5
Technology Overview

The Navy requested an update of previous reviews of innovative technologies for cleanup of groundwater, soils, and sediment (NRC 1994, 1997a, 1999a, 2000). This chapter discusses a variety of innovative technologies the Navy might consider during adaptive site management (ASM), for example, for initial remedy selection, as replacements for existing remedies that have proved to be unsuccessful, or as additions to current remedies to better achieve cleanup goals or reduce cleanup time. Because the Navy defined sediment contamination and solvents and metals in soil and groundwater as its most pressing current problems, the focus is on these types of contamination and on applicable remedial technologies, including the concept of treatment trains designed to meet multiple goals for multiple contaminants. The emphasis is on those technologies showing the greatest promise, particularly those technologies being developed and evaluated by the Department of Defense (DoD) and by the U.S. Environmental Protection Agency (EPA) and its Technology Innovation Office in association with the Federal Remediation Technologies Roundtable (FRTR). Although petroleum hydrocarbon sites remain a significant problem because of their sheer number (as discussed in Chapter 1), they are not the focus of this chapter at the request of the Navy and because their cleanup is generally considered to be well understood.

Both in situ and ex situ technologies can be identified according to applicable contaminant groups. Using the FRTR grouping of contaminants (see Table 1-1), eight contaminants groups—halogenated and non-halogenated volatile organic compounds (VOCs), halogenated and non-halogenated semivolatile organic compounds (SVOCs), fuels, inorganics, radionuclides, and explosives—can be defined and linked to the treatment technologies listed in Table 5-1 in terms of both in situ and ex situ procedures. Contaminants and technologies germane to soils, sediments,



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5 Technology Overview The Navy requested an update of previous reviews of innovative technologies for cleanup of groundwater, soils, and sediment (NRC 1994, 1997a, 1999a, 2000). This chapter discusses a variety of innovative technologies the Navy might consider during adaptive site management (ASM), for example, for initial remedy selection, as replacements for existing remedies that have proved to be unsuccessful, or as additions to current remedies to better achieve cleanup goals or reduce cleanup time. Because the Navy defined sediment contamination and solvents and metals in soil and groundwater as its most pressing current problems, the focus is on these types of contamination and on applicable remedial technologies, including the concept of treatment trains designed to meet multiple goals for multiple contaminants. The emphasis is on those technologies showing the greatest promise, particularly those technologies being developed and evaluated by the Department of Defense (DoD) and by the U.S. Environmental Protection Agency (EPA) and its Technology Innovation Office in association with the Federal Remediation Technologies Roundtable (FRTR). Although petroleum hydrocarbon sites remain a significant problem because of their sheer number (as discussed in Chapter 1), they are not the focus of this chapter at the request of the Navy and because their cleanup is generally considered to be well understood. Both in situ and ex situ technologies can be identified according to applicable contaminant groups. Using the FRTR grouping of contaminants (see Table 1-1), eight contaminants groups—halogenated and non-halogenated volatile organic compounds (VOCs), halogenated and non-halogenated semivolatile organic compounds (SVOCs), fuels, inorganics, radionuclides, and explosives—can be defined and linked to the treatment technologies listed in Table 5-1 in terms of both in situ and ex situ procedures. Contaminants and technologies germane to soils, sediments,

