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,(VYATC <br /> A S S O C I A T E S I N C <br /> test was approximately 1 5 hours in length Flowrates, applied vacuums, influent and effluent <br /> 1 volatile organic compound (VOC) concentrations, and temperatures were also monitored during <br /> the test Vapors were extracted using an internal combustion (IC) engine equipped with a 5-hp <br /> blower and a moisture knockout chamber Two influent vapor samples and one effluent vapor <br /> sample were collected during the test Results and field readings from the short-term vapor <br /> 1 extraction are summarized in Tables 4 and 6 <br />' During the vapor extraction test, extraction flowrates ranging from 47 to 57 cubic feet per minute <br /> (cfin)resulted in vacuums of up to 0 8 inches of water in vadose wells VW-5s and VW-2d located <br />' 17 feet from the extraction well No response was observed in wells MW-1 and VW-4, located <br /> dust 6 to 7 feet from the extraction well This may have been due to preferential pathways present <br /> �c J <br />' in the subsurface or because the wells are screened approximately 8 to 13 feet below the current � <br /> water table Vacuums of up to 0 5 inches of water were observed in well MW-3 located 87 feet <br /> away which is screened approximately 3 feet below the water table Laboratory results of the <br /> vapor samples indicated that volatile hydrocarbons were detected in the influent samples <br /> 1 Approximately 0 2 pounds of total petroleum hydrocarbons as gasoline (TPHg) was removed <br /> during the pilot test Laboratory results of the effluent vapor sample indicated a destruction <br /> 1 efficiency of approximately 70 percent for benzene and over 98 percent for all other constituents <br /> analyzed <br /> On November 24, 1998, a short-term air sparge test was initiated by ATC using vapor well VW- <br /> 5d as the air infection point Upon startup of the test, an air leak was observed 1n nearby vapor <br />' well VW-2s from an apparent crack in the well seal The test was terminated and provisions were <br /> made to abandon well VW-2s <br />' On February 17, 1999, ATC supervised the abandonment of vapor well VW-2s It was proposed <br /> in the workplan to pressure grout the well with neat cement from the bottom of the casing to the <br /> surface using a tremae pipe but an unknown obstruction was encountered at 9 feet bsg and it was <br /> not possible to lower the trenue pipe past this depth A direct push drill rig was used to attempt <br />' w 162574 OACAP report doc 5 <br />