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I04 October 2000 <br /> AGE-NC Project No 97-0290 <br /> Page 6 of 9 <br /> 3 3 SOIL-VAPOR EXTRACTION <br /> The SVE unit operated at varying rates during the observation period Extraction flow rates were <br /> calculated to range from 75 to approximately 90 scfm Typically, operation of the SVE averaged 85 <br /> scfm during the period An Induced vacuum (negative pressure) of approximately 25 to 28 Inches <br /> of water was measured in the piping between the blower and extraction wells An induced vacuum <br /> I of approximately 0 15 inches was measured at well MW- 2, a distance of 10 feet from the extraction <br /> well VW-1 and 0 01 Inches was measured at well MW- 1, a distance of 35 feet from the extraction <br /> network system <br /> IThe SVE unit experienced poor operation likely due to low oxygen content in the Influent vapor or <br /> high carbon dioxide level in the same Several start-up attempts were preformed to extract carbon <br /> I dioxide and Increase the oxygen content in the Influent, however the SVE operation over the quarter <br /> was limited over the later period of operation <br /> Hydrocarbon concentrations detected in influent soil-vapor samples were as follows <br /> • 0 17 May 2000 TPH-g was detected at 34,000 ug/l, benzene at 150 ,ug/l, toluene at 370 ,ugll, <br /> ethylbenzene at 120 ,ug/l and total xylenes at 460 µgll <br /> • 19 June 2000 TPH-g was detected at 12,000 µgll, benzene at 25µg11 toluene at 86 µg11, <br /> ethylbenzene at 45 ,ug/l and total xylenes at 280 µgll <br /> • 06 July 2000 TPH-g was detected at 29,000 ,ugll, benzene at 87 ,ugll toluene at 310 µg11, <br /> Iethylbenzene at 180 ,ug/l and total xylenes at 900 µg11 <br /> The analytical results are summarized on Table 2 The laboratory reports (MAI Sample Numbers <br />' 38244, 38245, 40778, 40779, 42266, 42267) Quality Assurance and Quality Control (QA/QC) <br /> reports and chain-of-custody forms are included in Appendix C <br />' Hydrocarbon concentrations measured in samples from the effluent stream in April and June <br /> indicated a minimum 95-percent rate of destruction <br />' Concentrations of extracted organic vapor measured with the OVM were low compared to TPH-g <br /> analytical results from soil-vapor samples The highest concentration of organic vapor measured with <br />' the OVM was 883 ppm <br /> I <br />' Advanced GeoEnwronmental,Inc <br /> 1 <br />