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TABLE 5-1 Primary Treatment Technologies In Situ Soil and Sediment Ex Situ Soil and Sediment In Situ Groundwater Ex Situ Groundwater Biosparging Bioventing Bioremediation Capping Chemical Reduction/Oxidation Dual-Phase Extraction Dynamic Underground Stripping Electrokinetics Hot Air Injection Heating Phytoremediation Soil Flushing (in situ) Soil Vapor Extraction Solidification/ Stabilization Steam Extraction Thermally Enhanced Recovery (e.g., EM, in situ RF, ISTD) Vitrification Bioremediation— Composting Bioremediation— Land Treatment Bioremediation— Slurry Phase Chemical Reduction/Oxidation Contained Recovery of Oily Waste Critical Fluid Extraction Cyanide Oxidation Dehalogenation Hydraulic Dredging Incineration (offsite) Incineration (onsite) Landfill Disposal Mechanical Dredging Physical Separation Plasma High-temperature Metals Recovery Pyrolysis Solar Detoxification Soil Washing Solidification/ Stabilization Solvent Extraction Thermal Desorption Vitrification Aeration Air Sparging Bioremediation Bioslurping Chemical Reduction/Oxidation Circulating Wells Cosolvent Flushing Dual-Phase Extraction Dynamic Underground Stripping Electrokinetics Hot Water/Steam Flushing/Stripping Monitored Natural Attenuation Permeable Reactive Barrier Phytoremediation Surfactants/Surfactant Flushing Vertical Barrier Wall Free Product Recovery Pump and Treat with: Air Stripping Bioreactors Carbon Adsorption Chemical Reduction/Oxidation Chemical Treatment Distillation Electrochemical Treatment Filtration Precipitation Reverse Osmosis Solar Detoxification Solvent Extraction Supercritical Water Oxidation UV/Oxidation   SOURCE: Adapted from EPA (1997a).

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and groundwater can be further categorized according to the purpose of the technology and its relative maturity. Accordingly, as indicated in Table 5-2, screening of potential technologies can be facilitated to assist remedial project managers (RPMs) in selecting a remedial alternative. Each technology is defined in a glossary at the end of this chapter. Key reference information useful for identifying and selecting technologies and combinations of technologies responsive to cleanup needs has been consolidated into a matrix published elsewhere (EPA, 1997a; http://www.frtr.gov). Other sources of information include technology-specific fact sheets produced by a joint effort between the Department of Energy (DOE) and the Air Force Base Conversion Agency (as well as those from other federal agencies). The objective of these fact sheets is to provide RPMs with information on optimizing cleanup technologies, on presenting multiple lines of evidence about remedy performance, on preparing five-year reviews, on operating remedy demonstrations, and on communicating progress to the public. The FRTR website maintains a database of many remediation technologies, their applications, conditions of use, performance data, and cost (although it is not comprehensive). This database would be even more useful if universities, states, and the private sector were encouraged to submit additional information where appropriate. The lack of a central, comprehensive database is likely to hamper the data analysis exercises (see Chapter 3) that characterize full-scale ASM. In addition, federal facility database systems are aligned to measure progress of the cleanup process (see Figures 1-1 and 1-2) versus measuring cleanup performance—an approach to data collection and analysis that will need to shift in order for ASM to be successfully implemented. Although site conditions and contaminant sources limit the selection of applicable treatment technologies, most sites can be remediated by three primary strategies—destruction or alteration of contaminants, extraction or separation of contaminants from environmental media, and immobilization of contaminants. Currently, destruction technologies include both in situ and ex situ thermal, biological, and chemical methods. Extraction and separation technologies include thermal desorption, soil washing, solvent and vapor extraction for soils and sediments, and phase separation, adsorption, stripping, and/or ion exchange for groundwater. Immobilization technologies include stabilization, solidification, and containment. Generally, no single technology can remediate an entire site, and the use of treatment trains, sometimes combining in situ and ex situ techniques, is common, as discussed subsequently. The main advantage of in situ treatment is that it allows remediation

