LNAPL Remediation Technologies - Revision history

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Jhurley: /* LNAPL Technologies */

2020-06-30T12:30:34Z

‎LNAPL Technologies

Jhurley at 23:32, 29 June 2020

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Jhurley: /* LNAPL Technologies */

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‎LNAPL Technologies

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Jhurley: /* ITRC Remediation Technology Selection Process */

2020-06-18T18:47:10Z

‎ITRC Remediation Technology Selection Process

← Older revision		Revision as of 02:09, 2 May 2022
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	'''Contributors:'''		'''Contributors:'''
−	[[Dr. Shahla Farhat \| Shahla Farhat]], [[Dr. Thomas McHugh \| ~~Tom~~ McHugh]], [[Dr. Phillip de Blanc, P.E. \|~~Phil~~ de Blanc]]	+	[[Dr. Shahla Farhat \| Dr. Shahla Farhat]], [[Dr. Thomas McHugh \|Dr. Thomas McHugh]], and [[Dr. Phillip de Blanc, P.E. \|Dr. Phillip de Blanc]]

@@ Line 7: / Line 7: @@
 *[[Petroleum Hydrocarbons (PHCs)]]
 *[[Vapor Intrusion - Separation Distances from Petroleum Sources]]
 '''Contributors:'''
-[[Dr. Shahla Farhat | Shahla Farhat]], [[Dr. Thomas McHugh | Tom McHugh]], [[Dr. Phillip de Blanc, P.E. | Phil de Blanc]]
+[[Dr. Shahla Farhat | Shahla Farhat]], [[Dr. Thomas McHugh | Tom McHugh]], [[Dr. Phillip de Blanc, P.E. |Phil de Blanc]]
 '''Key Resources:'''

