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I 1 ' . 13 April 2001 I AGE-NC Project No 96-0232 Page 2 of 14 2 1 GROUND WATER PUMP AND TREAT OPERATION The ground water pump and treat system was designed to operate at a maximum flow rate of 25 GPM,requiring ground water extraction from selected wells on alternating weekly shifts The first shift consisted of wells located in the south trench-line (EW-2, EW-4, EW-6 and EW-9) and the second shift consisted of wells located In the north trench-line (EW-5, EW-7, EW-8 and EW-10) IEach extraction well was adjusted to extract ground water at a flow rate of approximately 5 to 6 GPM, the discharge of treated water (effluent) to the Coldam ditch was adjusted at a flow rate of approximately 23 GPM Field notes of ground water pump and treat operation and maintenance activities are in Appendix A Based on effluent flow meter readings (Appendix A), approximately 2,474,726 gallons of treated water were extracted and discharged to the Coldam ditch during the first quarter 2001 under RWQCB General Order 5-00-119 for discharge to surface waters of ground water from cleanup of I petroleum fuel pollution Since Initiation of the ground water pump and treat remediation system on 20 November 2000, a total volume of approximately 3,479,771 gallons of MTBE-impacted water has been treated and discharged to the Coldanl ditch An RWQCB waste water discharge (NPDES permit no CAG915001) permit for discharge to the Coldani ditch was issued to Flag City Chevron by the RWQCB by letter dated 06 November 2000 (Appendix B) 2 2 GROUND WATER PUMP AND TREAT SAMPLING PROCEDURES Samples of ground water pump and treat influent and effluent water were collected from valved sampling ports located upstream and downstream the remediation system Receiving water samples were collected in the Coldam ditch approximately 50 feet upstream (R-1) and 80 feet downstream (R-2) of the point of discharge, R-1 and R-2 locations were approved by the RWQCB during a site Inspection on 22 November 2000 IGrab water samples were collected from influent, intermediate, effluent and receiving water locations utilizing I-liter amber bottles without a sample preservative and 40-m1 EPA-approved VOA vials containing 0 5 ml 18% hydrochloric acid as a sample preservative Care was taken to ensure that visible air bubbles were not present in the vials after filling and capping Ground water sample containers were labeled with a sample designation, date, time, and sampler's initials 2 3 LABORATORY ANALYSIS OF GROUND WATER PUMP AND TREAT SAMPLES Monthly influent and effluent grab water samples were logged on a chain-of-custody form, placed in a chilled container and transported to a California Department of Health Services (DHS)-certified Advanced GmEnvironmental,Inc I