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to occur without costly removal of the contaminant source. However, in situ treatment generally requires more time, and there is less certainty about attaining cleanup goals in terms of the extent and uniformity of treatment because of the usual heterogeneity of the source location and problems with treatment verification. In contrast to in situ treatment, the main advantage of ex situ treatment is that it generally requires shorter time periods to complete, and there is more certainty about the extent and uniformity of treatment. However, ex situ treatment incurs costly source excavation/removal and possible permitting and exposure implications. The control and proper disposition of emissions and residuals from ex situ treatment are important considerations that require compliance with permit conditions and the application of best management practices associated with each technology or combination of technologies. It should be noted that disposal actions may also be necessary for such in situ technologies as permeable reactive barriers and phytoremediation. Further discussion of this issue for individual technologies can be found in the references provided in Table 5-2. Beyond considering the potential advantages and disadvantages of in situ and ex situ technologies, an important consideration in the evaluation of a remedy is the physical/chemical properties and the behavior of the contaminant and its source. For instance, subsurface contamination by nonhalogenated or halogenated VOCs potentially exists in four phases: (1) as vapors in the unsaturated zone, (2) as compounds sorbed on soil particles in both saturated and unsaturated zones, (3) as contaminants dissolved into pore water according to their solubility in both saturated and unsaturated zones, and (4) as a nonaqueous phase liquid (NAPL). The preferred remediation may involve a treatment train approach (e.g., air sparging/soil vapor extraction, liquid-phase carbon adsorption, and catalytic oxidation for nonhalogenated VOCs, or groundwater pumping, activated carbon adsorption with adsorbate reinjection, and offsite disposal of spent activated carbon for halogenated VOCs). In the case of soils or sediments, vapor extraction, thermal desorption, and incineration exemplify a corresponding treatment train. A similar scenario could be developed for nonhalogenated or halogenated SVOCs. They can occur in the subsurface as vapors in the saturated zone, as contaminants sorbed or partitioned onto the soil or aquifer material in both the saturated and unsaturated zones or on sediments, as contaminants dissolved into pore water in both saturated and unsaturated zones, and as NAPLs. Common ex situ treatment technologies for SVOCs in groundwater include carbon adsorption and UV oxidation. In

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TABLE 5-2 Candidate Technologies for Soil, Sediment, and Groundwater Remediation Technologya Purposeb Target Contaminantsc a b c d e f a b c d e f In situSoil and Sediment Remediation Bioventing X   X   X   Capping   X   X   X X X X Chemical oxidation/reduction X   X   X X   X In situ heating X   X   X   X X X   Phytoremediation X   X   X X X X   X Soil flushing X   X   X X X   X Soil vapor extraction X   X   X X X   X   Vitrification   X   X   X X X X   X Ex SituSoil and Sediment Remediation Composting X           X X   X   Confined aquatic disposal   X X   X X X X Hydraulic dredging X     X X X X Incineration X     X X X X X   Landfills X X X X X X X   X Land treatment X X   X X   X   Mechanical dredging X     X X X X Slurry-phase bioremediation X X X X X X   X   Soil washing X   X X   X X X X Solidification/stabilization   X   X   X Thermal desorption X   X   X X X X X X   Groundwater Remediation Air sparging X X   X   X X X   X   Bioremediation X X X X X   X   X Bioslurping X   X X   X X X Circulating wells   X X X X X   X Cosolvents and surfactants X   X X   X X X Dual-phase extraction X X X X X X   X Dynamic underground stripping X X X X   X X X Chemical oxidation/reduction   X X   X X X X X X Natural attenuation   X X   X   X   X   Permeable reactive barriers   X X X X X X X   X Phytoremediation X X X     X X X X   X Pump-and-treat X X     X X X X X   Steam flushing X   X X X X X X   X Vertical barrier walls   X   X   X X X X X X aSee Glossary at end of this chapter b(a) Source conversion/removal, (b) plume remediation, (c) containment, (d) remediation enhancement, (e) isolation, (f) pretreatment c(a) Nonhalogenated VOCs, (b) halogenated VOCs, (c) nonhalogenated SVOCs, (d) halogenated SVOCs, (e) fuels, (f) inorganics, (g) radionuclides, (h) explosives d(a) Emerging, (b) innovative, (c) established/conventional SOURCES: Adapted from FRTR (1997, 1998).

