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/^GERAGHTY jtHf& MILLER, INC. Environmental Services "•GroundWater Engineering Hydrocarbon Remediation Education March 10, 1992 Mr. Todd Shank Environmental Engineer Department of Planning and Natural Resources 1118 Christiansted Watergut Homes St. Croix, U.S. Virgin Islands 00802 Re: Request for Temporary Authorization of Air Discharge in the Tutu Area, St. Thomas, U.S. Virgin Islands. Dear Mr. Shank: Geraghty & Miller, Inc. is formally requesting temporary authorization of air discharge in Tutu, St. Thomas. Geraghty & Miller will be conducting a ground-water investigation in the Tutu area in accordance with a work plan which has been approved by the U.S. Environmental Protection Agency (USEPA). The objectives of the work plan are to delineate the potential sources, the horizontal and vertical extent, and the potential migration pathways of petroleum hydrocarbon products in soil and ground water in the vicinity of Route 38 within the Tutu Well Site (see Figure 1). The ground-water investigation will include the installation of ten shallow monitoring wells and seven deep monitoring wells. Approximately 45,000 gallons of ground N water will be generated during the investigation, primarily during aquifer pumping tests and ground-water sampling. Figure 2 presents the layout of the proposed treatment system. Prior to discharge, the ground water will be treated by air stripping and carbon adsorption to meet federal drinking water standards. Table 1 presents volatile organic compounds (VOC) levels detected during previous sampling rounds of two existing water supply wells (FW n and T-l) located in the center of the Tutu Wells site (see Figure 1). These data represent results from the sampling rounds conducted in September/October 1990, February 1991, and June 1991. The FW H Well and the T-l Well are expected to be representative of 201 West Passaic Street, 3rd Floor •Rochelle Park, New Jersey 07662-(201) 909-0700 • FAX (201) 909-0567/0568 TUT OO6 1829 *64907* 64907 CERAGBTY & MILLER, INC. 2 the ground-water concentrations in the Tutu Wells Site. To develop the design basis (worst case) scenario, the highest concentration of each constituent detected during sampling of the FW n Well and the T-l Well was used as the influent concentration to the air stripper (Table 1) for CASE 1 (Figure 3). Since benzene, toluene, ethylbenzene, and xylenes (BTEX) may be present at higher levels than detected, the concentration of each was increased to 100 parts per billion (ppb) for CASE 2 (Figure 4). This modification provides a degree of conservatism such that if high concentrations of BTEX are present, the air stripper should be adequate to reduce effluent concentrations to discharge standards. Discharge standards shown in Table 2 have been established at USEPA Maximum Contaminant Levels (MCLs), or USEPA Maximum Contaminant Goals (MCLGs). Calculations show that an air stripper tower design having a diameter of 1 foot, a packed height of 8 feet, and an overall height of 14 feet will be adequate to reduce the influent concentration to the required level. The packing used in the design was 1-inch Jaeger Tripacks (typical for a small diameter tower). The limiting constituent establishing the packed height is 1,2-dichloroethene at a level of 400 parts per billion (ppb). The predicted effluent concentrations are presented on Table 3 for the maximum influent concentrations (CASE 1) and modification for BTEX (CASE 2). The air discharge is calculated to be 0.005 and 0.008 pounds per hour (lbs/hr), respectively, for CASE 1 and CASE 2 on Table 3. Flow rates to the air stripping system are expected to be the highest during aquifer pumping testing (10 gpm). Therefore, a design flow of 15 gpm was selected for the air stripping system. The process flow involves discharge from the wells to a feed tank, through the air stripper, carbon adsorption units, discharge line, and finally to the sanitary sewer. Figure 3 shows the process flow for CASE 1 and the discharge rate of the constituents in pounds per hour to the feed tank, atmosphere, carbon adsorption units, and sanitary sewer. Figure 4 shows the same information for CASE 2. The water treatment system will be located at the Esso gasoline station, on Route 38, in the Tutu area (see Figure 2). Construction of the water treatment system is anticipated to start TUT OO6 1S3O GERAGHTY & MILLER, INC. in mid-May 1992. Operation of the water treatment system will occur infrequently through November 1992 (see Table 4). At least two samples (one influent sample and one treatment effluent sample) will be collected and analyzed for volatile organic compounds using USEPA Method 524.2 during each operation of the treatment system to document the effectiveness of the treatment system. If you have any questions or require additional information, please call. Sincerely, GERAGHTY & MILLER, INC. Enclosure c: Leonard Reed, DPNR Ana Gloria Ramos, TEIC CM:gv *PROl301-«/031092.kr Clinton Moffatt Staff Scientist Thomas V. Danahy Senior Scientist/Project Manager , X^ — Daniel A. Nachman Vice President/Project Officer TUT OO6 1831 Table 1. Summary of Detected Concentrations of Volatile Organic Compounds in Ground -Water Samples Collected from September 1990 to June 1991, Tutu Service Station Investigation, St. Thomas, U.S. Virgin Islands. CONSTITUENT Vinyl Chloride 1 ,2-Dfchloroethene Chloroform Trfchloroethene 1,1,2-Trfchloroethene Tetrachtoroethene Benzene Toluene Ethylbenzene Xylene T-l 10/2/90 17J 28QJ R 56J R 120J 32J R R — T-1FR 10/2/90 12J 270J R 47J R 981 26J R R — T-l 2/5/91 7 200J ND 36 ND 100D 27 1 1 — T-l 6/5/91 5 400DEJ 0.9 72DJ 4 180DJ 3J 0.8J ND - pwn 9/26/90 - 75J - 61 - 25J — ND - - FWIIFR 9/26/90 - 61J - 4J — 181 - ND - — pwn 2/5/91 - 230D - 21 — 90D - ND - - pwn 6/5/91 — 130DJ - 12J — 34DJ - ND — - Constituent concentrations in mfcrograms per liter [parts per billion (ppb)]. D Compound was quantified using a secondary dilution by USEPA method 624. E Result is outside calibration range. J Result was detected below the reporting limit or is an estimated concentration. R Result is unusable and rejected. FR Sample ID suffix denotes Field Replicate of previous sample. ND Compound not detected. - Compound not measured. PR01301 -#2Aututb11.wk3 CO GERAGHTY & MILLER, INC Table 2. Design Basis Scenark) Influent Constituent Concentrations, Tutu Service Station Investigation, St. Thomas, U.S. Virgin Islands. CONSTITUENT Vinyl Chloride 1 ,2-Dfchloroethene Chloroform Trfchtoroethene 1,1,2-Trfchtoroethene Tetrachloroethene Benzene Toluene Ethylbenzene Xylene CASE1 MAX INFLUENT CONCENTRATION 17 400 1 72 4 180 32 1 1 — CASE 2 MODIFICATION