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Lnapl Tn For Tceq Tf 2010 100504 Sec 1to3

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Lnapl Tn For Tceq Tf 2010 100504 Sec 1to3

  1. 1. LNAPL Transmissivity (Tn)Remediation Design, Progress and Endpoints<br />H2A Environmental, Ltd.<br />J. Michael Hawthorne, P.G.<br />mhawthorne@h2altd.com<br />May 2010<br />
  2. 2. Acknowledgements<br />Andrew Kirkman - AECOM<br />Mark Adamski - BP<br />Tim Smith - Chevron<br />Charles Stone - TCEQ<br />Roger Rinas - Valero<br />Dr. Charbeneau - UT<br />Dr. Huntley - SDSU<br />Dr. Sale - CSU<br />Introduction<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  3. 3. Questions Tn Can Answer<br />Understanding<br />What is the best way to quantify mobile LNAPL impacts?<br />How can I do this cost-effectively?<br />Comparison<br />I have 10 ft of diesel and 2 ft of neat toluene – How can I compare them?<br />Which one is more likely to migrate? How much more likely?<br />Which one will I be able to pump the most LNAPL from?<br />Which one will operate longer?<br />Prediction<br />How many bbls/gals will each well produce?<br />How long will my recovery last?<br />What remediation technology will be most effective/efficient?<br />Management<br />I manage 300 sites with LNAPL – How do I rank and prioritize potential migration risk and recovery potential?<br />I’ve been pumping water and LNAPL for years; Can I quit? When can I quit?<br />Introduction<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  4. 4. Analogs<br />Hydrogeology<br />Aquifer Testing yields K and T for water movement / production<br />Pumping Tests and Slug Tests<br />Normalizes all sites to one measurement standard to:<br />Analyze – Compare – Predict – Design<br />Multiphase Fluid Mechanics<br />Multiphase Saturation Distributions add Complexity<br />Different Fluid Properties Result in Different Flow Characteristics<br />Relative Permeabilities - Fluids Compete for Pore Space<br />Result: Generally Inhibited LNAPL Flow<br />Petroleum Engineering<br />Production Decline Curve Analysis<br />Rate Transient Analysis (RTA)<br />Expected Ultimate Recovery (EUR) Analysis<br />Introduction<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  5. 5. Outline<br />LNAPL Metrics for Hydraulic Recovery<br />LNAPL Transmissivity (Tn)<br />Definition<br />Determination<br />Applicability<br />Limitations<br />Tn and TRRP NAPL Mgmt Responses<br />TRRP-32 Endpoints<br />Remediation Design<br />Operational Performance<br />Examples (Not in Handout)<br />Introduction<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  6. 6. LNAPL Metrics in TRRP-32<br />Metrics for Hydraulic Recovery<br /><ul><li>Metric - a numeric or semi-numeric standard against which remediation need or progress is measured (e.g., Tn).
  7. 7. Decision Point - a Metric at which a change is made (e.g., de minimis liquid recovery so convert from MPE to SVE).</li></ul>End Point - a Decision Point at which an activity ceases (e.g., risk-based cleanup levels attained so remediation stops).<br />Metrics, Decision Points and End Points are captured in tables and flow charts in the TRRP-32 NAPL Management guide.<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  8. 8. Ideal LNAPL Metric<br />Collective Property <br />incorporates physical & chemical properties of the aquifer & LNAPL (e.g., permeability, viscosity)<br />Incorporates LNAPL Type (benzene vs. bunker oil)<br />Incorporates aquifer type (sand vs. clay)<br />Fundamental or Characteristic Property <br />Repeatable for given conditions<br />Saturation / Mass Driven<br />Multiphase saturation distribution<br />Varies directly with LNAPL mass<br />Easily Measured<br />Supported with multiple lines of evidence<br />Obtained prior to or during remediation<br />Metrics for Hydraulic Recovery<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  9. 9. Non-Ideal Metrics - Thickness<br /><ul><li>Inconsistent under varying hydrostatic conditions
  10. 10. Same mass exhibits different thicknesses in different soil types</li></ul>Metrics for Hydraulic Recovery<br />Modified after Kirkman (2009)<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  11. 11. Non-Ideal Metrics - Thickness<br /><ul><li>Tn increases with increasing recovery, thickness exhibits no clear trend but decreases with increasing recovery</li></ul>Metrics for Hydraulic Recovery<br />Modified after Kirkman (2009)<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  12. 12. Non-Ideal Metrics - Recovery<br />Benefits<br /><ul><li>Direct measure of remediation performance