@@ Line 3: / Line 3: @@
 '''Related Articles'''
 *[[LNAPL Conceptual Site Models]]
 *[[NAPL Mobility]]
 *[[Vapor Intrusion - Separation Distances from Petroleum Sources]]
 '''Contributors:'''
@@ Line 52: / Line 52: @@
 **Vacuum Enhanced Skimming: LNAPL and vapor are the phases removed.</onlyinclude> LNAPL drawdown via skimming and vacuum induces an LNAPL gradient toward the recovery point. Also referred to as bioslurping or vacuum enhanced fluid recovery (VEFR).
 **Total Liquid Extraction: LNAPL and water are the fluids removed.</onlyinclude> Drawdown of LNAPL and groundwater induces an LNAPL gradient toward the recovery point. Groundwater drawdown may expose submerged LNAPL thereby increasing LNAPL mobility and recovery rate. Groundwater extraction may also provide hydraulic containment of potentially migrating LNAPL. Also referred to as dual pump liquid extraction (DPLE)<ref name="ITRC2009"> Interstate Technology and Regulatory Council (ITRC), 2009.  Evaluating LNAPL Remedial Technologies for Achieving Project Goals (LNAPL-2). ITRC, LNAPLs Team, Washington, D.C. 157 pp.  [https://www.enviro.wiki/images/7/7a/ITRC-2009a_Evaluating_LNAPL_Rem_Tech.pdf Report.pdf]&nbsp;&nbsp;  Available from:  [https://www.itrcweb.org/GuidanceDocuments/LNAPL-2.pdf ITRC] </ref> (Figure 1)
-**Multi-Phase Extraction (MPE): LNAPL, water, and vapor are the phases removed.</onlyinclude> LNAPL drawdown, groundwater drawdown, and vacuum induce an LNAPL gradient toward the recovery point. Groundwater drawdown may expose submerged LNAPL thereby increasing the LNAPL recovery rate. Groundwater extraction may also provide hydraulic containment of potentially migrating LNAPL. Also referred to as dual-phase extraction (DPE) or two-phase extraction (TPE)<ref name="USACE1999">US Army Corps of Engineers (USACE), 1999. Engineering and Design: Multi-Phase Extraction, Engineer Manual. USACE, Washington, D.C. Manual No. EM 1110-1-4010, 286 pp. [//www.enviro.wiki/images/9/9b/USACE_1999-MPEmanual.pdf  Report.pdf]</ref>. MPE is also often used as a phase-change technology to expose submerged LNAPL (as well as LNAPL in the vadose zone) to volatilization and enhanced aerobic biodegradation with hydraulic LNAPL removal as a secondary remediation objective.
+**Multi-Phase Extraction (MPE): LNAPL, water, and vapor are the phases removed.</onlyinclude> LNAPL drawdown, groundwater drawdown, and vacuum induce an LNAPL gradient toward the recovery point. Groundwater drawdown may expose submerged LNAPL thereby increasing the LNAPL recovery rate. Groundwater extraction may also provide hydraulic containment of potentially migrating LNAPL. Also referred to as dual-phase extraction (DPE) or two-phase extraction (TPE)<ref name="USACE1999">US Army Corps of Engineers (USACE), 1999. Engineering and Design: Multi-Phase Extraction, Engineer Manual. USACE, Washington, D.C. Manual No. EM 1110-1-4010, 286 pp. [//www.enviro.wiki/images/9/9b/USACE_1999-MPEmanual.pdf Report.pdf]</ref>. MPE is also often used as a phase-change technology to expose submerged LNAPL (as well as LNAPL in the vadose zone) to volatilization and enhanced aerobic biodegradation with hydraulic LNAPL removal as a secondary remediation objective.
 *'''Enhanced LNAPL Recovery (three variations):'''
@@ Line 187: / Line 187: @@
 *[https://www.api.org/oil-and-natural-gas/environment/clean-water/ground-water/lnapl American Petroleum Institute LNAPL Portal]
-*An Illustrated Handbook of LNAPL Transport and Fate in the Subsurface, 2014. Contaminated Land: Applications in Real Environments (CL:AIRE). [//www.enviro.wiki/images/1/12/CLAIRE_2014_LNAPL_Illustrated_Handbook.pdf  Report.pdf]  Also available from: [https://www.claire.co.uk/useful-government-legislation-and-guidance-by-country/77-risk-assessment-info-ra/208-assessing-risks-to-the-water-environment-info-ra2-3 CL:AIRE]
+*An Illustrated Handbook of LNAPL Transport and Fate in the Subsurface, 2014. Contaminated Land: Applications in Real Environments (CL:AIRE). [//www.enviro.wiki/images/1/12/CLAIRE_2014_LNAPL_Illustrated_Handbook.pdf Report.pdf]  Also available from: [https://www.claire.co.uk/useful-government-legislation-and-guidance-by-country/77-risk-assessment-info-ra/208-assessing-risks-to-the-water-environment-info-ra2-3 CL:AIRE]
 *Interstate Technology and Regulatory Council (ITRC), 2009. [https://www.itrcweb.org/GuidanceDocuments/LNAPL-1.pdf Evaluating NSZD at Sites with LNAPL (LNAPL-1)]

