estimated distance from the extraction well where vacuums are not less than 0 1 inches of water (Johnson, 1994) This radius of influence is assumed to approximate the maximum distance from the extraction well at which contaminated soil will be remediated through volatilization Although there are limitations inherent in determining the radius of influence based on pressure distributions (Johnson & Ettinger, 1994), this method is generally accepted as a screening technique The radius of influence may not necessarily increase significantly beyond a certain flow rate and vacuum Therefore,the optimal vacuum and flow rate will be based on blower efficiency relative to the area of influence and may not necessarily be the maximum vacuum and flow rate This evaluation will be determined graphically by plotting the vacuums observed at each monitoring point versus the distance of the monitoring point from the extraction well for each step test Semi-log paper may be used to obtain a straight line fit through the data for each applied flow rate and vacuum In addition,the applied flow rates and corresponding vacuums for each test will be plotted on smear paper to evaluate the effect of vacuum on flow rates Perineabilgy Data collected from several monitoring points during each test will be evaluated to determine the permeability of the formation following the method outlined by P C Johnson, et al(1990)based on the flow rate and transient pressure distribution data Two different permeability calculations presented by Johnson, et al (1990) and summarized by Dupont(1993) can be performed depending on site parameters The first calculation assumes radial flow with no vertical leakage and relatively long screens (>10 ft) The second calculation assumes some vertical flow, shallow soil contamination and relatively short well screens (<10 ft) For a derivation and presentation of the calculations refer to the original references Number of Extraction.We Is Requircd Once an approximate permeability value has been obtained and is consistent with known subsurface lithology, the feasibility of reducing hydrocarbon contamination through vapor extraction in a reasonable period of time(<5 years) can be estimated using the model presented by P C Johnson, et al (1990) This model is based on the maximum contaminant vapor concentrations in extracted Vapors, residual soil contaminant composition, vapor pressure, assumed soil temperature and the ideal gas law and will be determined with the aid of the computer program called "HyperVentilate®" (Johnson, 1992) The number of vapor extraction wells needed to remediate the contaminated is soil within five years will be determined from the results of the pilot test and the feasibility calculations and is approximately equal to the estimated area of contamination divided by the area of influence of one well All CLEARWATER GROUP(SVE TEST) 2 revised June 29, 2001