SITE INFORMATION AND CORRESPONDENCE FILE 1

Home Browse Search

&I N 16 April 1997 AGE-NC Project No , 95 -0121 Page 5 of 9 destruction. Optimal destruction will depend on four operational parameters : combustion temperature, volume of processed vapor, oxygen level and the lower explosive limits (%LEL). Vapor samples will be collected on a montWy basis . The samples will be collected in Tedlar bags and transported to a state certified laboratory for analysis of total petroleum hydrocarbons quantified as gasoline (TPH-g) and volatile aromatics (benzene, toluene, ethyl benzene and xylenes : BTE&X). Selected vapor samples may also be analyzed for TPH as diesel (TPH-d ) and methyl tert butyl ether (MTBE) . All analysis will be performed in accordance with the appropriate EPA and/or DHS methods. During the "start-up" period for the SVE system, organic vapor monitoring will performed on a daily basis. The anticipated start-up period will be approximately one to two weeks. 3 4 PROPOSED IN-SITU AIR SPARGING SYSTEM IAS is proposed in conjunction with SVE concurrently at the site. The proposed IAS system would consist of compressor to inject air beneath the water table using air sparging points. Approximate air sparging point locations are depicted in Figure 7 - Proposed Air SperrgingPoinlLocations. The compressor will provide between 3 and 10 pounds per square inch (psi) of air to each sparge point. The injected air will volatifize dissolved hydrocarbons in ground water, and force hydrocarbon vapors into the vadose zone, where they can be withdrawn by the SVE system. 3 . 2 . 1 . PROPOSED IN-S/TU .AJR SPARGING 1NTECTION POINTS Installation of seven IAS injection points are proposed utilizing direct push technology (DPT). Each IAS injection point will be installed using AGES van-mounted Geoprobe probing unit equipped with 1 . 125-inch diameter probe rods. Probing rods will be cleaned prior to advancement in each borehole. Sparging points will be advanced to depths of approximately 30 feet bsg. Soil probe borings will be completed as IAS injection points using 3/8-inch diameter teflon tubing and 3 '/2-feet of 3/8 -inch diameter stainless steel screen. Glass beads (50- 100 mesh) will be used as a filter pack around the injection point. An five foot interval of bentonite will be placed above the filter pack and will serve as an annular seal. Portland Type II cement will be utilized to grout from the annular seal to surface grade. Proposed IAS injection point construction diagrams are included as Figures 8 - Proposed Air SpargingPoint Design.