@@ Line 49: / Line 49: @@
 **  Total Liquid Extraction: LNAPL and water are the fluids removed.</onlyinclude> Drawdown of LNAPL and groundwater induces an LNAPL gradient toward the recovery point. Groundwater drawdown may expose submerged LNAPL thereby increasing LNAPL mobility and recovery rate. Groundwater extraction may also provide hydraulic containment of potentially migrating LNAPL. Also referred to as dual pump liquid extraction (DPLE)<ref name="ITRC2009"> Interstate Technology and Regulatory Council (ITRC), 2009.  Evaluating LNAPL Remedial Technologies for Achieving Project Goals (LNAPL-2). ITRC, LNAPLs Team, Washington, D.C. 157 pp.  [https://www.enviro.wiki/images/7/7a/ITRC-2009a_Evaluating_LNAPL_Rem_Tech.pdf Report.pdf]&nbsp;&nbsp;  Available from:  [https://www.itrcweb.org/GuidanceDocuments/LNAPL-2.pdf   ITRC] </ref> (Figure 1)<onlyinclude>
 **  Multi-Phase Extraction (MPE): LNAPL, water, and vapor are the phases removed.</onlyinclude> LNAPL drawdown, groundwater drawdown, and vacuum induce an LNAPL gradient toward the recovery point. Groundwater drawdown may expose submerged LNAPL thereby increasing the LNAPL recovery rate. Groundwater extraction may also provide hydraulic containment of potentially migrating LNAPL. Also referred to as dual-phase extraction (DPE) or two-phase extraction (TPE)<ref name="USACE1999">US Army Corps of Engineers (USACE), 1999. Engineering and Design: Multi-Phase Extraction, Engineer Manual. USACE, Washington, D.C. Manual No. EM 1110-1-4010, 286 pp. [[Media: USACE_1999-MPEmanual.pdf | Report.pdf]]</ref>. MPE is also often used as a phase-change technology to expose submerged LNAPL (as well as LNAPL in the vadose zone) to volatilization and enhanced aerobic biodegradation with hydraulic LNAPL removal as a secondary remediation objective.
-<onlyinclude>
 *  '''Enhanced LNAPL Recovery (three variations):'''
-**  Water Flooding (including hot water flooding): Water is injected to enhance the LNAPL gradient toward recovery wells.</onlyinclude> Hot water may be injected to reduce LNAPL viscosity and interfacial tension and further enhance LNAPL removal by hydraulic recovery.<onlyinclude>
+**  Water Flooding (including hot water flooding): Water is injected to enhance the LNAPL gradient toward recovery wells.  Hot water may be injected to reduce LNAPL viscosity and interfacial tension and further enhance LNAPL removal by hydraulic recovery.
 **  Surfactant-enhanced Subsurface Remediation (SESR): A surfactant is injected to decrease interfacial tension and increase solubility. LNAPL and water are recovered hydraulically.
 **  Cosolvent Flushing: A solvent is injected to increase LNAPL solubility and mobility. LNAPL and water are recovered hydraulically.
-*  '''''In situ'' Thermal Remediation (four variations):'''</onlyinclude> (See also: [[Thermal Remediation]])<onlyinclude>
+*  '''''In situ'' Thermal Remediation (four variations):''' (See also: [[Thermal Remediation]])
-**  Steam Injection: LNAPL is removed by forcing steam into the aquifer</onlyinclude> to vaporize and solubilize LNAPL, increase LNAPL recovery by reducing the viscosity and interfacial tension of LNAPL, and enhance the LNAPL gradient. Vapors, impacted groundwater, and LNAPL are recovered via vapor extraction and hydraulic recovery.<onlyinclude>
+**  Steam Injection: LNAPL is removed by forcing steam into the aquifer to vaporize and solubilize LNAPL, increase LNAPL recovery by reducing the viscosity and interfacial tension of LNAPL, and enhance the LNAPL gradient. Vapors, impacted groundwater, and LNAPL are recovered via vapor extraction and hydraulic recovery.
-**  Thermal Conduction Heating: Soil is heated using heating elements</onlyinclude> to vaporize and solubilize LNAPL and increase LNAPL recovery by reducing the viscosity and interfacial tension of LNAPL. Vapors, impacted groundwater, and LNAPL are recovered via vapor extraction and hydraulic recovery.<onlyinclude>
+**  Thermal Conduction Heating: Soil is heated using heating elements to vaporize and solubilize LNAPL and increase LNAPL recovery by reducing the viscosity and interfacial tension of LNAPL. Vapors, impacted groundwater, and LNAPL are recovered via vapor extraction and hydraulic recovery.
-**  Electrical Resistance Heating: Electrical current is used to heat soil and groundwater through subsurface electrodes</onlyinclude> to vaporize and solubilize LNAPL and increase LNAPL recovery by reducing the viscosity and interfacial tension of LNAPL. Vapors, impacted groundwater, and LNAPL are recovered via vapor extraction and hydraulic recovery.<onlyinclude>
