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ill <br /> Page 3 f <br /> April 30, 1996 <br /> SVE As-Built Specification A <br /> l The AS/SVE system construction was completed in February 1995 according to the drawings and <br /> y <br /> specifications submitted to PHS/EHD. This original. . <br /> y <br /> ri final s stem used an internal combustion engine for <br /> off-gas treatment. In the fall of 1995, hydrocarbon concentration in the extracted soil vapor dropped <br /> below the trigger concentration of 500 ppmv, and the engine was replaced by carbon vessels for off- <br /> gas treatment. Piping changes were made by Soon Kim and Don Light during this replacement. Del <br /> Monte is in the process of making additional piping and process changes to resolve certain <br /> performance issues resulting from those piping changes. Upon completion of the process changes <br /> and resolution of performance issues,Del Monte will submit a revised process flow diagram and <br /> process description. <br /> I The operators data log shows a value of 10,000 ppmv for February 16, 1995. However;)we made <br /> many additional measurements after recalibration of the PID instrument, and found the vapor phase <br /> gasoline concentration to be more in the range of 6,000 ppmv. We believe that the initial volatile <br /> organic compound (VOC)concentration could be as high as 10,000 ppmv when the system is started <br /> 1 again; however,we expect the high level of VOCs to significantly decrease within a short period of <br /> i� <br /> time. <br /> Paragraph 4 - Paglf 2 <br /> The basic equation used to calculate TPH gasoline removed is the ideal gas law. PV=nRT. We <br /> measure pressure(P),temperature(T), and flow rate(V). R is the ideal gas constant, and we can <br /> calculate the number of modes of TPH gasoline(n)by assuming a molecular weight of 120 g/mole for <br /> gasoline, we calculate pounds of TPH gasoline removed. <br /> Paragraph 5 - Page 2 <br /> The new wells SVE-3 and 4 were constructed according to the well construction plan submitted to <br /> PHS/EHD by CH2M HILL'on November 1, 1995. The elevation of the screen interval was <br /> ` determined prior to the development of the well construction plan. Engineering judgment was used <br /> to decide on screen intervall elevation based on a review of historic groundwater level data. <br /> We are planning radius of influence tests for the new wells SVE-3 and 4. <br /> Paragraph 1 - Page 3 <br /> We believe rapid carbon break through that occurred in November and January was caused by excess <br /> relative humidity and condensation in the carbon vessels during a period of cold weather and higher <br /> than usual applied vacuum lCpressure. Piping changes are being made to adjust relative humidity and <br /> reduce condensate formation. These changes should extend the life of the carbon bed. <br /> Paragraph 2 - Page 3k, <br /> r Del Monte is working with the local air quality district in the implementation of system changes and <br /> has submitted an application for a modified Air Permit to Operate. <br /> lE <br /> 1 <br /> i <br /> PHSLET 1.DOC <br /> ! h d <br /> 1 l <br />