FOR BTEX 17 400 1 72 4 180 100 100 100 100 MCL/MCLG 2 5 N N 3 N 5 1000(a) 700 10000 Constituent concentrations inmicrograms per liter [parts per billion (ppb)]. N No proposed MCLs/MCLGs. - Compound not measured, (a) Final Rule (effective July 1992). PR01301 -*2/tutUtab.wk3 CO 'A W GERAGHTY & MILLER, INC. Table3. Effluent Concentrations for Design Basis Scenario with 1 Foot Diameter Tower and 8 Foot Packed Depth, Tutu Service Station Investigation, St. Thomas, U.S. Virgin Islands. / / CONSTITUENT MAX INFLUENT CONCENTRATION Vinyl Chloride 1,2-Dfchloroethene Chloroform Trfchloroethene 1,1,2-Trfchloroethene Tetrachloroethene Benzene Toluene Ethylbenzene Xylene 17 400 1 72 4 180 32 1 1 - CASE1 CASE 2 EFFLUENT % MODIFICATION FOR BTEX EFFLUENT % CONCENTRATION REMOVED CONCENTRATION REMOVED 0.1 45 0.0 1.0 03 25 05 0.0 0.0 — 99.6 98.9 97.6 98.6 915 98.6 98.6 983 98.0 - 17 400 1 72 4 180 100 100 100 100 0.1 45 0.0 1.0 03 25 1.4 1.7 2.0 2.0 99.6 98.9 97.6 98.6 915 98.6 98.6 983 98.0 98.0 o ft: Constituent concentrations inmircogram per liter [parts per billion (ppb)]. Air Stripper: 1 foot diameter, 8 foot packed depth, 14 feet overall height. Flow is 15 gallons per minute (gpm). Liquid Loading Rate is 19.1 gallons per minute per square foot (gpm/sqft). Air to Water Ratio is 30 (volumetric). Air Rate is 60 cubic feet per minute (cfin). Temperature of influent is 84.5 degrees Fahrenheit (F). Packing is 1 inch Jaeger Tripacks. Limiting compound is 1,2-Dfchloroethene. H- 03 PR01301-#2AututbW.wk3 GERAGHTY & MILLER, INC H Table 4. Schedule of Ground-Water Discharges, Tutu Service Station Investigation, St Thomas, U.S. Virgin Islands. Weeks front Project Start (Start Date: April 2,1992) Activity Estimated Volume of Generated Ground Water (gallons) * Dates are approximate. VOC Volatile organic compound. Ibs. Pounds. Estimated Maximum Total VOC Discharge to Air Obs) 13-15 (July 2 -July 16)* 17-18 (July 30 - August 6) * 21-22 (August 27 - September 3) * 31-32 (Nov. 5 - Nov. 12) • Monitoring Well Development Monitoring Well Purging - Sampling Round I Step Tests and Pumping Tests Monitoring Well Purging - Sampling Round 2 Estimated Total 5,900 3,000 33,100 3,000 45,000 gallons 0.05244 0.02666 029413 0.02666 0.39989 Ibs. PRO 1301- Ul GERAGHTY & MILLER, INC. IDWS OAlt MTEM2 I FRJCT MOj WW30I IfU NO: - IBUWMC: TU-O* IOCOSD: MOfF»n 0*K«HT _____ [BWTEK MXOK LEGEND • SOIL BORING • SHALLOW MONITORING WELL A DEEPER MONITORING WELL • EXISTING SUPPLY WELL NOT TO SCALE GERAGHTY 9 MILLER, INC. SITE PLAN TUTU SERVICE STATION INVESTIGATION TUTU, ST. THOMAS, U.S. VIRGIN ISLANDS FIGURE r /* / / ILK. ? / ¥ "" \. ji/ii! It 1 ! UCHT Nt£ f 1 1 t 1 iOK. WATEfN. I [SEPARATOR N 1 '\~^~~~ } \ ! T I •«-«• • 1 1 1 1 -JLt NETAWMG wa. ^X B— • • ,UW-8 ESSO GAS STATION L_^ B OF t- ICC * - ^AM SIT PPER , ON UEHn'^OlQNttS.^ tttSCHARGE( (EFFLUENT)] •MT CAR WASH DOOR HEWHT L K.MW-100 .. MW-10* 5 i *"""" "*"""" —*—^ ii [0 ———————————————————— V § £ K ? »M.H. P5 ^ DISC I.H. MmUTY K -fo- WGE TO L£ ,LK XX ' — - - -^*" LEGEND — « —— >- SANfTARY SEWER UNE _. — ._ STORM SEWER UNE ILK* SANITARY SEWER MANHOLE ftopu F OC!^^Z^^^^^HHI^B 40 PI^ET auu. ———— ^ STQRM SEWER ^^.