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  Maturityd Relevant References g h a b c   X AAEE, 1995, 1997; FRTR, 1998 X   X EPA, 1994; Evanko and Dzombak, 1997; NRC, 1997b, 1999a; EPRI, 1999; McLellan and Hopman, 2000   X   NRC, 1997a; EPA, 1998a   X   Fountain, 1998; FRTR, 1998   X   X   Schnoor, 1998; Fiorenze et al., 2000   X   NRC, 1999a   X AAEE, 1997; FRTR, 1998; NRC, 1999a X   X AAEE, 1997; Evanko and Dzombak, 1997; NRC, 1999a   X   X AAEE, 1995, 1997 X   X   EPA, 1994; NRC, 1997b; EPRI, 1999; McLellan and Hopman, 2000 X   X EPA, 1994; NRC, 1997b; EPRI, 1999; McLellan and Hopman, 2000   X   X AAEE, 1994, 1997; FRTR, 1998 X   X AAEE, 1994, 1997; FRTR, 1998   X AAEE, 1995, 1997; FRTR, 1998 X   X EPA, 1994; NRC, 1997b; EPRI, 1999; McLellan and Hopman, 2000   X   X AAEE, 1995, 1997   X   X AAEE, 1993, 1997; FRTR, 1998; NRC, 1999a X   X AAEE, 1994, 1997; Evanko and Dzombak, 1997   X   X AAEE, 1993, 1997; FRTR, 1998     X Miller, 1996a; NRC, 1999a X   AAEE, 1995, 1997; FRTR, 1998; NRC, 2000   X Miller, 1996b X   Miller and Roote, 1997 X   Jafvert, 1996 X   AAEE, 1997 X   Fountain, 1998; Balshaw-Biddle et al., 2000; NRC, 1999a X   X   EPA, 1998a; NRC, 1999a     X   NRC, 2000 X   X Vidic and Pohland, 1996; EPA, 1998b X   X   EPA, 1999e; Schnoor, 1998; Schnoor, 2002     X FRTR, 1998; NRC, 1999a X Fountain, 1998; NRC 1999a X NRC, 1999a

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soil and sediment, biodegradation, incineration, and excavation with off-site disposal are typical. Associated treatment trains may involve thermally enhanced soil vapor extraction followed by in situ bioremediation for nonhalogenated SVOCs, and excavation, ex situ dehalogenation, soil washing/dewatering and land application for halogenated SVOCs. Inorganic contaminants such as metals may be found in the elemental form, but more often exist as salts mixed in soil or sediment. The fate of metals depends on their physical and chemical properties, the associated waste matrix, and the environmental phase within which they reside. The most common reservoirs for metals are soil and sediment, and the most common treatment technologies include solidification/stabilization, excavation and offsite disposal, and extraction. Depending upon solubility and mobilization potential, metals may also exist in groundwater, and are most frequently treated by ex situ precipitation, filtration, and ion exchange, although in situ treatment by oxidation/reduction and vitrification has occurred. A representative treatment train may be the combination of electrokinetics and phytoremediation. OPTIMIZATION OF REMEDIES Before discussing innovative technologies, it is worthwhile to consider the optimization of existing remedies to make them more efficient and effective. This process can utilize data and information from both routine monitoring conducted during remedy implementation as well as from evaluation and experimentation efforts to better define the site conditions. Periodically reevaluating the entire remedial design to determine whether it should be adjusted is critical because the remedial system is dynamic and will lead to changes in in situ conditions as the remedy is being implemented. As one would expect, optimization is more developed for technologies that have been in use for longer periods, like pump-and-treat. Experiential Optimization As discussed in Chapter 2, the term “optimization” is used here to mean any adjustment in a single remedy to make it more efficient or cost-effective to implement. To distinguish it from mathematical optimization, the report further defines “experiential optimization” to mean remedy adjustments such as eliminating redundancy, replacing over-