+**  Electrical Resistance Heating: Electrical current is used to heat soil and groundwater through subsurface electrodes to vaporize and solubilize LNAPL and increase LNAPL recovery by reducing the viscosity and interfacial tension of LNAPL. Vapors, impacted groundwater, and LNAPL are recovered via vapor extraction and hydraulic recovery.
-**  ''In situ'' Smoldering:</onlyinclude> This is an emerging technology with very limited project experience. ''In situ'' smoldering is <onlyinclude>initiated through a short duration, low energy “ignition event.” Combustion is sustained by the addition of air through a well to the target treatment zone.</onlyinclude> The energy of the reacting contaminants is used to pre-heat and initiate combustion of contaminants in adjacent areas, propagating a combustion front through the LNAPL-impacted zone in a self-sustaining manner, provided a sufficient flux of oxygen is supplied.
+**  ''In situ'' Smoldering: This is an emerging technology with very limited project experience. ''In situ'' smoldering is initiated through a short duration, low energy “ignition event.” Combustion is sustained by the addition of air through a well to the target treatment zone. The energy of the reacting contaminants is used to pre-heat and initiate combustion of contaminants in adjacent areas, propagating a combustion front through the LNAPL-impacted zone in a self-sustaining manner, provided a sufficient flux of oxygen is supplied.
-[[File: Farhat1w2Fig2.png | thumb | 350 px | Figure 2.  Air Sparging/Soil vapor extraction system (AS/SVE)<ref name="USEPA 2012">US Environmental Protection Agency (USEPA), 2012. A Citizen’s Guide to Soil Vapor Extraction and Air Sparging, Office of Solid Waste and Emergency Response, U.S. EPA. Document No. EPA 542-F-12-018. [https://www.enviro.wiki/images/c/c4/EPA-2012-A_Citizens_Guide_to_soil_vapor_extraction_and_air_sparging.pdf  Report.pdf]&nbsp;&nbsp;  Also available from: [https://clu-in.org/download/Citizens/a_citizens_guide_to_soil_vapor_extraction_and_air_sparging.pdf  USEPA]</ref>.]]<onlyinclude>
+[[File: Farhat1w2Fig2.png | thumb | 350 px | Figure 2.  Air Sparging/Soil vapor extraction system (AS/SVE)<ref name="USEPA 2012">US Environmental Protection Agency (USEPA), 2012. A Citizen’s Guide to Soil Vapor Extraction and Air Sparging, Office of Solid Waste and Emergency Response, U.S. EPA. Document No. EPA 542-F-12-018. [https://www.enviro.wiki/images/c/c4/EPA-2012-A_Citizens_Guide_to_soil_vapor_extraction_and_air_sparging.pdf  Report.pdf]&nbsp;&nbsp;  Also available from: [https://clu-in.org/download/Citizens/a_citizens_guide_to_soil_vapor_extraction_and_air_sparging.pdf  USEPA]</ref>.]]
-*  '''Air Sparging/Soil Vapor Extraction (AS/SVE):'''  AS injects air into the saturated zone</onlyinclude> to solubilize (enhanced through turbulence), aerobically biodegrade, and volatilize LNAPL constituents from the submerged and overlying portions of the LNAPL body where airflow occurs. <onlyinclude>SVE</onlyinclude> also enhances aerobic biodegradation and volatilization of the LNAPL constituents from the vadose zone and<onlyinclude> collects vapors created by AS</onlyinclude> (Figure 2). AS or SVE can also be used individually if conditions are appropriate. A significant portion of the LNAPL depletion accomplished by AS/SVE is due to enhancement of aerobic biodegradation. LNAPL mass removal in the vadose zone is sustained during SVE because it can draw continuous LNAPL from the saturated zone into the vadose zone via capillary processes (wicking).  (See also: [[Soil Vapor Extraction (SVE)]])
+*  '''Air Sparging/Soil Vapor Extraction (AS/SVE):'''  AS injects air into the saturated zone to solubilize (enhanced through turbulence), aerobically biodegrade, and volatilize LNAPL constituents from the submerged and overlying portions of the LNAPL body where airflow occurs. SVE also enhances aerobic biodegradation and volatilization of the LNAPL constituents from the vadose zone and collects vapors created by AS (Figure 2). AS or SVE can also be used individually if conditions are appropriate. A significant portion of the LNAPL depletion accomplished by AS/SVE is due to enhancement of aerobic biodegradation. LNAPL mass removal in the vadose zone is sustained during SVE because it can draw continuous LNAPL from the saturated zone into the vadose zone via capillary processes (wicking).  (See also: [[Soil Vapor Extraction (SVE)]])
 *  '''Biosparging/Bioventing:'''  Similar processes to AS/SVE, except air/oxygen is injected more slowly with the main goal being stimulation of aerobic biological degradation of LNAPL in the saturated and unsaturated zones. Various configurations are possible including inducing airflow into and through the unsaturated zone by extraction of soil vapors.