^ BAS|N ^Vmj^mc. ^SSf^'gaA. ^^^^ 51 ? JH*^ : WATER THEATMBNTSwiHyi LAYOUT nGURE ... ,,* L " r'm"LJ. 5S^H5£"!!:aat msSBSS ————————— TUTU. ST. THOMAS, us. VIRON ISLANDS CO H CD r"i 03 Figure 4. Process Row Diagram for CASE 2, Tutu Service Station Investigation, St. Thomas, U.S. Virgin Islands. Groundwater Fe«d Tank Feed Pump Air I Foot Diameter Air Discharge to the Atmosphere To Sanitary Sewer . . Carbon Adsorption Units CONSTITUENT Vinyl Chterfd* 1,2DfeMonMtrMrM Chloroform TrfehtorotlrMnt 1.1.2Ttlchloto«th«o« TdraehlorMlhcnt TohMm O O O O Xyl«n* Total ComVhMnt concentrations In pound* p«r hour (Ibt/hr). Giound-watw flow Is 15 galoot p«r minute (gpm). 0.0001 0.003 0.00001 0.00054 0.00003 0.00135 0.00075 0.00075 0.00075 0.00075 0.00800 0.0001 0.003 0.00001 0.00053 0.000028 0.00133 0.00074 0.00074 0.00073 0.00073 0.008 0.0 0.0 0.0 0.00001 0.000002 0.00002 0.00001 0.00001 0.00002 0.00002 0.00000 NO NO NO NO NO NO NO NO NO NO NO X^GERAGHTY 8 MILLER, INC. Environmental Services Ground Water Engineering Hydrocarbon Remediation Education March 11, 1992 Commissioner Leo Francis Department of Public Works #8 Sub Base, Crown Bay St. Thomas, U.S. Virgin Islands 00802 Re: Request for Temporary Authorization of Ground-Water Discharge to Sanitary Sewer in the Tutu Area, St. Thomas, U.S. Virgin Islands. Dear Mr. Restovic: Pursuant to our previous correspondence and discussions, Geraghty & Miller, Inc. is formally requesting temporary authorization of a ground-water discharge to the sanitary sewer in Tutu, St. Thomas. Geraghty & Miller will be conducting a ground-water investigation in the Tutu area in accordance with a work plan which has been approved by the U.S. Environmental Protection Agency (USEPA). The objectives of the work plan are to delineate the potential sources, the horizontal and vertical extent, and the potential migration pathways of petroleum hydrocarbon products in soil and ground water in the vicinity of Route 38 within the Tutu Well Site (see Figure 1). The ground-water investigation will include the installation of ten shallow monitoring wells and seven deep monitoring wells. Approximately 45,000 gallons of ground water will be generated during the investigation, primarily during aquifer pumping tests and ground-water sampling. Figure 2 presents the layout of the proposed treatment system. Prior to discharge, the ground water will be treated by airstripping and carbon adsorption to meet federal drinking water standards. Table 1 presents volatile organic compounds (VOC) levels detected during previous sampling rounds of two existing water supply wells (FWII and T-l) located in the center of the Tutu Wells site (see Figure 1). These data represent results from the sampling rounds conducted in September/October 1990, February 1991, and June 1991. The FW H Well and the T-l Well are expected to be representative of the ground-water concentrations in the Tutu Wells Site. To develop the design basis (worst case) scenario, the 201 West Passaic Street, 3rd Floor •Rochelle Park, New Jersey 07662-(201) 909-0700 • FAX (201) 909-0567/0568 TUT OO6 .1839 GERAGHTY & MILLER, INC. highest concentration of each constituent detected during sampling of the FW n Well and the T-l Well was used as the influent concentration to the air stripper (Table 1) for CASE 1 (Figure 3). Since benzene, toluene, ethylbenzene, and xylenes (BTEX) may be present at higher levels than detected, the concentration of each was increased to 100 parts per billion (ppb) for CASE 2 (Figure 4). This modification