ARCHIVED REPORTS XR0000358 - Laserfiche WebLink

Home Browse Search

' GERAGHTY & MILLER, INC 6 feet per minute. Geraghty&Miller anticipates that operation of the air-sparging system will be required for approximately 2 years to attain the active remediation goals listed below The total ' anticipated operation and maintenance costs for the air-sparging system for this period are approximately $19,000 ($800/month) The use of a combination SVE/air-sparging system to simultaneously address source removal and enhance biological activity in the vadose zone and groundwater helps enhance the ' cost-effectiveness of this remedial alternative Geraghty & Miller recommends the adoption of the installed SVE/air-spargmg system as the primary remedial technology for the site PROPOSED CLEAN-UP LEVELS In accordance with the CVRWQCB Basin Plan, the ultimate project goal is to reduce ' concentrations of petroleum hydrocarbons to below the MCLs established for drinking water Benzene has an established MCL for drinking water of 1 µg/L The MCLs established for toluene, ethylbenzene, and xylene are 150 gg/L,700 µg/L, and 1,750 µg/L, respectively The ' current state action level for MTBE is 35 µg/L ACTIVE REMEDIATION GOALS Geraghty & Miller proposes that the system be operated until significant enhancement of ' bioactivity is shown through decreased concentrations of petroleum hydrocarbons in ground- water Operation of the SVE system will continue until the system is no longer effective on a ' mass-removal basis Effectiveness will be evaluated on the basis of SVE influent concentra- tions attaining asymptotic levels Bioventing can be implemented after the catalytic oxidation system is no longer required for hydrocarbon removal., as specified in the air permit from the San Joaquin Valley Unified Air Pollution Control District. ' Operation of the air-sparging system will continue to add oxygen to the subsurface until average concentrations of petroleum hydrocarbons have been reduced by approximately 95% rThis reduction goal corresponds to approximately 1 milligram per liter (mg/L} of TPH as gasoline and 10 µg/L of benzene in groundwater At that point, the air-sparging system will be ' turned off, allowing natural attenuation to achieve acceptable levels of petroleum hydrocarbons in groundwater It would not be cost-effective to operate the system until drinking-water lie objectives are achieved 1 Project No RC0309 010