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I I 20 March 1996 AGE-NC Project No 95-0130 Page 7 of 23 Emissions from the engine were routed through two catalytic converters to maximize the destruction rate of the extracted hydrocarbon vapors ' 42 PILOT TEST PROCEDURES The test began at 9 00 am and continued for approximately 8 hours Air-tight well caps, pre- I connected with magnehehc vacuum gauges, were attached to each well casing in VW-1 through VW- 3 Measurements were recorded at regular intervals throughout the test and are included in Table 3 The air stream from VW-1-13 was monitored for the presence of organic vapors using a PID The air I flow rate was monitored using a Dwyer DS-200 flow sensor The flow rate was determined from the measured differential pressure and the piping diameter using a nomograph I43 COLLECTION AND ANALYSIS OF VAPOR SAMPLES A total of five vapor samples were collected at two-hour intervals from the inlet of VW-1-13 to measure concentrations of extracted hydrocarbon vapors The samples were collected in Tedlar bags using a PID as an air pump IAfter collection, the samples were placed in a covered container and transported under chain-of- custody to McCampbell Analytical Inc (MAT) in Pacheco, California Each sample was analyzed Iwithin 72 hours of collection for TPH-g and BTE&X in accordance with EPA methods 8015m and 8020, respectively I 44 RESULTS OF VAPOR EXTRACTION PILOT TEST IVW-1-B was selected as the extraction well during the vapor extraction pilot test due to its favorably screened interval Flow rates ranged from 26 to 54 standard cubic feet per minute (scfm) at 0 25 to I 1 05 inches of water of differential pressure The induced vacuum stabilized at approximately 46 inches of water during the pilot test Hydrocarbon concentrations in the well effluent stream were measured at regular intervals PID field measurements ranged from 800 ppm to 1,500 ppm IThe greatest induced vacuum was measured from VW-1-A(screened interval 45 5 to 63 feet bsg) and VW-1-C (screened interval 8 to 23 feet bsg) Vacuum measurements ranged from 0 60 inches to 0 70 inches of water in VW-1-A during the final 2 hours of the pilot test, and 0 70 inches to 0 80 inches of water in VW-1-C during the final 2 hours of the pilot test Stabilized vacuum measurements ranged from 0 30 to 0 35 inches in VW-2-A, and from 0 25 to 0 30 inches of water in VW-2-B Stabilized vacuum measurements ranged from 0 20 to 0 25 inches in both VW-3-A and VW-3-B No