  13. 13. Provides predictive data for decline curve analysis – EUR and Rate Transient analysis</li></ul>Metrics for Hydraulic Recovery<br />Problems<br /><ul><li>Strongly affected by system operational settings
  14. 14. Varies by technology – not directly comparable
  15. 15. Can’t be used to predict performance prior to startup</li></ul>©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  16. 16. Tn – An Improved Metric<br />Can be easily determined prior to, during and after remediation<br />Comparable across soil types<br />Comparable across LNAPL types<br />Comparable across Technologies<br />Comparable across unconfined, confined and perched conditions<br />Must understand LCSM<br />Must calculate drawdown correctly<br />Comparable between sites<br />Varies directly with LNAPL saturation / mass<br />Measures hydraulic recovery<br />Metrics for Hydraulic Recovery<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  17. 17. Section 2<br />Section Break<br />LNAPL Transmissivity (Tn)<br />Definition<br />Determination<br />Applicability<br />Limitations<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  18. 18. Tn Definition<br />Transmissivity (T) for water is the volume of water flowing through a cross-sectional area of an aquifer that is 1 foot wide X the thickness of the aquifer (b), under a hydraulic gradient of 1 ft/ft, in a given amount of time (e.g., 1 day)<br />LNAPL Transmissivity (Tn) is the volume of LNAPL flowing through a cross-sectional area of an aquifer that is 1 foot wide X the thickness of the mobile LNAPL interval in the aquifer (bn), under a hydraulic gradient of 1 ft/ft in a given amount of time (e.g., 1 day)<br />Transmissivity (Tn)<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  19. 19. Five Measurement Methods<br />Baildown Testing<br />Manual Skimming Testing<br />Recovery Data Analysis<br />Physical Properties Analysis<br />Tracer Testing<br />Transmissivity (Tn)<br /><ul><li>Critical References:
  20. 20. Huntley (2000) Groundwater
  21. 21. Charbeneau (2007) API
  22. 22. Sale et al (2007) Groundwater
  23. 23. ASTM (2010) Under Development</li></ul>©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  24. 24. Baildown Testing<br />Transmissivity (Tn)<br />Drawdown Calc (>0.5 feet)<br />Confined / Unconfined<br />Perched<br />Field Methods<br />Remove Borehole Volume<br />Minimize CGWS Disturbance<br />Boundary Conditions<br />Analytical Options<br />Bouwer & Rice<br />Discharge-based Methods<br />1/Q, s/Q, SSR<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  25. 25. Manual Skimming Testing<br />Basis – Skimming Recovery Equation<br />Field Methods<br />Remove Borehole Volume Repeatedly<br />Establish Sustainable NAPL Discharge<br />Minimize CGWS Disturbance<br />Applicability<br /><0.5 Feet or Rapid Recharge<br />Minimizes Gauging Errors<br />Equation:<br />Transmissivity (Tn)<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  26. 26. Recovery Data Analysis<br />Transmissivity (Tn)<br />NAPL only Removal<br />Skimming<br />Vacuum-Enhanced NAPL Removal<br />Vacuum-Enhanced Skimming<br />Water-Enhanced NAPL Removal<br />Total Fluids Pumping (Single or Dual Pump)<br />Water & Vacuum-Enhanced NAPL Removal<br />MPE<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  27. 27. Skimming (NAPL Only Removal)<br />Considerations<br />Adjust for bn changes<br />ln(Roi / rw) estimated at 4.6<br />bn(1-ρr) is max drawdown<br />If operating at less than max drawdown, use Qn and operating drawdown<br />Equation (Charbeneau 2007)<br />Transmissivity (Tn)<br />IDEAL<br />PUMP<br />DEPTH<br />NON-IDEAL<br />PUMP<br />DEPTH<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  28. 28. Vacuum-Enhanced Skimming<br />Considerations<br />If RaI not known, estimate RaI via Charbeneau (2007) equation – be careful in layered stratigraphy<br />1st equation uses air flow and open screen to calculate vac influence<br />2nd equation uses vacuum and ln(RaI / rw) to calculate vac influence<br />Equations (Charbeneau 2007)<br />Transmissivity (Tn)<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  29. 29. Water-Enhanced NAPL Removal<br />Total Fluids Pumping<br />Single or dual pump<br />Considerations<br />Simple Form (1st Equation) assumes swater is much greater than sn<br />If any doubt, use 2nd Equation<br />Equations<br />Charbeneau (2007)<br />Transmissivity (Tn)<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  30. 30. Water & Vac-Enh NAPL Removal<br />MPE – DPE or TPE<br />Considerations<br />If RaI not known from pilot testing/operation, estimate RaI as in VES<br />Air flow or Vacuum/RaI options similar to VES<br />Equations (derived from Charbeneau 2007)<br />Transmissivity (Tn)<br />Kirkman (2009)<br />Hawthorne (2010)<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  31. 31. Physical Properties / Modeling<br />Laboratory Analyses<br />NAPL Saturation<br />Grain-Size Analysis<br />Capillary Pressure Curves<br />Core Photography<br />and others<br />Modeling<br />LDRM<br />Input/Calibration Points<br />Kw / Tw / Tn / vG parameters<br />Saturation<br />Recovery Data<br />Outputs<br />Daily and Cumulative Recovery<br />Saturation Profiles<br />Specific / Recoverable Volumes<br />Tn thru Time<br />Transmissivity (Tn)<br />Capillary Pressure Curve<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  32. 32. Tracer Testing<br />Transmissivity (Tn)<br />Developmental Stage<br />Concerns<br />Localized Qf but large scale NAPL gradient<br />Uncertain Well Convergence Factor<br />Initially Capital Intensive<br />(Sale et al 2007)<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  33. 33. Tracer Testing<br />(Tim Smith, Chevron, 2010)<br />Transmissivity (Tn)<br />Field Test<br />Tracer Concentrations(UV/VIS spectrometer )<br />Gradient<br />LNAPL Thickness<br />Well Construction<br />Analytical Options<br />Calculate LNAPL flux through well<br />Calculate LNAPL flux through formation<br />Calculate Tn<br />Where: <br />Ct = Tracer concentration at time Dt (M/L3)<br />Co = Initial Tracer concentration (M/L3)<br />qwL = LNAPL flux through well (L/T)<br />Dt = change in time between measurements (T)<br />D = diameter of well (L)<br />bL = continuous thickness of LNAPL in the formation (L)<br />iL = LNAPL gradient (L/L)<br />a = flow convergence factor (L/L)<br />qfL = LNAPL flux in the formation (L/T)<br />TL = LNAPL Transmissivity (L2/T)<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  34. 34. Applicability – Uses for Tn<br />Inexpensive, numeric alternative to laboratory NAPL saturations<br />Calibration Parameter for multiphase model<br />API / Dr. Charbeneau – LNAPL Distribution and Recovery Model (LDRM)<br />Calibrate to initial pre-remediation Tn values (and other site data)<br />Calibrated Model Provides Predicted Values for:<br />Tn and specific/recoverable volumes over recovery time<br />Technology-specific recovery curves for LNAPL – rate and total volume estimates<br />LNAPL/water saturations through time versus residual/irreducible saturations<br />LNAPL thickness profile over time<br />Drawdown profile<br />Remediation Design Parameter<br />Operational Progress Metric<br />End or Decision Point for Hydraulic Recoverability – 0.3 to 0.8 ft2/day<br />Technical Impracticability Threshold for Hydraulic Recovery<br />Transmissivity (Tn) - Design<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  35. 35. Applicability - Scale<br />Individual Wells<br />Increased Precision<br />Reduced Area of Relevance<br />Collective Recovery Data<br />Decreased Precision<br />Travel Time Considerations<br />Interlocked Network<br />Interception / Capture Barrier<br />Increased Area of Relevance<br />Scale of Measurement<br />Match to Scale of Recovery<br />Transmissivity (Tn)<br />t3<br />t2<br />t1<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  36. 36. Limitations / Considerations<br /><ul><li>LCSM Critical
  37. 37. Regulatory Acceptance
  38. 38. Threshold Values Evolving
  39. 39. Tn applies only to hydraulic removal of LNAPL to the extent practical
  40. 40. Tn does NOT address dissolved or vapor phase risk-based drivers
  41. 41. Tn measures recoverable, not residual or total LNAPL, and therefore measures progress towards soilres</li></ul>Transmissivity (Tn)<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  42. 42. Section 3<br />Section Break<br />Tn and TRRP NAPL Mgmt Responses<br />TRRP-32 Applicability<br />Decision Points<br />Remediation Design<br />Operational Performance<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  43. 43. TRRP-32 NAPL Management<br />Tn and TRRP<br />Five (5) Step Process<br />TRRP-12A<br />Trigger Identification<br />Response Objectives / Endpoints<br />Design Phase (SIN / RAP)<br />Implementation / Evaluation<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  44. 44. TRRP-32 NAPL ManagementTn Application<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />Tn and TRRP<br />
  45. 45. NAPL Response Endpoint Types<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />Tn and TRRP – STEP 3<br />NAPL Response Endpoint Types<br />Recovery<br />Control<br />Recovery Only<br />Control via TI<br />