@@ Line 37: / Line 37: @@
 Because of these challenges, it is important to understand what LNAPL technologies can and can’t do to address different LNAPL concerns.
 <onlyinclude>
-==LNAPL Technologies==</onlyinclude>
+==LNAPL Technologies==
 [[File: Farhat1w2Fig1.png | thumb | right | 350px | Figure 1.  Dual Pump LNAPL Recovery System (Sale et al. 2018)<ref name="Sale2018"/>.]]
 <onlyinclude>The ITRC (2018)</onlyinclude><ref name="ITRC2018"/><onlyinclude> presented an overview of remediation technologies (summarized below) based upon a survey of the LNAPL team’s experience and knowledge.</onlyinclude> Some are more innovative or have a better record of accomplishment than others.   Note that enhanced aerobic biodegradation is not listed separately because aerobic biodegradation occurs during many of the other technologies including all aeration methods and [[Chemical Oxidation (In Situ - ISCO) | ''In Situ'' Chemical Oxidation (ISCO)]].

@@ Line 76: / Line 76: @@
 *  '''Physical or Hydraulic Containment:'''  Subsurface barriers (e.g., sheet piles, French drains, slurry walls, groundwater extraction, trenches, and permeable absorptive barriers) are constructed to prevent, impede, or divert LNAPL migration. It is generally a mass control technology and does not significantly reduce LNAPL mass unless designed to do so (e.g., oleophilic biobarriers).
-*  '''''In situ'' Soil Mixing (Stabilization):'''  LNAPL is immobilized by reducing the permeability of the LNAPL zone through in situ mixing of amendments (e.g., addition of bentonite clay or cement). In addition to reducing LNAPL mobility, it also reduces the leachability and volatility of the LNAPL constituents.
+*  '''''In situ'' Soil Mixing (Stabilization):'''  LNAPL is immobilized by reducing the permeability of the LNAPL zone through ''in situ'' mixing of amendments (e.g., addition of bentonite clay or cement). In addition to reducing LNAPL mobility, it also reduces the leachability and volatility of the LNAPL constituents.
 The ITRC<ref name="ITRC2018"/> describes what each technology can do with regard to different LNAPL concerns (e.g., dissolved phase plume migration, vapor intrusion, LNAPL body migration, etc.).  A quantitative look at LNAPL remediation performance for one particular concern, dissolved phase hydrocarbon plumes that exceed action levels, is presented below.  (Note this is just one LNAPL concern and remediation performance will be different if a remediation technology is being applied to address a different concern.)

