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r A IS"n" C k✓ h3�L M- �A f �'+. kf+ +k. �!h-.' <br /> M- `k <br /> r <br /> 4 <br /> 7� 3 <br /> f� <br />`° 3�,� n.°,r'- �„-�. ,- �. aw'' �, "�,�` �� _•"W ";�^�yicr_+'a�1 �„'� ����� "ds-v 'h _ yk 5.�;;.,. <br />,�'y_:. �_� r..?.�.. y �,' ,� � .r"�"�i..M a_.. �.i^ 'ate ;�sm �'� .`a'� �'° ry`r�.,«� w .-�. :,a, 'M•��'' 3� <br /> Texaco Environmental Services September 1t, 1391 <br /> Page 1 <br /> 02320 0075 <br /> A soil venting pilot test was performed on May 21, 1991 to determine if soil venting could be used <br /> to remediate the subsurface soils. Existing MWs were used as vapor extraction points during the test,and <br /> vapors were extracted using a 1.5-horsepower(hp)regenerative blower. Results from the pilot test Indicate <br /> a conservative radius of influence of 25 feet. Air samples collected from MW-4 and MW-5 contained total <br /> petroleum hydrocarbons as gasoline(TPH-G)of 71,000 and 150,000µg/I,respectively. 14Ew:alise the MW <br /> aFe ccas- +effieif�h f, 'r opts'and winds rf <br /> soN vPt, tz)r have�bee <br /> prefera�3 ��t �td` pif3sry t;ing$in t1a`F+V +'�����ts>ra�ata�Uie�re�t��a;lpf�k�A�Qt tsYt rrtay, <br /> "riotdvnsli tate t�pper`�la�cod horJzoii wltereitt riiajq�tty of ttte sdspd�; droca <br /> �� rbnrt5 <br /> 3.0 PROPOSED SCOPE OF WORK <br /> 3.1 SOIL.VAPOR EXTRACTION WELL INSTALLATION <br /> Aa~�ege a'z5,to 3i] et tadlti§:of lnfl4 !>ce,txhaii uslnp a;1$hp_regen&r Vve.bjokr.four Vapor,- <br /> extraction wells.W i be required,tv.rprtiedlate_.Ute,aubsurface;a ils an attempt to isolate Individuals' <br /> �.� atraUgra,�lsfQF�oznra ti'or soil venting(the upper clay aril(ower sty;'sand),two VEWs Will be nested in eachr <br /> r�ibtfa Four 12-inch diameter soil borings will he drilled to a depth of 40 feet BGS,and each VEW wilf be <br /> constructed using 10 feet of 4-inch diameter PVC well screen and blank casing to the surface. Screen will <br /> be placed at depths of 5 to 25, and 30 to 40 feet BGS,a 2-to 3-feet thick bentonite seal placed between <br /> the two sections of screen will Isolate the nested VEW's from one another. A sand pack equivalent to <br /> number 3 Monterey sand will be placed in the annulus around the screened sections,and cement grout wifl <br /> complete the wells to the surface. Figure 5 (Appendix AM presents a construction diagram of the VEW. <br /> Figure 6 (Appendix A) presents the VIEW locations, their estimated radli of influence and the estimated <br /> horizontal extent of impacted soils In the subsurface. <br /> 3.2 SOIL VAPOR EXTRACTION TEST <br /> A soil vapor extraction test will be performed using the VEWs upon completion. Prior to conducting <br /> the test,permission will be acquired from the San Joageln County Air Pollution Control District(SJCAPCD). <br /> The test will be conducted to determine the radius of Influence and the hydrocarbon concentrations in soil <br /> vapors eytraated from the VEWs. Vapors will be drawn using a 1.5 hp regenerative blower. Flow rates <br /> during the test will be altered to aid in determining the size blower that will be required to achieve the <br /> desired radius of influence. Air samples collected during the test will be sent to a state-certified laboratory <br /> rte.CHOIi�h}}'A'1'Flt <br /> 0075COST.PRo TFCIISI)Lt)(�};11'C, <br />