ARCHIVED REPORTS XR0002753 - Laserfiche WebLink

Home Browse Search

Atlantic Richfield Company 2 �P Y ARCO Service Station 4932.16 East Harding Way,Stockton CA May 10 2001 California Groundwater monitoringwells MW-1 MW-2 and MW-3 were set at , ' approximately 40 feet bgs and screened from 10 to 40 feet Groundwater monitoring/vapor extraction well (MW-4) was set at approximately 40 feet bgs and screened from 5 to 40 feet Vapor extraction well SVE-1 was set at approximately 30 ' feet bgs and screened from 5 to 30 feet Boring logs showing well completion details are available in SECOR's Site Assessment Report, dated November 6, 2000 Well construction details are summarized in Table 1 ' Initial groundwater samples collected from the groundwater monitoring wells in September 2000 were reported to contain TPHg, benzene, and MtBE at maximum ' concentrations of 166,000 ppb, 10,500 ppb, and 708,000 ppb, respectively (all from MW-4) Quarterly monitoring and collection of groundwater samples from the monitoring wells at the site is ongoing Based on September 2000 groundwater elevation data, depth to groundwater at the site ranged from 26 45 feet bgs to 27 60 feet bgs Based on depth to ' water data from the monitoring wells, groundwater flow is interpreted to be towards the northeast at a gradient of 0 005 ' MPE FEASIBILITY TESTING Pre-Test Activities ' Prior to initiation of field activities, SECOR obtained WE pilot test authorization from San Joaquin Valley Air Pollution Control District (Attachment B) The MPE system emission control system was exempt from District permitting requirements SECOR also prepared a site-specific Health and Safety Plan (HASP) The HASP is required by the Occupational Health and Safety Administration (OSHA) "Hazardous Waste ' Operations and Emergency Response" guidelines (29 CFR 1910 120), and by California Occupational Health and Safety Administration (Cal-OSHA) "Hazardous Waste Operations and Emergency Response" guidelines (CCR Title 8, Section 5192) The ' Health and Safety Plan was reviewed by the field staff and contractors prior to beginning field operations at the site ' Interim Remediation/Feasibility Testing SECOR performed feasibility testing at the site on February 12-16, 2001 Two separate MPE pilot tests were performed using existing groundwater monitoring well MWt, soil vapor extraction well SVE-1, and a combination of both wells Monitoring wells MW-1, MW-2, MW-3, and MW-4 were used as monitoring points during the course of ' the tests Well construction details are presented in Table 1 Total MPE testing time was approximately 96 hours ' MPE tests were performed using a 20 hp liquid ring vacuum pump connected to a H2 Oil Thermal Oxidizer(Therm-ox) for treatment of the extracted soil vapors prior to discharge to the atmosphere 1 ARCO 4932/MPE test doc