ARCHIVED REPORTS XR0006372 - Laserfiche WebLink

Home Browse Search

vapor stream containing 0 03 mg/L as gasoline and 1 . 2% carbon dioxide, see Table 3 . The above results show that the weekly two hour venting of MW8 , is removing excess carbon dioxide and allowing oxygen transfer to occur A calculated 2 . 89 pounds of gasoline range hydrocarbons has been removed from MW8 as of June 27, 1996 , see Table 3 and Appendix B - Field Notes and Appendix D for methods and proceedures . SUMMARY There has been no evidence of floating product or product sheen on the groundwater an MW1 since April 14, 1992 and MW3 and MW10 since November 11, 1992 The last evidence of product, as a sheen in the condensate recovery system, was on March 1, 1993 . Vapor recovery has reduced the hydrocarbons in groundwater significantly since the May 25, 1990 sampling, see Table 1 . On January 31, 1996 a sample of the water being treated by air stripping inside the "Convault" was obtained for certified laboratory analysis This was accomplished to prove the suitability for dumping this cleaned water to the City of Stockton' s sanitary sewer This water (800 gallons) was discharged to sewer on February 20, 1996 . Since that time there . has been no additional discharge to sewer. Bio-venting of MW8 was initiated on October 26, 1994 Sample results obtained of the groundwater at and near MW8 suggests that this weekly venting is beneficial in controlling the migration of the gasoline hyrocarbon plume As of October 17, 1996 an estimated 12085 5 gallons of gasoline range hydrocarbons have been removed from the soil and groundwater beneath this site . The 12085 5 gallons consists of previously removed floating product (40 25 gallons) , condensation from vapor extraction (48 75 gallons) , pro3ected petroleum hydrocarbon vapor extraction-destruction using Thermal Oxidation (74849 pounds/6 25 = 11975 . 8 gallons) , projected petroleum hydrocarbon vapor extraction-adsorbtion using Activated Carbon (126 5 pounds/6 25 = 20 . 24 gallons) and venting of MW8 (2 89 pounds/6 25 = 0 46 gallons) No chlorinated solvents were detected in chromatogram comparisons of the vapor samples ; "i e " 1 2 Dichloroethene (DCE) - refpnt_ i cin time_ 7 079 mi niitpA Trichloroethylene (TCE) - retention time 3 023 minutes^ and Tetrachloroethylene (PCE) - retention time 3 75 minutes In the past, water samples from MW1 and MW6 were tested using EPA method 8240 and were below detection limits for these compounds, see Update Status Report 21, September, 1993 . Water samples obtained on March 4, 1994 from MW1, MW6, MW9 and MW11 were tested using EPA Method 8010 and were below detection limits for these compounds . Water and vapor samples obtained from MW1, MW6 and MW9 on April 19, 1995, were tested using EPA Metod 8260 . All PAGE 3 R603 UPDATE-45 11/07/96