@@ Line 1: / Line 1: @@
-There are a variety of Light Non-Aqueous Phase Liquid (LNAPL) remediation approaches.  This article provides brief summaries of some LNAPL remediation technologies with links for additional information.  Results from performance evaluations are presented.  Finally, the Interstate Technology and Regulatory Council (ITRC) framework for selecting LNAPL remediation technologies is presented.
+There are a variety of Light Non-Aqueous Phase Liquid (LNAPL) remediation approaches.  This article provides brief descriptions of various LNAPL remediation technologies with links for additional information, summarizes performance evaluation results, and presents the Interstate Technology and Regulatory Council (ITRC) framework for selecting LNAPL remediation technologies.
 <div style="float:right;margin:0 0 2em 2em;">__TOC__</div>
 '''Related Articles'''
@@ Line 45: / Line 45: @@
 *  '''Fluid Recovery (4 variations; excludes soil vapor extraction [SVE] or groundwater-only recovery):'''
 **  Skimming: LNAPL is the only fluid removed using a pump or similar continuous mechanical device. There may be small volume of incidental water recovery.
-**  Vacuum Enhanced Skimming: LNAPL and vapor are the fluids removed. LNAPL drawdown via skimming and vacuum induces an LNAPL gradient toward the recovery point. Also referred to as bioslurping or vacuum enhanced fluid recovery (VEFR).
+**  Vacuum Enhanced Skimming: LNAPL and vapor are the phases removed. LNAPL drawdown via skimming and vacuum induces an LNAPL gradient toward the recovery point. Also referred to as bioslurping or vacuum enhanced fluid recovery (VEFR).
 **  Total Liquid Extraction: LNAPL and water are the fluids removed. Drawdown of LNAPL and groundwater induces an LNAPL gradient toward the recovery point. Groundwater drawdown may expose submerged LNAPL thereby increasing LNAPL mobility and recovery rate. Groundwater extraction may also provide hydraulic containment of potentially migrating LNAPL. Also referred to as dual pump liquid extraction (DPLE)<ref name="ITRC2009"> Interstate Technology and Regulatory Council (ITRC), 2009.  Evaluating LNAPL Remedial Technologies for Achieving Project Goals (LNAPL-2). ITRC, LNAPLs Team, Washington, D.C. 157 pp.  [https://www.enviro.wiki/images/7/7a/ITRC-2009a_Evaluating_LNAPL_Rem_Tech.pdf Report.pdf]&nbsp;&nbsp;  Available from:  [https://www.itrcweb.org/GuidanceDocuments/LNAPL-2.pdf   ITRC] </ref> (Figure 1)
-**  Multi-Phase Extraction (MPE): LNAPL, water, and vapor are the fluids removed. LNAPL drawdown, groundwater drawdown, and vacuum induce an LNAPL gradient toward the recovery point. Groundwater drawdown may expose submerged LNAPL thereby increasing the LNAPL recovery rate. Groundwater extraction may also provide hydraulic containment of potentially migrating LNAPL. Also referred to as dual-phase extraction (DPE) or two-phase extraction (TPE)<ref name="USACE1999">US Army Corps of Engineers (USACE), 1999. Engineering and Design: Multi-Phase Extraction, Engineer Manual. USACE, Washington, D.C. Manual No. EM 1110-1-4010, 286 pp. [[Media: USACE_1999-MPEmanual.pdf | Report.pdf]]</ref>. MPE is also often used as a phase-change technology to expose submerged LNAPL (as well as LNAPL in the vadose zone) to volatilization and enhanced aerobic biodegradation with hydraulic LNAPL removal as a secondary remediation objective.