provides a degree of conservatism such that if high concentrations of BTEX are present, the air stripper should be adequate to reduce effluent concentrations to discharge standards. Discharge standards shown in Table 2 have been established at USEPA Maximum Contaminant Levels (MCLs), or USEPA Maximum Contaminant Goals (MCLGs). Calculations show that an air stripper tower design having a diameter of 1 foot, a packed height of 8 feet, and an overall height of 14 feet will be adequate to reduce the influent concentration to the required level. The packing used in the design was 1-inch Jaeger Tripacks (typical for a small diameter tower). The limiting constituent establishing the packed height is 1,2-dichloroethene at a level of 400 parts per billion (ppb). The predicted effluent concentrations are presented on Table 3 for the maximum influent concentrations (CASE 1) and modification for BTEX (CASE 2). The air discharge is calculated to be 0.005 and 0.008 pounds per hour (Ibs/hr), respectively, for CASE 1 and CASE 2 on Table 3. Flow rates to the air stripping system are expected to be the highest during aquifer pumping testing (10 gpm). Therefore, a design flow of 15 gpm was selected for the air stripping system. The process flow involves discharge from the wells to a feed tank, through the air stripper, carbon adsorption units, discharge line, and finally to the sanitary sewer. Figure 3 shows the process flow for CASE 1 and the discharge rate of the constituents in pounds per hour to the feed tank, atmosphere, carbon adsorption units, and sanitary sewer. Figure 4 shows the same information for CASE 2. The water treatment system will be located at the Esso gasoline station, on Route 38, in the Tutu area (see Figure 2). Construction of the water treatment system is anticipated to start in mid-May 1992. Ground-water will be pumped from proposed Monitoring Wells MW-10 and TUT OO6 1840 GERAGHTY & MILLER, INC. 3 MW-10D to determine aquifer characteristics (see Figure 2). Operation of the water treatment system will occur infrequently through November 1992 (see Table 4). At least two samples (one influent sample and one treatment effluent sample) will be collected and analyzed for volatile organic compounds using USEPA Method 524.2 during each operation of the treatment system to document the effectiveness of the treatment system. The temporary discharge piping will be installed in compliance with Occupational Safety and Health Administration (OSHA) regulations. Signs and physical barriers (e.g., caution tape) will be installed as needed to minimize physical hazards associated with discharge piping in pedestrian pathway areas. In addition, discharge piping will be removed from pedestrian pathway areas when the system is not in operation. If you have any questions or require additional information, please call. Sincerely, GERAGHTY & MILLER, INC. Clinton Moffatt Staff Scientist Thomas V. Danahy ^ Senior Scientist/Project Manager Enclosure c: May Cornwall, DPW Mirko Restovic, DPW Ana Gloria Ramos, TEIC CM:(v fPR0130lHT2rtBn92.hr Daniel A. Nachman Vice President/Project Officer TUT 006 1841 Table 1. Summary of Detected Concentrations of Volatile Organic Compounds in Ground-Water Samples Collected from September 1990 to June 1991, Tutu Service Station Investigation, St. Thomas, U.S. Virgin Islands. -i o 