  46. 46. NAPL Response Endpoint Matrix(Migrating NAPL Zone Trigger)<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />Tn and TRRP – STEP 3<br />Nat. Control -NSZD<br />
  47. 47. NAPL Response Endpoint Matrix(NAPL Contact with GW Trigger)<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />Tn and TRRP – STEP 3<br />Alt. Tech – NSZD?<br />
  48. 48. TI Demonstration<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />RECOVERY ONLY<br />If Conventional & Alternative Technologies Cannot Achieve Endpoint.<br />RECOVERY<br />If Inability to File an Institutional Control Forces Site into Recovery and Conventional and Alternative Technologies Cannot Achieve Endpoint.<br />Requirements<br />Tool B - Qualitative Screen for TI of Individual Conventional Technologies Based on Site Characteristics Such as K – Should Not Take the Place of Site-Specific Pilot Testing, Analysis, Engineering and/or Design.<br />TI Requires Technically Rigorous Analysis of Time-Series Data from Operation of Alternative Technology Recovery System OR of Data from an Appropriate On-Site Pilot Test and Modeling Study.<br />Tn May be Incorporated into Site-Specific Pilot Testing, Analysis, Engineering and/or Design as a Direct Recoverability Threshold Metric and/or as a Calibration Parameter for a TI Modeling Study.<br />Tn and TRRP – STEP 4<br />
  49. 49. Conventional vs. Alt. Technologies<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />Tn and TRRP – STEP 4<br />
  50. 50. Conventional vs. Alt. Technologies<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />Tn and TRRP – STEP 4<br />Decision Pt. for Change from Hydraulic Recovery Technology Based on Tn<br />
  51. 51. Design Uses for Tn<br />Estimate upper boundary for specific discharge and seepage velocity – ignores entry pressure head. Valid for plume interior, not margins.<br />Calculate Average NAPL Conductivity from Tn and bn<br />Specific Discharge (Darcy Velocity or Flux) Equation Yields Volumetric Flow<br />Divide Specific Discharge by NAPL Filled Porosity to Get Seepage Velocity for NAPL - Yields Movement (distance per unit time)<br />Tn and TRRP – STEP 4<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  52. 52. Remediation Design and Tn<br />Direct Measure of Hydraulic Recoverability<br />Hydraulic vs. Pneumatic vs. Alternative Technology Selection<br />Modeled LNAPL Recovery Technologies<br />Calibrated to Readily Obtained Site Wide Tn Values<br />Technology-Specific Production Curves<br />Sustainability<br />Predicted Decline Curve Analysis for Rate and Total Volume Data<br />Relative Technology Performance Data – Technology Selection<br />Design Cost-Benefit Analysis<br />Projected Operational Lifetime<br />Capital vs. Mobile Infrastructure<br />Design Considerations<br />Equipment Sizing<br />Waste Mgmt / Recycling Volumes<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />Tn and TRRP – STEP 4<br />
  53. 53. Implement & Evaluate<br />Implement NAPL Management Strategy<br />Use Appropriate Monitoring Methods<br />Collect NAPL Response Action Performance Data<br />Conduct Evaluations after each Monitoring Event<br />Evaluations (all supported by Tn)<br />Ability of Response Action to Achieve Endpoints<br />NAPL Endpoints Achieved?<br />Should the Technology Change?<br />Is TI Supported by the Data?<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />Tn and TRRP – STEP 5<br />
  54. 54. Operational Performance Metric<br />Single Well Recovery Data Analysis During System Operation to Monitor Tn Progress<br />Combine with EUR and Rate-Transient Decline Curve Analysis to Evaluate Progress Towards Hydraulic Recovery Endpoint<br />Tn and TRRP – STEP 5<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />
  55. 55. Summary<br />Tn is an improved metric for hydraulic recoverability<br />Five calculation methods:<br />Baildown Testing<br />Manual Skimming Testing<br />Recovery Data Analysis<br />Physical Properties Analysis<br />Tracer Testing<br />Tn use as a metric<br />Indirect – model calibration parameter<br />Direct – recoverability (0.3-0.8 ft^2/day)<br />TRRP-32 and Tn<br />Design Parameter <br />Technology Selection<br />Production Rate<br />Production Lifetime<br />Model Calibration<br />Response Endpoints<br />Migrating NAPL Zone<br />Contact with GW<br />Decision Point<br />Conventional vs. Alt. Technologies<br />Augment Tool B for Technical Impracticability<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />Tn and TRRP<br />
  56. 56. Section 4<br />Section Break<br />Tn Examples<br />Not in Handout<br />©2010 by H2A Environmental, Ltd., All Rights Reserved<br />

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