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ON SITE ANALYSIS <br /> In addition to the bag samples collected for the WEGE laboratory <br /> samples may be run on site using a Photovac 10550 PID <br /> chromatograph. <br /> The influent and effluent samples are collected from the same <br /> ports as the bag samples but 60 cc syringes are used to collect <br /> the sample and 0 . 5 cc of the vapor sample are then i.n3ected <br /> directly into the PID chromatograph. The resulting chromatogram <br /> is then compared to a standard calibration run on the same <br /> chromatograph prior to the sample run. <br /> During the ,initial month of operation, three effluent samples were <br /> obtained during the day and analyzed using the 10550 <br /> chromatograph. The highest value is used to calculate the VOC <br /> poundage per day produced Presently, an influent and an effluent <br /> sample are obtained upon arrival to the site. Adaustments are <br /> then made to the vapor extraction system: removal of liquids from <br /> the condensation traps; closing the air dilute valve to maximize <br /> vapor removal, without causing the REMOX Unit to shut down due to <br /> high temperature shut off (greater than 15500F) ; and closing the <br /> pump bypass to create maximum flow and vacuum from the wells. <br /> Once, these ad]ustments have been completed and the system has <br /> stabilized, influent and effluent samples are again obtained, <br /> along with samples from the individual extraction orifices <br /> (wells) . The site is then secured until the next visit. <br /> FLOW RATES <br /> Flow rates are measured at the site by use of orifice plates . <br /> A one inch orifice is placed in line for each well and a three <br /> inch orifice as used to measure the total flow. <br /> An orifice plate restricts the flow of air across it. This <br /> restriction causes a pressure drop across the orifice . By <br /> measuring the resulting pressure change across the orifice it is <br /> possible to calculate the air flow rate. <br /> The flow rate is calculated by the pressure drop (millimeters (mm) <br /> water) across a square edge orifice plate . <br /> Ve = CK sgr(P) Q = AVe <br /> Where . <br /> Ve= velocity in feet per minute ( fpm) <br /> C = Orifice Coefficient = 0 . 65 ( for orifice used) <br /> K = Constant = 794 . 6 mm water <br /> P = Pressure differential across the orifice <br /> Q = Flow rate in cubic feet per minute (CFM) <br /> A = Area orifice in square feet. 1" = 0 00545 ft2 <br /> 3" = 0 04909 ft2 <br /> Q = A X 0 . 65 X 794 . 6 X sgr(P ) <br /> page 5 of 8603 , 09/10/92 <br />