0- b CONSTITUENT Vinyl Chloride 1,2-Dfchtoroethene Chloroform Trichloroethene 1,12-Trichloroethene Tetrachloroethene Benzene Toluene Ethylbenzene Xytene T-l 10/2/90 17J 280J R 56J R 120J 32J R R - T-1FR 10/2/90 12J 270J R 47J R 98J 26J R R - T-l 2/5/91 7 200J ND 36 ND 100D 27 1 1 — T-l FWH FWIIFR FWn 6/5/91 9/26/90 9/26/90 2/5/91 5 400DEJ 75J 61J 230D 0.9 72DJ 6J 4J 21 4 180DJ 25J 18J 90D 3J 0.8J ND ND ND ND _ _ _ _ pwn 6/5/91 — 130DJ - 12J - 34DJ - ND - - Constituent concentrations in mfcrograms per liter [parts per billion (ppb)]. D Compound was quantified using a secondary dilution by USEPA method 624. E Result is outside calibration range. J Result was detected below the reporting limit or is an estimated concentration. R Result is unusable and rejected. PR Sample ID suffix denotes Field Replicate of previous sample. ND Compound not detected. - Compound not measured. PR01301 -#2/tututbll.wk3 GERAGHTY & MILLER, INC Table 2. Design Basis Scenario Influent Constituent Concentrations, Tutu Service Station Investigation, St. Thomas, U.S. Virgin Islands. CONSTITUENT Vinyl Chloride 1,2-Dfchloroethene Chloroform Trichloroethene 1,1,2-Trfchloroethene Tetrachloroethene Benzene Toluene Ethylbenzene Xytene CASE 1 MAX INFLUENT CONCENTRATION 17 400 1 72 4 180 32 1 1 — CASE 2 MODIFICATION FOR BTEX 17 400 1 72 4 180 100 100 100 100 MCL/MCLG 2 5 N N 3 N 5 1000(a) 700 10000 cH Constituent concentrations in mfcrograms per liter [parts per billion (ppb)]. N No proposed MCLs/MCLGs. - Compound not measured, (a) Final Rule (effective July 1992). PR01301-«/tututab.wk3 0- H- 03 •£• (A GERAGHTY 6? MILLER, INC Table3. Effluent Concentrations for Design Basis Scenario with 1 Foot Diameter Tower and 8 Foot Packed Depth, Tutu Service Station Investigation, St. Thomas, U.S. Virgin Islands. CASE 1 CONSTITUENT MAX INFLUENT CONCENTRATION Vinyl Chloride 17 1,2-Dfchloroethene 400 Chloroform 1 Trfchtoroethene 72 1,1,2-Trfchloroethene 4 Tetrachloroethene 180 Benzene 32 Toluene 1 Ethylbenzene 1 Xytene EFFLUENT CONCENTRATION 0.1 45 0.0 1.0 03 25 05 0.0 0.0 - % REMOVED 99.6 98.9 97.6 98.6 91.5 98.6 98.6 983 98.0 - MODIFICATION FOR BTEX 17 400 1 72 4 180 100 100 100 100 CASE 2 EFFLUENT CONCENTRATION 0.1 45 0.0 1.0 03 25 1.4 1.7 2.0 2.0 % REMOVED • 99.6 98.9 97.6 98.6 915 98.6 98.6 983 98.0 98.0 Constituent concentrations inmircogram per liter [parts per billion (ppb)]. Air Stripper: 1 foot diameter, 8 foot packed depth, 14 feet overall height. Flow is IS gallons per minute (gpm). Liquid Loading Rate is 19.1 gallons per minute per square foot (gpm/sqft). p Air to Water Ratio is 30 (volumetric). H Air Rate is 60 cubic feet per minute (cftn). Temperature of influent is 845 degrees Fahrenheit ( F). § Packing is 1 inch Jaeger Tripacks. !> Limiting compound is 1,2-Dfchloroethene. CD PR01301-#2AututbM.wk3 GERAGHTY & MILLER, INC Table 4. Schedule of Ground-Water Discharges, Tutu Service Station Investigation, St. Thomas, US. Virgin Islands. Weeks from Project Start (Expected Start Date March 2,1992) Activity Estimated Volume of Generated Ground Water (gallons) 13-15 (July 2 -July 16) • 17-18 (July 30 - August 6) * 21-22 (August 27 - September 3) * 31-32 (November 5 - November 12) * Monitoring Well Development Monitoring Well Purging — Sampling Round I Step Tests and Pumping Tests Monitoring Well Purging — Sampling Round 2 5,900 SjOOO 