ARCHIVED REPORTS XR0007487 - Laserfiche WebLink

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' Mr Lynn Walker �raiR13 November 28, 1995 (9347-3011) Soil Vent System Operation Aegis Environmental,Inc (now Fugro) restarted soil venting system operation (extraction from VF-W-1, VEW-2, VEW-3, and VEW-4) on June 23, 1993, while vapor extraction from monitoring well MW-3 commenced on July 8, 1994 Fugro has performed soil vent system monitoring in accordance with the requirements of the permits(Permit to Operate No N-1133-2-0 and Authority to Construct Permit No N-1133-2-1) issued by the San Joaquin Valley Unified Air Pollution Control District The soil venting system has been "pulsed," i e cycled on and off, at approximately two week intervals from February 23, 1995, to the present Pulsing is intended to increase the efficiency and the amount of petroleum hydrocarbons extracted by optimizing soil vapor recovery Attachment B includes system sampling/monitoring results and laboratory reports Hydmcarbon Extraction Rates and Cumulative Extraction Estimate Between July 3 and October 3, 1995, the TPH-G extraction rates have ranged from 0 4 to 0 7 lbs/day and an estimated 32 pounds of TPH-G extracted from the subsurface During the period between June 23, 1993 and October 3, 1995, cumulative TPH-G extraction from subsurface vapors is estimated at 1,584 pounds (270 gallons) Calculations of petroleum hydrocarbons extraction rates and cumulative volume of petroleum hydrocarbons removed are included in Attachment B Gormand! Water Pumping With Discharge to Sanitary Sewer Ground water recovery system operation (pumping approximately 3 to 5 gallons-per- minute each from wells RW-1 and RW-2) commenced on March 2, 1993 Pumping from RW-1 was discontinued on September 20, 1994, since no petroleum hydrocarbons were detected in the ground water samples collected from the well RW-1 during the previous three quarterly sampling events (August 16 and November 14, 1994 and February 22, 1995) Pumping from RW-2 was discontinued on October 3, 1995, based on conversations between Shell and the SJCPHS Quarterly sewer discharge sampling and reporting has been performed in accordance with the requirements of the discharge permit issued by the City of Stockton Municipal Utilities Department Attachment C is the third quarter 1995 sewer discharge report which includes (1) pumping rates, (2) total discharge to sewer, and (3) analytical results since system startup Sewer Discharge Parameters During the penod between March 2, 1993 and September 5, 1995, an estimated 6,144,317 gallons of ground water containing dissolved phase petroleum hydrocarbons were removed from RW-1 and RW-2 and discharged into the sewer To date, the TPH-G concentrations detected in the discharge water have ranged from less than 0 05 to 1 5 ppm, benzene concentrations have ranged from less than 0 0005 to 0 026 ppm An estimated 37 pounds of TPH-G were recovered by the ground water recovery system between March 2, 1993 and September 5, 1995 93473011 DSR -2 -