Laserfiche WebLink
' 05 May 1997 <br /> . AGE-NC Project No 95-0112 <br />' Page 10 of 14 <br /> borings MW-2, MW-4 or MW-5 Analytical results of soil samples indicated a relatively uniform <br />' lateral spreading of contaminants, forming a bell-shaped plume <br /> Approximately 3,138 cubic yard of soil were estimated to have been impacted with a volume of <br />' 1,463 gallons of gasoline from the former operation of the UST at the site Petroleum hydrocarbon <br /> concentrations were assumed to decline at a consistent rate radially from the former UST location <br /> The extent of impacted soil prior to remediation is illustrated on Figure 3 Mass calculations are <br /> included in Appendix E <br />' 512 POST-REMEDIATION <br /> ' Soil samples from borings B-9, B-10 and probings PI through P5 were used to estimate the mass <br /> of hydrocarbons remaining atthe site Analytical results indicated significant decreases in the extent <br /> and concentrations of hydrocarbons beneath the foimer UST location Approximately 547 cubic <br /> yards of soil were estimated to remain impacted with a volume of 240 gallons of gasoline <br /> Approximately 90 gallons are located between 5 and 27 feet bsg, approximately 150 gallons are <br /> located between 33 and 54 feet bsg, with the highest concentrations centered near 40 feet bsg A <br /> cross-sectional view of hydrocarbons remaining at the site is illustrated on Figure 4 Mass <br /> calculations are included in Appendix E <br /> 1 <br /> 5 2 MASS CALCULATION OF RECOVERED PRODUCT <br /> ' The hydrocarbon mass removed during the operating period was calculated using the following <br /> equation M = C•Q•t <br /> Iwhere M = cumulative mass iecovered (kg) <br /> C =vapor concentration (kg/m') <br /> ' Q =extraction flow rate (m'/hr) <br /> t= operational period, in hours <br /> Between 20 December 1996 and 26 February 1997, the extraction unit operated a total of 1437 5 <br /> hours This data, the analytical results of the vapor samples and an average flow rate of 70 efm were <br /> used to calculate the approximate mass of extracted gasoline during these periods The mass L <br /> calculations`are attached in Appendix D <br /> ' The mass of hydrocarbons extracted from RW-1 between 20 December 1996 and 26 February 1997 <br /> was calculated to be approximately 812 kg or 179 lbs A gallon of gasoline weighs approximately <br /> 6 25 lbs The approximate volume of hydrocarbons as gasoline iemoved during this operational <br /> 1 <br />