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designed components with appropriately sized ones, or relocating or adding some components. In this approach, the technical staff responsible for operation of the remedial system evaluates all components of system design and determines, using engineering judgment, whether any components are redundant, overdesigned, or poorly located and whether additional components are needed. Table 5-3 summarizes examples of experiential optimization for a variety of remedial systems, including soil vapor extraction, air sparging, bioventing, bioslurping, in situ chemical oxidation, reactive permeable barriers, light nonaqueous phase liquid (LNAPL) free product recovery, dense nonaqueous phase liquid (DNAPL) removal and containment, groundwater extraction for hydraulic containment, groundwater extraction for mass removal, and groundwater monitoring. The table entries specifically address optimizing existing remedies and do not include changes to alternate remedies. Additional detail can be found in NAVFAC (2001). These examples demonstrate that a good deal of engineering judgment and expertise are required to implement the suggested schemes. Seventeen case studies mentioning the use of optimization in revising cleanup strategies can be found at the FRTR website (http://www.frtr.gov), although information is not provided on how the optimization was carried out. Mathematical Optimization In the peer-reviewed, archival literature, optimization of a remedial scheme is defined more restrictively to mean mathematical simulation of subsurface fluid flow and/or transport coupled with a linear, nonlinear, or dynamic programming algorithm to predict an optimal configuration or management of remedial system components. Formal mathematical optimization of any remedial system is theoretically possible but in practice has principally been applied to pump-and-treat systems. EPA has recently begun to promote the use of formal mathematical optimization coupled with groundwater modeling for pump-and-treat applications as a potential means to save funds and energy (EPA, 1999a). EPA (1999a) presents a screening model that allows a user to make a rapid determination of whether additional expenditure on a mathematical optimization is worthwhile. In cases where many wells are pumping at a significant rate, where an optimal strategy is not obvious, or where the cost of additional wells is insignificant in comparison to the total amount currently being expended on pumping/energy costs, the screening model will usually indicate that an optimization exercise is worth pursuing. In a

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second volume (EPA, 1999b), EPA provides details of how mathematical optimization of a groundwater pump-and-treat situation can be accomplished. The user of the available software should have access to or should be able to construct a groundwater model of the site, and in addition be able to understand and implement the optimization algorithms suggested by EPA. The level of technical competence of the user is presumed to be relatively high. Typically, pump-and-treat systems are designed based on experience and are adapted to site-specific conditions by carrying out field-scale pilot tests. To assist in the design process, users can use 2- or 3-dimensional numerical groundwater models (e.g., MODFLOW; McDonald and Harbaugh, 1996) to predict groundwater flow paths and hydraulic head distributions at a field site in response to imposed injection or withdrawal stresses, given that site lithology is adequately characterized in terms of spatially varying soil and rock permeabilities. This allows the user to answer questions regarding the number of wells to install and the effects of well placement and pumping rates on the movement of water through the saturated zone. It is possible to find an efficient design by simulating a number of combinations of well numbers, well placement, and injection or withdrawal rates to achieve either desired hydraulic containment or water removal. However, the best design may not be found by such an iterative procedure. There are many possible combinations of design parameters, and identification of a best set of choices for test simulations may not be readily apparent for heterogeneous soils and complicated site boundary conditions. A more advanced level of design technology that builds on the numerical simulation approach is formal optimization of the design variables, where the best combination is found by mathematical techniques used in the field of operations research (e.g., Bradley et al., 1977; Gill et al., 1981). To optimize pump-and-treat design, mathematical programming algorithms can be coupled with a 2- or 3-dimensional groundwater flow model defining the physical system to determine the optimal set of design parameters for achieving pumping or injection objectives. This approach is the topic of EPA’s recent set of reports (EPA, 1999a,b) and is also the subject of textbooks written within the last decade (e.g., Gorelick et al., 1993; Ahlfeld and Mulligan, 2000). Optimization as a formal mathematical methodology that can be used to improve system performance has been in use for some time. Indeed, a literature review reveals that the concept of coupling simulation and optimization models dates back to 1958 (Lee and Aronofsky, 1958) and has been applied in the areas of petroleum and gas production, water supply,

