ARCHIVED REPORTS_XR0012618 - Laserfiche WebLink

Home Browse Search

-y J Chevron U,S.A. - Page 3 anticipated to have a tendency to collect near the bottom of the pea gravel backfill; therefor a perforated pipe volatile vapor collection system was installed around the bottom of open excavation prior to the replacement of new tanks in the open excavated tank pit. Perforated piping was also placed in the bottom area of the previous product line entering the tank backfill, as well as the waste oil tank removal location. J VaPm, e tllae r�^' 5+�4 t5 ttvj The second phase of the remedial effort addressed the possible lateral t 6 5 :tee movement of contamination from the tank excavation. The second phase system ssive si. included the installation of five battered soil borings at tiie perimeter of the iA tank removal excavation, in which vapor extraction wells were installed. These second phase vapor wells address deeper soil contamination and possible lateral akt�l migration of contamination, as well as enhancing the performance of the first a-+ phase component of the system. The second phase system shares the vacuum and 1.33 manifolding with the first phase system. A condensate collection system is included in-line with the system to accommodate vapor-to-liquid condensation. IN, As of this proposal date, the final design for the vapor extraction system has been completed at Chevron's request by Dames & Moore for future implementation utilizingthe piping installed at the subject property. Although ,.; the subsurface piping has been installed, the designed vapor extraction hardware $ has not been installed at the subjectp y, pra ert nor has the permitting been completed for the operation of the soil vapor extraction system. In the interim, quarterly monitoring of the existing ground water monitoring wells at the subject property P j pro ert has shown a marked increase in the resents of i DA11Es ti hfannE