+**  Multi-Phase Extraction (MPE): LNAPL, water, and vapor are the phases removed. LNAPL drawdown, groundwater drawdown, and vacuum induce an LNAPL gradient toward the recovery point. Groundwater drawdown may expose submerged LNAPL thereby increasing the LNAPL recovery rate. Groundwater extraction may also provide hydraulic containment of potentially migrating LNAPL. Also referred to as dual-phase extraction (DPE) or two-phase extraction (TPE)<ref name="USACE1999">US Army Corps of Engineers (USACE), 1999. Engineering and Design: Multi-Phase Extraction, Engineer Manual. USACE, Washington, D.C. Manual No. EM 1110-1-4010, 286 pp. [[Media: USACE_1999-MPEmanual.pdf | Report.pdf]]</ref>. MPE is also often used as a phase-change technology to expose submerged LNAPL (as well as LNAPL in the vadose zone) to volatilization and enhanced aerobic biodegradation with hydraulic LNAPL removal as a secondary remediation objective.
 *  '''Enhanced LNAPL Recovery (three variations):'''
@@ Line 86: / Line 86: @@
 # ISCO,
-# air sparging,
+# Air sparging,
-# mobilizing surfactants,
+# Mobilizing surfactants,
-# solubilizing surfactants,
+# Solubilizing surfactants,
 # LNAPL recovery,
 # Pump and Treat (P&T), and
@@ Line 154: / Line 154: @@
 <blockquote>''Technology selection is a stepwise and linear process for addressing each LNAPL concern; however, remedy selection is seldom linear. The initial focus in technology selection, therefore, should not be when (i.e., in what sequence) each concern is addressed or step is performed, but rather that each is addressed/performed sufficiently. If all concerns are addressed, then the regulating authority can be confident that a complete remedial strategy is being proposed, and the proposing entity can be confident that the proposal is likely to be effective and acceptable to regulators and stakeholders alike. However, some concerns ultimately may take precedence over others and thus dictate the order of technology implementation.''<ref name="ITRC2018"/></blockquote>
-The ITRC LNAPL guidance<ref name="ITRC2018"/> provides a series of detailed tables to help with the general or preliminary screening of technologies based on the LNAPL remedial goal, LNAPL remediation objective, and applicable site conditions.  Detailed technology summaries (provided in Appendix A of the ITRC guidance) are then relied upon for the detailed screening.  After applicable technologies have been identified, a final evaluation is performed, typically based on four to six key factors from the following list of Technology Evaluation Factors:
+The ITRC LNAPL guidance<ref name="ITRC2018"/> provides a series of detailed tables to help with the general or preliminary screening of technologies based on the LNAPL remedial goal, LNAPL remediation objective, and applicable site conditions.  Comprehensive technology summaries (provided in Appendix A of the ITRC guidance) are then relied upon for the detailed screening.  After applicable technologies have been identified, a final evaluation is performed, typically based on four to six key factors from the following list of Technology Evaluation Factors:
 * Remedial timeframe

@@ Line 147: / Line 147: @@
 ==ITRC Remediation Technology Selection Process==
-[[Media:Farhat1w2Fig5.png | thumb | 450 px | Figure 5.  ITRC LNAPL Technology Screening Process<ref name="ITRC2018"/>.]]
+[[File:Farhat1w2Fig5.png |thumb| 450 px | Figure 5.  ITRC LNAPL Technology Screening Process<ref name="ITRC2018"/>.]]
-[[Media:Farhat1w2Fig6.png | thumb | 450 px | Figure 6.  Relationship between LNAPL State, LNAPL Concern, Technology Group, and Recoverability<ref name="ITRC2018"/>.]]
+[[File:Farhat1w2Fig6.png |thumb| 600 px | Figure 6.  Relationship between LNAPL State, LNAPL Concern, Technology Group, and Recoverability<ref name="ITRC2018"/>.]]
 The ITRC (2018) developed a general framework for remedial technology process selection (Figure 5) in which remediation goals are established, remediation objectives are determined (see LNAPL Conceptual Site Models, coming soon), followed by a general screening process, and then a detailed screening. The ITRC observed that: