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| Resource Library > Technology Transfer > Programs and Initiatives |
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The AFCEE, through its Technology Transfer Program, offers an information avenue to help its customers traverse the myriad of choices for applying existing and innovative technologies in the fields of environmental restoration and pollution prevention. The AFCEE Technology Transfer Program has demonstrated cost avoidance and savings in support of site closure, maintenance, and industrial activities through the use of innovative technologies. The Program continues to investigate new challenges to remedial program managers (RPMs), to ensure the proper tools are available to RPMs to address new contaminants of concern, challenging site lithologies, and optimizing environmental technologies to achieve cost savings in a world of dwindling restoration dollars.
There are several technology thrusts and initiatives within the AFCEE Technology Transfer Program. They are highlighted elsewhere on this web site, and several of them are described in this Technologies web page and in the technology-specific pages in much greater detail, in addition to a provision of the many tools (work plans, protocols, guidance documents, software tools, computer models, databases, links, etc.) that have been generated through these efforts. Be sure to explore the other portions of this web site to obtain other helpful information. You may also contact the Technology Transfer Point of Contact for more information or to seek further assistance.
Initiatives and Thrusts
Source Reduction/Removal
A released hydrocarbon may be present in four phases, (1) on the solid phase bound to the soil, (2) in the non-aqueous pliquid phase, (3) in the dissolved phase present in ground water, and (4) as a vapor phase in soil pores. Subsurface phase distrubutions and migration of hydrocarbons are governed by complex physicochemical, biological, and hydrological factors. The removal of solid-phase and non-aqueous liquid phase contaminants may reduce the potential for migration of contaminants.
AFCEE has investigated and validated two hydrocarbon recovery systems. They are bioslurping and bioventing. Bioslurping is a form of vacuum-enhanced pumping. It targets the removal of light non-aqueous phase liquids (LNAPLs) that may accumulate as a layer on top of the water table. Bioventing is a proven technology that provides in situ soil aeration to enhance aerobic biodegradation of petroleum hydrocarbons. Click here to find out more about these proven AFCEE Technology Transfer success stories.
In addition to petroleum hydrocarbon contamination, a significant number of Air Force sites are contaminated with high levels of chlorinated solvents. Because chlorinated solvents are denser than water, they exist as an immiscible phase (a dense non-aqueous phase liquid, or DNAPL) when released to the environment. The subsurface migration of DNAPLs are not controlled by conventional groundwater transport mechanisms (advection, dispersion and diffusion) but by geological structures (e.g., fissures, faults and bedding planes) and by gravity. The heterogeneous nature of the subsurface and the physical characteristics of DNAPLs, make migration very unpredictable and difficult to model. Relatively small spills may possess adequate 'driving force' to migrate downward through permeable drift deposits into fractured and well-bedded sandstone aquifers. DNAPLs will tend to sink below the water table to reach layers of low permeability (e.g., clay lenses, aquitards, and bedrock). They may sit in 'pools', dissolving into the aqueous phase over a long period of time to contribute to long-term groundwater contamination.
Very little guidance exists to describe how source treatment will result in significant reduction in long-term care requirements. The approach within the AFCEE Technology Transfer Program to address DNAPL contamination includes testing, evaluating, and deploying new source characterization tools; evaluating effectiveness of source zone treatment technology; and developing practical technical guidance. There are several efforts within the source zone reduction/removal initiative within the AFCEE Technology Transfer Program.
Enhanced In Situ Anaerobic Bioremediation
The DoD has identified hundreds of sites where groundwater is contaminated with chlorinated aliphatic hydrocarbons (CAHs, commonly referred to as chlorinated solvents), and these represent one of the DoD's largest remediation liabilities. CAHs were often released to the subsurface environment in the form of dense nonaqueous phase liquids (DNAPLs). As a result of their physical and chemical properties, DNAPLs are difficult to remediate once they have migrated into groundwater aquifers.
Enhanced anaerobic bioremediation (EAB) can be an effective method of degrading various forms of chloroethenes, chloroethanes, and chloromethanes dissolved in groundwater. Numerous universities, government entities, and private industries have applied a wide variety of organic substrates to promote anaerobic reductive dechlorination of CAHs to innocuous end products. Research continues on alternate degradation processes (e.g., anaerobic oxidation and abiotic reactions) related to substrate addition, and the ability of anaerobic degradation processes to promote accelerated desorption and degradation of DNAPL in source areas.
EAB can cost-effectively remediate contaminanted sites if (1) the site can be engineered to provide appropriate growth conditions favorable to existing microorganisms, and (2) contaminants are susceptible to enhanced bioremediation (e.g., chlorinated solvents, perchlorate). However, although EAB has been applied at over 600 sites to date, it has yet to gain widespread regulatory acceptance as a proven technology primarily due to lack of consistency in achieving remedial objectives. To further prove the technology AFCEE has generated several successful forms of the technology, including vegetable oil injection, molasses injection, and biobarriers AFCEE has successfully installed and achieved extremely promising results from several systems at numerous Air Force sites. Additional future investigations include investigating abiotic contributions, electron shuttles, and application for emerging contaminants such as perchlorate. Access the AFCEE Enhanced In Situ Bioremediation web page for more information about this initiative as well as available guidance, protocol, work plan, final reports, cost and performance reports, presentations, and other helpful information.
Phytoremediation
Phytoremediation is the use of plants and trees to cleanup contaminated soil and water. Growing plants on a contaminated site as a remediation method is a solar-energy driven passive technique that can be used along with, or in some cases in place of mechanical cleanup methods. Phytoremediation has been used to clean up metals, pesticides, solvents, explosives, crude oil, polyaromatic hydrocarbons, and landfill leachates. Phytoremediation in shallow soils has the advantage of being low cost, low maintenance, potentially highly effective, and generally accepted by stakeholders, and other concerned parties. To date, AFCEE has investigated phytoremediation at 8 sites with an estimated cost avoidance of $7 million, and has generated two guidance documents, "Protocol for Controlling Contaminated Groundwater by Phytostabilization" and "Vegetative Landfill Covers and Phytostabilization."
Natural Attenuation
Natural attenuation, also known as intrinsic remediation, passive bioremediation, and intrinsic bioremediation, depends on physicochemical and biological processes to degrade and dissipate contaminants in soil and groundwater. These natural processes include aerobic and anaerobic biodegradation, dispersion, volatilization, and sorption. Under appropriate site conditions, natural attenuation reduces the potential impact of contaminant release by preventing constituents from being transported to sensitive receptors, or by reducing constituent concentrations. Natural attenuation may also be a finishing option for sites subjected to other remediation techniques.
AFCEE was instrumental in developing the current understanding of natural attenuation. Beginning in the early 1990s AFCEE, with the participation of the US EPA, undertook an extensive field investigation of natural attenuation at petroleum-contaminated Air Force sites. One outcome of this effort was the development of a detailed field protocol for conducting and interpreting natural attenuation studies. Subsequent to this AFCEE undertook a similarly extensive field investigation of natural attenuation at Air Force sites contaminated with chlorinated aliphatic hydrocarbons (CAH), such as trichloroethene. This effort led to the development of a field protocol for conducting natural attenuation studies at chlorinated-contamination sites. AFCEE has also developed and fielded several modeling programs to aid in the evaluation of natural attenuation. For more about these proven AFCEE Technology Transfer success stories, visit our natural attenuation web page and our web page containing links to our software modeling tools.
Off-gas Treatment
Remediation systems, such as bioventing or soil vapor extraction, which require air to penetrate through contaminated media to stimulate biological activity, can lead to uncontrolled emissions of contaminant vapor. In some states, off-gas treatment is required to meet state air-quality standards.
The choice of off-gas treatment depends largely on the characteristics of the contaminant vapor. Fuels are combustible organic compounds that can be treated by either separating organic compounds from the vapor stream or by chemically transforming (combustion/oxidation) the organic into harmless end products. Chlorinated solvents are not easily amenable to transformation approaches because the end products usually include hydrogen chloride, which has corrosive attributes. AFCEE has successfully investigated four approaches to off-gas treatment. These include an internal combustion engine, a regenerative resin system, and flameless thermal oxidizer, and biofiltration. To access more information about off-gas treatment from AFCEE, visit the AFCEE off-gas treatment web page.
Long-term Management/Long-term Optimization (LTM/LTO)
Long-term Management/Long-term Optimization (LTM/LTO) programs are designed to meet one or more of the following goals: (1) to examine the accuracy of the Remedial Investigation/Feasibility Study (RI/FS), ensuring that predictions are as expected with the remedy selected, (2) to provide early warning that an additional Remedial Action (RA) may soon be necessary, (3) to audit contaminant concentration levels at a compliance location, (4) to audit the RA, and (5) to improve remediation methodologies and the quality of subsequent RAs.
Optimizing existing or planned LTM/LTO programs involves reducing the cost of the programs while maintaining or increasing their quality and effectiveness. These programs require extensive data collection and analyses, some of which may have become irrelevant to the objectives of the monitoring program. The cost of irrelevant data collection is compounded by that of processing, management, review, and preparation of the periodic LTM/LTO report.
One form of LTM/LTO is Remedial Process Optimization (RPO). RPO focuses on appropriate technology implementation and operation. Taking into consideration site -specific conditions and the nature and extent of contamination, RPO involves periodic review and optimization of each component of the remedial process. Besides selection of the appropriate technology, a RPO approach reviews the monitoring plan, the cleanup goals, system operation, and data requirements. Under the Technology Transfer Program, AFCEE has developed several tools for RPO and other LTM/LTO approaches. For more information regarding LTM/LTO, visit the AFCEE LTM/LTO web page; you can also visit the AFCEE RPO Outreach Office web page for more information on that subject.
Landfill Covers
The AFCEE Technology Transfer Program supports the development of new concepts regarding the remediation and closure of landfill sites that provide opportunities for improved performance, and cost saving in both remediation and long-term maintenance. A survey of Air Force landfills shows that there are significant differences between Air Force landfills and currently operating commercial landfills and these differences should be considered when designing and implementing remedial actions.
The technology available for landfill remediation is changing. New remediation methods are becoming available and some are now being accepted by regulators. The old notion of entombment and preservation of waste is giving way to new concepts for managing wastes. It is important to understand that new technology must meet the critical goal of landfill remediation which is to protect human health and the environment. Click here to obtain more information about the many tools and documents available on landfill covers and other alternatives from the AFCEE Technology Transfer Program.
Risk-based Approach
The objective of risk-based remediation is to reduce the risk of specific chemicals to human health and/or ecological receptors (i.e., non-domesticated plants and animals). For any chemical to pose a risk, four elements must exist at the site: (1) a source of chemical contamination that exceeds or could generate chemical contamination above health-protective or aesthetic standards; (2) a mechanism of contaminant release; (3) a human or ecological receptor available for chemical contact; and (4) a completed exposure route through which that receptor will contact the chemical.
If any one of these four elements is absent at a site, there is no current risk. The reduction or elimination of risk can be accomplished by limiting or removing any one of these four elements from the site. The goal of risk-based remediation approach is to find the most cost-effective method of reducing current and future potential risk by combining three risk-reduction techniques: (1) contaminant source reduction; (2) contaminant migration control; and (3) receptor restriction.
The AFCEE Technology Transfer Program has produced several tools to aid in approaching risk-based cleanup efforts. Click here for more information.
Site Characterization and Monitoring
The AFCEE Technology Transfer Program has involved extensively in the development, investigation, demonstration, and validation of various technologies and tools to optimize site characterization and monitoring efforts for the RPM. Such efforts included the development of a small, transportable direct push technology (DPT) platform for real-time screening tool deployment, and the development of innovativesubsurface sensors for small platform and large cone penetrometer (CPT) trucks. AFCEE has also developed and field tested the HyperLogger, Haloprobe and REMPI tools. The HyperLogger provides sensitive and rapid delineation and identification of POLs, while the Haloprobe provides subsurface detection of chlorinated solvents. REMPI provides sensitive and specific detection of fugitive BTEX (leak detection of pipelines, flanges, LUSTs), and the REMPI - MIP provides sensitive and specific detection of dissolved phase POLs (BTEX). Contact the Technology Transfer Point of Contact for more information on the DPT and CPT tools and initiatives of the AFCEE Technology Transfer Program.
Another initiative within the AFCEE Technology Transfer Program is the promotion of rapid site characterization. The first such effort was conducted in Moron, Spain, in the summer of 2001. 19 sites were assessed in 28 days, in 153 laser induced fluorescence fuel sensor pushes. Characterization was conducted using a membrane interface probe to delineate TCE plume impacting a water production well, and 65 direct push monitoring wells were installed. AFCEE is actively pursuing expanding rapid site characterization throughout the Air Force as significant cost savings and optimized characterization efforts can be achieved. Contact the Technology Transfer Point of Contact for more information on the rapid site characterization initiative of the AFCEE Technology Transfer Program
AFCEE has also been instrumental in the development and successful deployment of the passive diffusion bag sampler technology. The diffusion sampler technology utilizes a deionized water-filled, low-density polyethylene diffusion membrane to collect water samples from groundwater monitoring wells. VOCs in the groundwater diffuse into the deionized water contained in the sampling bag. Chemical equilibrium between the groundwater and sampler water typically occurs within 14 days, providing a water sample that is representative of VOC concentrations in the well water. Diffusion samplers can be used to easily and inexpensively obtain groundwater samples for VOCs in monitoring wells. When used appropriately, representative groundwater samples can be obtained without well purging to identify temporal changes in well water chemistry. Diffusion samplers provide the potential for significant cost savings at facilities where long-term monitoring of groundwater is being conducted. In particular the diffusion sampler technology can potentially reduce or eliminate costs associated with conventional well purging and micropurging, including labor, equipment, and purge water disposal. Click here for a wealth of information regarding the passive diffusion bag sampler technology.
