ARCHIVED REPORTS XR0008160 - Laserfiche WebLink

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i R604 :UPDATE 11-JULY, 1992 ! Southeast of Tank Excavation near SB2 - AREA n ; ! Soil boring SB3 revealed soil contamination at the 30 and 35 foot !ra ` depths of a highly degraded gasoline (no light range petroleum hydrocarbons with Benzene and Toluene being below detection ! J limits . ► Subsequent borings east and north of SB3 ( SB8 and SB10 r it respectively) were below detection limits , indicating a limited lateral extent. 11 Soil borings drilled west and southwest of SB3 also detected soil i contamination but with greater vertical extent (SB9 and SB11 ) . �! Soil, boring SB12 was slant drilled beneath the building at 30c" off of vertical . The sample results and field screening showed this boring to be clean, thus showing lateral extent south of the tank area and SB9 and SB11 . ; ! SB3 , SB5 , SB9 and SB11 were converted into vapor extraction wells on July 22 , 1992. s E VAPOR EXTRACTION VAPOR RECOVERY SYSTEM AND MONITORING As stated in the Update Status Report #6 , wells P1 , P3 , EX, MW1 . and MW5 are manifolded to a vapor extraction system with .individual valved orifices for flow control and measurement from the individual wells . Since the completion of the confirmation soil sample borings , P1 has been destroyed and four new vapor extraction wells (VSB3 , VSB5 , VSB9 and VSB11 ) have been added to the vapor extraction system. The individual wells are fitted with PVC "T" heads ( 4" reducing to 211 ) with locking air tight caps , for well access . The "T" laterals ( 211 ) are fitted with 1/4" pipe to tubing fittings for obtaining vacuum/pressure and temperature readings . Pipe to hose 21' unions are placed between the "T"s and the 2" PVC flex hoses that go from the well to the extraction manifold. At the manifold the individual wells are connected to their own 2" PVC riser ( 36" in heigth) with an orifice plate and a gate valve at the top of the riser . Vacuum/pressure ports are i located on either side of the orifice plate. Each orifice (well ) has its own manometer (calibrated in millimeters (mm) water ) which � is hooked to the ports for continuous measurement of flow from a `Old ! particular well . All the extraction wells are manifolded together , above the gate valve to a set of two orifice risers that are in parallel prior to the vacuum pumps . After the vapor stream leaves the manifold, it is then pulled into the pumps (two Rotron DR505 � i placed in series ) prior to entering the activated charcoal vapor scrubs . I£ breakthrough was found to be occurring through the 1st a carbon, this carbon was removed from the system; the #2 carbon was then placed into the #1 position and a new carbon placed on the E exhaust as the #2 carbon. 3I page 4 I