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TABLE 5-3 Summary of Experiential System Optimization of Certain Remedies Technology Component Evaluated for Optimization Recommended Action Justification Soil Vapor Extraction Characterization of subsurface heterogeneity Check for level of detail of characterization Improved detail will aid in better placement of extraction well screens 3D distribution of vapor monitoring probes Check for adequate number of vapor monitoring points Improved placement/numbers will aid in determining adequacy of (1) volume of influence of vacuum system and (2) air flow velocities Flow rates at extraction wells Determine mass removal from each well; decrease flow from unproductive wells and increase flow to more contaminated areas Improve distribution of total energy used for vacuum application Continued high contaminant concentration in vapor Check for unidentified or uncontrolled source areas Presence of continuing source area will extend cleanup times Economics of aboveground vapor treatment system Check treatment efficiency Lower vapor concentrations may cause change in existing treatment efficiency; switching of treatment technology as vapor concentrations get lower could generate cost savings

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Technology Component Evaluated for Optimization Recommended Action Justification Soil Vapor Extraction (con’t.) Location/activity of extraction wells Conduct equilibrium tests by shutting off all wells for 3– 6 weeks Rebounding will occur in hot spots; focus additional contaminant removal on these locations   Vertical location of extraction intervals Vertical profile testing to determine air flow rates and contaminant concentration with depth Determine location of unproductive screened intervals that can be packed off; also want to avoid extracting water from wells that are too close to water table Air Sparging Zone of influence Check for design zone of influence. If not being achieved, increase air flow to injection wells or install additional wells outside current zone of influence; evaluate system for short-circuiting Design zone of influence needs to be achieved to attain cleanup goals   Increasingly high injection pressures required to maintain flow Check wells for plugging; redevelop or replace affected wells Cleanup will not be achieved or will be delayed if injection wells are plugged.   Control of sparging vapors May need to install SVE system Need to keep sparging vapors from migrating to undesirable areas

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shore, island, or land-based confined disposal facilities and enclosing with a cap to provide isolation. Cosolvents and surfactants. Mobilization or solubilization of NAPLs or sorbed contaminants for facilitated removal after injection and flushing of cosolvents or surfactants into the vadose and saturated zones. Dual-phase extraction. Use of a screened vertical well with or without a drop tube under applied vacuum to extract contaminated vapor and both aqueous and nonaqueous liquid above and below the water table, possibly augmented with air injection. Dynamic underground stripping. Combination of steam injection and electrical heating for vacuum extraction of nonaqueous phase liquid contaminants from the subsurface. Electrokinetics. In situ process that separates and extracts inorganic and organic contaminants from saturated and unsaturated soil, sediments, and groundwater under the influence of an imposed electrical field. Incineration. Ex situ thermal process primarily for the destruction or removal of organic compounds from contaminated matrices. Hydraulic dredging. Employing centrifugal pumps to draw up sediment in a liquid slurry form for transfer through a pipeline to a placement site. In situ heating. Raising the temperature of soils by electrical resistance, microwave, and/or radio frequency heating to increase volatility of contaminants and to form steam for vapor-phase transport. Landfill disposal. Placing contaminated materials, with or without pretreatment, in or on the land with liners and covers or caps for containment. Land treatment. Managed treatment and disposal involving tillage of contaminated materials into the surface soil to allow natural assimilation for conversion and containment. Mechanical dredging. Using bucket-like equipment to scoop up sediment by mechanical force to minimize sediment dispersion and other