Emerging Contaminants
Emerging Contaminants (EC) are chemicals or materials that are characterized by a perceived or real threat to human health or environment and a lack of published health standards or a standard that is evolving or being reevaluated. A contaminant may be "emerging" because of the discovery of a new source, a new pathway to humans, or a new detection method or technology. This means that contaminants that are already known, have toxicity values, or are already regulated may still be considered emerging because the science has evolved to the point where the regulatory climate can be expected to change. AFCEE Technology Transfer has compiled information and resources on several emerging contaminants: perchlorate, naphthalene, and 1,4-Dioxane. Perchlorate salts are man-made compounds used as combustion accelerants, predominantly in solid-fueled rockets and missiles. Perchlorate salts are also found to a lesser extent in some munitions, pyrotechnics, and are even thought to exist naturally. Perchlorate contamination has been identified in several locations in the United States both on private and DOD properties. In 1997, the ability to detect perchlorate in lower concentrations in the environment was enhanced when sampling protocols were developed which allowed it to be detected at 4 parts per billion (ppb). Several technologies have been developed to clean up perchlorate contamination. Additional perchlorate information is located at the AFCEE Technology Transfer Emerging Contaminants web page for perchlorate.
1,4-Dioxane is a colorless, flammable liquid with a faint, pleasant odor, the synthetic industrial chemical is used as a solvent. 1,4-Dioxane was produced in large quantities throughout the 1970s, 1980s, and into the early 1990s it was used as a stabilizer to prevent degradation of chlorinated industrial solvents, primarily 1,1,1-trichloroethane. Improved analytical detection capabilities and enhanced sampling protocols have been developed for 1,4-Dioxane. While formal water quality standards and cleanup levels have not yet been promulgated at the federal level, at least 18 states and the EPA have established regulatory guidelines, action levels, and remediation targets that generally fall below 1 ppb. Additional information can be found at the AFCEE Technology Transfer Emerging Contaminant web page for 1,4-Dioxane.
Naphthalene is a white solid or a liquid that occurs naturally in fossil fuels and is used in a broad array of commercial products including jet fuel, pharmaceuticals, textile chemicals, lubricants, explosives, plasticizers, insect repellents, mothballs, dyes, resins, leather tanning agents, and pesticides. Naphthalene is released by combustion of fossil fuels and organic materials such as wood and tobacco. Naphthalene contamination is typically released to the environment as a result of emanating from hazardous waste sites, typically fuel spills and landfills. Naphthalene was added to the emerging contaminant list due to inhalation studies in mice and rats conducted by the National Toxicology Program in 2000. As a result, EPA may lower regulator levels. A reduction in cleanup standards could create challenges for the Air Force and DOD including sites already closed under older, less rigorous standards. Additional information can be found at the AFCEE Technology Transfer Emerging Contaminant web page for Naphthalene.
Technology Transfer Workshop
AFCEE has been proud to host the Technology Transfer Workshops since 1991. Held nearly annually, the workshops have provided hundreds of attendees with the tools to support the DOD readiness mission through environmental stewardship. The valuable classroom experience provided through the workshops offer the latest knowledge and skills necessary to achieve site closure and property transfer.
Covering more than a decade, the AFCEE Technology Transfer Workshops have continued to grow in both attendance and technical offerings, expanding from originally two topics and 100 attendees in 1991, to nearly 100 technical presentations given in 15 concurrent sessions held over three days, with nearly 400 attending in 2003. Past workshop highlights have included short courses (including hands-on field demonstrations and computer classes), open panel discussions, exhibit halls, receptions, and multiple opportunities for breakout sessions. Workshop attendees have received professional development hours for attending the workshop, as well as for participating in the optional short courses. In addition, through the workshops, AFCEE has recognized the outstanding accomplishments and efforts of the environmental professionals and interested parties who have embodied the spirit of teamwork while acting as stewards of the environment.
The AFCEE Technology Transfer Workshops provide an open forum for exchanging ideas, success stories, case histories, and technologies related to environmental cleanup and site closure. Through open communication, these workshops have succeeded in uniting government, academia, industry, and AFCEE Toolbox Contractors in a combined effort to implement essential site cleanup and closure objectives. Visit the Technology Transfer Workshop website for more information.
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