WORK PLANS 2002 - 2013 - Laserfiche WebLink

Home Browse Search

ro/ ti..f 10 June 2008 AGE-NC Project No. 97-0312 Page 3 of 11 intersect the vadose zone, therefore is not suitable for the extraction during a SVE Test. AGE anticipates utilizing the new SVE well and not relying on the current ground water monitoring well system (screened at greater depths) at the site as direct SVE observation wells for the SVE Test; however,observations can be made from the monitoring wells to validate or evaluate any vertical influence of the vacuum extraction. The proposed shallow SVE Test will consist of three shallow SVE wells screened at 10 to 30 feet bsg. One SVE well will be used to extract soil-vapor while the other two SVE wells will be used as observation wells to evaluate the radius of influence of SVE at 15 and 30 linear feet from the active SVE well. The shallow SVE wells are proposed to be installed in the following locations: • A four-inch diameter,high vacuum SVE well(VW-1),screened between 10 and 30 feet bsg, will be located near the source area at MW-5. • A two-inch diameter,high vacuum SVE well(VW-2),screened between 10 and 30 feet bsg, will be located near monitoring well MW-8. • A two-inch diameter,high vacuum SVE well(VW-3),screened between 10 and 30 feet bsg, will be located near borings B9 and B20. Proposed high vacuum SVE well locations are depicted in Figure 2; general lithology beneath the site is depicted in cross sectional view B-B' on Figure 3; and the lateral extent of hydrocarbon-impacted soil is depicted in Figure 4. The proposed SVE screen intervals are located at depthsof known diesel and gasoline-impacted soil and down-gradient (northeast) of petroleum-impacted ground water. The wells are proposed at location suitable for future remediation. Initially, pilot borings for proposed SVE wells VW-1 through VW-3 will be advanced to a total depth of 30 feet bsg.The total depths of each borings and/or screen intervals may be adjusted in the field and will be based on field observations and field screening using an organic vapor monitor (OVM). Total depths of borings may vary according to geologic conditions encountered during drilling.The proposed SVE wells will be advanced utilizing a truck-mounted drill rig equipped with 12-inch diameter hollow-stem augers. Following completion of the four pilot borings,the high vacuum SVE wells(VW-I through VW-3) will be installed into the bore holes. Based on soil and ground water data collected during the previous site investigations,AGE proposes the installation ofthe high vacuum SVE wells in the area of the highest reported concentrations of adsorbed soil contaminants(i.e.,the former UST areas and Advanced GeoEnvironmental,Inc.