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effects on sediment properties prior to transfer to the placement site. Natural attenuation. In situ reduction in mass or concentration of contaminants in groundwater, soil, or surface waters from naturally occurring physical, chemical, and biological processes. Permeable reactive barriers. Emplacement of reactive materials in a subsurface structure designed to intercept a contaminant plume, provide flow through the reactive media, and transform contaminants. Phytoremediation. Use of natural or engineered vegetation for in situ plant uptake and containment of contaminated soils, sediments, and water. Pump-and-treat. Use of a series of wells to pump large amounts of contaminated groundwater to the surface for treatment before ultimate surface discharge or reinjection. Slurry phase bioremediation. Biological treatment of contaminated solids and groundwater in suspended growth bioreactors. Soil flushing. In situ soil treatment of contaminants using chemical amendments and fluid pumping to mobilize and recover contaminants. Soil vapor extraction. Use of induced air flow through the unsaturated zone to vacuum-remove volatile compounds from soil in the vapor phase with subsequent treatment and discharge to the atmosphere. Soil washing. Ex situ, water-based process employing chemical and physical extraction and separation to remove contaminants from excavated soil. Solidification/Stabilization. Reduction of hazard by converting contaminants into less soluble, mobile, or toxic forms using chemical, physical, and/or thermal processes. Steam flushing. Injection of steam into the saturated and unsaturated zones to mobilize and volatilize contaminants before recovery through extraction wells and ex situ treatment. Thermal desorption. Direct or indirect ex situ use of heat to physi-

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cally separate and transfer contaminants from soils and sediments before subsequent collection and treatment. Vertical barrier wall. Isolation of contaminant source from flowing groundwater with confinement trenches, grouts, or sheet piling to reduce risk and enhance opportunities for remediation. Vitrification. Application of electrical heating to elevate temperature sufficiently to melt the soil and form a glass upon cooling for extraction/destruction and containment of contaminants. REFERENCES Ahlfeld, D. P., and A. E. Mulligan. 2000. Optimal management of flow in groundwater systems. Academic Press. Air Force. 1997. Design guidance for application of permeable reactive barriers to remediate dissolved chlorinated solvents. Publication No. DG 1110-345-117. Prepared by Battelle for the U. S. Air Force. Air Force. 2001. Final remedial process optimization handbook. Prepared for the Air Force Center for Environmental Excellence, Technology Transfer Division, Brooks Air Force Base, San Antonio, Texas, and Defense Logistics Agency, Environmental Safety Office, Fort Belvoir, VA. American Academy of Environmental Engineers (AAEE), Innovative Site Remediation Technology, W. C. Anderson (ed.). Vol. 1 Bioremediation, 1995, ISBN 1-883767-01-6 Vol. 2 Chemical Treatment, 1994, ISBN 1-883767-02-4 Vol. 3 Soil Washing/Soil Flushing, 1993, ISBN 1-883767-03-2 Vol. 4 Stabilization/Solidification, 1994, ISBN 1-883767-04-0 Vol. 5 Solvent/Chemical Extraction, 1994, ISBN 1-883767-05-9 Vol. 6 Thermal Desorption, 1993, ISBN 1-883767-06-7 Vol. 7 Thermal Destruction, 1994, ISBN 1-883767-07-5 Vol. 8 Vacuum Vapor Extraction, 1994, ISBN 1-883767-08-3 American Academy of Environmental Engineers (AAEE), Innovative Site Remediation Technology (Design & Application), W. C. Anderson (ed.). Vol. 1 Bioremediation, 1997, ISBN 1-883767-17-2 Vol. 2 Chemical Treatment, 1997, ISBN 1-883767-18-0 Vol. 3 Liquid Extraction Technologies; Soil Washing, Soil Flushing, Solvent/Chemical, 1997, ISBN 1-883767-19-9 Vol. 4 Stabilization/Solidification, 1997, ISBN 1-883767-20-2 Vol. 5 Thermal Desorption, 1997, ISBN 1-883767-21-0 Vol. 6 Thermal Destruction, 1997, ISBN 1-883767-22-9 Vol. 7 Vapor Extraction and Air Sparging, 1997, 1-883767-23-7

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