33,100 SjOOO Estimated Total 45,000 gallons * Dates are approximate. PR01301-#2/sgwd.l23 GERAGHTY & MILLER. INC. TUT OO6 1845 LEGEND SOIL BORING SHALLOW MONITORING WELL DEEPER MONITORING WELL EXISTING SUPPLY WELL NOT TO SCALE GERAGHTY 7 MILLER. INC. rtrauMntai SHTEPLAN TUTU SERVICE STATION INVESTIGATION TUTU, ST. THOMAS, U.S. VIRGIN ISLANDS fICURE 1 TUT OO6 1846 r /• 1 / MJi. i / 1' '"" W^ .FW-I i /| • i / V 1 1r! ' ! LIGHT POLE / t ' | i ! / Y 1 1 -i ! i t i i t ' MW«. ! i ! i fCTAMNC WAU ^/ a_A •M .MW-8 ESSO GAS STATION L^ B OFFICE ^^ _ * vMR STI IPPEfl , . . \. ———— r£CO KUUr^' m I CAraoN UNITS-' ^iwa HDSHT 8'-tf CAR WASH DOOR HEKSHT r-ff I L. _ __ _ >SMW-100 1 **"""'•— ~—»>.^_ l**"10 i """"*"-•——. 1i! Os / 4v ——————————————— ' COn r ill.H. 00 C3 f^ DISC y-SEWER 1 U.K. ^HIJTY PO 4.H. -V MRGE TO ME MANHOLE .£ XX\ -**^ LEGEND — • —— >- SANITARY SEWER LINE _. — ._ STORM SEWER LINE SCALE ot=BBM40 FEET *°t* SANITARY SEWER MANHOLE SCALE OC=MMMO FEET ^ STORM SEWER CATCH BASIN ——————————— s SSS5S5SJ5-- —— - TKSBSS —————————— TUTU. ST. THOMAS. U.S. VIR«N ISLANDS 03 Figure 3. Groundwator Process Flow Diagram for CASE 1, Tulu Service Station Investigation, St. Thomas, U.S. Virgin Islands. Feed TankO-n-n Few Purr d P Ak Stripper IFool Diameter ———— < Carbon Adsorption Units Ak Discharge to the Atmosphere To Sanitary Sewer CONSTITUENT VtnylChbrkfo 1^ DWttoroelhen« CMototbrm TiiclitofoeVittne 1«1|2 TrtCnfOfOfinene T«kMhtoroethen« Benzene Toluene Ehylbeniene Xytene c Tow H i O 0.0001 0.003 o.oooot 0.00054 0.00003 0.00135 0.00024 0.00001 o.oooot - 0.0053 <z> 0.0001 0.003 0.00001 0.00053 0.000028 0.00133 0.00024 0.00001 o.oooot •- 0.005 o 0.0 0.0 0.0 o.oooot 0.000002 0.00002 0.0 0.0 0.0 - 0.0003 <j[ NO NO NO NO NO NO NO NO NO •• NO Constituent concenkaHons In pounds per how (Ibs/hr). Ground water Row Is 15 gallons per minute (gpm). 03 *» 03 Rgtire 3, Groundwater Process Flow Diagram for CASE 1, Tutu Service Station Investigation, St. Thomas, U.S. Virgin Islands. Feed Tank Air Stripper 1 Foot Diameter Carbon Adsorption Units Air Discharge to the Atmosphere 0" «t CD •H •4Jo V- To Sanitary Sewer CONSTTTUENT Vinyl Chloride 1,2 OfcMoroetheira Chkwfoim Triehloroelheiw 1.1,2 TrlehtoroeViene Tetr«chtoro«th«n« Toluene EViylbenzene Xytene Total 0.0053 Constituent conoentrfttfons In pounds pot hour (Ibs/hr). Ground water flow ts 15 notions per minute (gpm). 0.005 0.0003 0.0001 0.003 0.00001 0.00054 0.00003 0.00133 0.00024 0.00001 0.00001 0.0001 0.003 0.00001 0.00053 0.000028 0.00133 0.00024 0.00001 0.00001 0.0 0.0 0.0 0.00001 0.000002 0.00002 0.0 0.6 0.0 NO NO NO NO NO NO NO NO NO NO c o !O 03 Figure 4. Process Row Diagram for CASE 2, Tutu Service Station Investigation, St. Thomas, U.S. Virgin Islands. •43O Groundwater Feed Tank r -0— Feml Pump Air Shipper (Foot Diameter Ah Discharge to the Atmosphere To Sanitary Sewer Cnrbon Adsorption Units CONS1TTXJENT Vinyl CNwH* • »Z Die* dot (Ml n v tit CnfOfOfoffll ttbaehtmotthtt* Dtnxtnt O O O O ToW ConiMiranl conetnballon* In pound* p«t hmir (fet/hr). Giound-watet How I* 15 orient per nrinute (gpm). 0.0001 0.003 0.00001 0.00054 0.00003 0.00135 0.00075 0.00075 0.00075 0.00075 O.OOBOO 0.0001 0.003 0.00001 0.00053 0.000028 0.00133 0.00074 0.00074 0.00073 0.00073 0.008 0.0 0.0 0.0 0.00001 0.000002 0.00002 0.00001 0.00001 0.00002 0.00002 0.00000 NO NO NO NO NO NO NO NO NO NO NO