Laserfiche WebLink
CLEARw,�JER <br /> G R O U P, I ISI C. <br />' SOIL VAPOR EXTRACTION TEST PROTOCOLS <br /> 1 <br />' PURPOSE AND SCOPE <br /> The purpose of the soil vapor extraction test is to evaluate the feasibility of <br />' contaminant volatilization in the vadose zone as a remedial option at the site, 'and <br /> determine the number of vapor extraction wells necessary. In particular, the <br /> objectives of the test are to: <br />' • Determine the effective radius of influence of a single well, <br />' • Determine the optimal vacuum and flow rates for a single well to obtain a <br /> significant radius of influence, and minimize the number of required wells, <br />' • Determine the air permeability of the vadose zone to evaluate the feasibility of <br /> volatilization for the given contaminant at the site, <br /> a Determine the number of required wells to remediate the site through <br /> volatilization in a reasonable period of time (<5 years). <br /> IFIELD PROCEDURES AND EQUIPMENT <br />' Soil Vapor Extraction Test Procedures <br /> One to several different vapor wells or suitable monitoring wells are subjected to <br /> the vapor extraction test. A monitoring well may be considered suitable for a vapor <br /> extraction test if at least five feet of well screen is exposed above the water table. A <br /> vacuum source is attached to a given test well. The soil vapor extraction test is <br />' conducted in several steps on the test well. An initial step is conducted at a low <br /> vacuum and flow rate. Subsequent steps consist of increasingly higher vacuum and <br /> flow rates until a maximum vacuum and flow rate is reached, as determined by <br /> Iequipment limitations or site geology. During the test, vacuum is measured in <br /> surrounding monitoring points. Monitoring points may be other vapor wells, <br /> vapor points or suitable monitoring wells. Each step of the vapor extraction test is <br />' concluded on a test well when consecutive vacuum measurements from <br /> monitoring points differ by less than 0.1 inch water column within one-half to one <br /> hour. Influent air samples, and if required by the local air quality authority effluent <br /> air samples, will be collected for appropriate analyses by a State-certified <br /> environmental laboratory. The following data are collected during the pilot test: <br /> I <br /> Soil Vapor Extraction Test Protocols Page 1 of 5 December 16,1994 <br />