ARCHIVED REPORTS XR0011199 - Laserfiche WebLink

Home Browse Search

3.0 VAPOR EXTRACTION SYSTEM OPERATION AND MONITORING i ' 3 1 System Operation During the quarter, the'system operated for a total of 1,498 hours (Appendix A) It operated for 25 days in April, 29 days in May, and 24 days in June During that period, 3,430,200 cubic feet of vapor r were extracted This brings the total to over 50,000,000 cubic feet since July 1994 New sample ports were installed on May 23, 1996 The new ports are located between the well heads and the knock-out drums Previously, the ports were located between the drums and the destruction unit The ports were relocated when Apache personnel began to suspect that the hoses and drums had become vapor-saturated and were contributing to the high PID readings that were obtained during the first quarter of 1996 3.2 Monitoring Summary r The extraction unit's on-board computer monitors several important parameters of engine performance, including air flow rates, well vacuum, and volume of extracted vapor These data are recorded hourly and averaged over the 24-hour day The daily averages are shown in Appendix A ' Hydrocarbon concentrations in the vapor stream (influent soil gas) and effluent (combustion products) were manually monitored on a weekly basis with a Microtip BL2000 photo-ionization detector In addition, vapor samples were collected from the effluent line and shallow well influent line on May 23 for comparison to the PID readings on that date The samples were collected in tedlar bags and ' delivered to Sequoia Analytical for analysis of TPH-g and BTEX concentrations The results, reported in milligrams per cubic meter, are shown in Appendix B , PID readings at the exhaust port ranged between 8 and 35 ppm during the quarter Effluent readings did not follow upward or downward trends in mlet concentrations PID readings from the deep well ' ranged from 223 to 1550 ppm prior to replacement of the sample ports, but only between 0 and 26 ppm thereafter PID readings from the shallow well ranged from 860 to 2220 ppm and averaged 1364 ' ppm No decrease was observed from the shallow well after the ports were replaced Readings from the combined flow line closely mimicked those from the shallow well prior to May 23, thereafter, no readings were taken from the combined inlet 4.0 DATA ANALYSIS 4.1 Graphical Summary ' Monthly summaries of daily air flow rates and other parameters for the second quarter are included in Appendix A In order to graphically illustrate the operation of the system, data for air flow rate since January 1996 and total cubic feet of extracted vapor since September 1995 are plotted in Figures 3 and 1 3 1 i