SITE INFORMATION AND CORRESPONDENCE_FILE 3

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• • Page 2 of 4 AA&A secured a Wastewater Discharge Permit from the City of Tracy Public Works Department to inject groundwater effluent from the DPE unit to the city sewer system. However, during the treatment event it was discovered that groundwater had sulfate concentrations in excess of allowable levels. AA&A immediately notified the City of Tracy and researched potential methods to treat the sulfate and ultimately concluded the water must be transported off-site to a proper disposal facility. A total of 47,005 gallons of contaminated groundwater were treated and discharged to the sewer system. Beginning on March 1, 2012,the water was transported and disposed by NRC Environmental Services, Inc., of Alameda, California. A total of 55,145 gallons of groundwater was disposed which required 12 individual shipments by truck. In total, approximately 105,445 gallons of contaminated groundwater were extracted in this event. AA&A bills the treated and discharged groundwater at CalClean's rates plus 15%mark-up, and bills the remaining groundwater sent for off-site disposal at cost plus 15%. On-site treatment and discharge is billed as follows: • $0.40 per gallon for the first 10,000 gallons • $0.34 per gallon for the remaining 37,005 gallons In total, $16,581.70 is billed for on-site treatment and discharge, and $17,330.50 is billed for off-site transport and disposal(cumulatively $33,912.20). Please note that the combined total billed for extracted groundwater is less than CalClean's maximum charge for water treatment/disposal of$31,000 per 30-day event plus 15% mark-up. Vapor samples were collected periodically from the individual wells or from combinations of wells to provide a record of the progress of treatment. Results of the initial vapor sampling on February 8, 2012, indicated that wells DPEI,DPE2, and DPE4 contained the highest TPHg concentrations at 4,800, 13,000, and 9,300 ppmv,respectively. By February 14, 2012,these concentrations had been reduced to 900, 1,100, and 1,700 ppmv of TPHg, respectively. A total of 2,057 pounds of TPHg were removed during the treatment period. The system employed by AA&A in this project is far superior to those used by competitors, and employs the following features: • SOIL-THERM Catalytic oxidizer with 30 KW electric heater and maximum capacity of destruction of approximately 750,000 BTU's of hydrocarbons per hour(with auxiliary air dilution) in soil-vapor or dual-phase extraction modes,with a capability of processing 50 to 500 scfin of air(with auxiliary air dilution blower); • High efficiency aluminum tube heat exchanger for preheat of incoming air; • Three 11.5-horsepower Siemens Model 7630 Vacuum Blowers, capable of extracting up to 375 cfin of air and inducing 22 inches of mercury (Hg) vacuum; • Stainless steel 60-gallon water knockout vessel with Goulds 1-1/2 hp pump capable of operating at vacuum levels up to 22"Hg; • 3.4-hp air dilution blower system with variable frequency drive for additional hydrocarbon destruction; • Automatic dilution air valve assembly; 7/9/2012