Innovations in Ground Water and Soil Cleanup From Concept to Commercialization (1997) / Chapter Skim
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5 TESTING REMEDIATION TECHNOLOGIES
5 TESTING REMEDIATION TECHNOLOGIES
Pages 201-251
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From page 201... ...
Lacking performance data collected according to a standard protocol, clients may hesitate to choose an innovative remediation technology because of the uncertainty in how the innovative technology will perform in comparison to a conventional technology. The types of data collected for evaluating remediation technology performance vary widely and are typically determined by the preferences of the consultant responsible for selecting the technology, the client, and the regulators overseeing remediation at the contaminated site.
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From page 202... ...
In 1995, the Federal Remediation Technologies Roundtable, a group of lead agency representatives involved in site remediation, issued guidelines for the collection of remediation cost and performance data at federal facilities (Federal Remediation Technologies Roundtable, 1995~. Nevertheless, no standard process exists for data collection and reporting at privately owned contaminated sites, and the degree to which the Federal Remediation Technologies Roundtable guidelines are applied at federal facilities is unclear.
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From page 203... ...
Direct measurements showing decreases in one or more of these parameters are essential for proving technology performance, but they are not sufficient to prove that the technology was responsible for the observed decrease in contamination. For example, contaminant concentrations in ground water may decrease for a variety of reasons, including sorption of contaminants by soil or aquifer solids, dilution due to natural mixing with uncontaminated ground water, biodegradation by native soil microbes, or chemical reactions with substances naturally present in the subsurface.
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From page 204... ...
Which measure is appropriate depends on the remediation end points that the technology is designed to achieve. Contaminant concentrations in the field following application of a remediation technology are readily determined by analyzing ground water samples from monitoring wells and soil samples from soil cores according to standard procedures.
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From page 205... ...
For stabilization and containment technologies, effects on contaminant concentration should be determined by analyzing concentrations outside the zone of remediation, while for other types of technologies concentration or mass decreases should be measured inside the zone of remediation. Demonstrating How the Technology Works The second type of evidence needed to prove innovative remediation technologies the cause-and-effect evidence comes from data that link the basic risk reduction criteria with the technology being tested.
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From page 206... ...
- Reaction to changes in ground water chemistry - Microstructural analyses of composition Geochemical conditions that affect leachability of stabilized materials (pH, Eh, competing ions, complexing agents, organic liquids, etc.) Increased ratio of immobile- to mobile-phase contaminants Fluid transport properties of solidified material - Permeability - Porosity - Hydraulic gradient across monolith - Rate of water flow through monolith Indicators of liquid/gas flow field consistent with technology (i.e., indication that flow through the stabilized or contained region is blocked)
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From page 207... ...
One approach is to use models to predict the behavior of contaminants under natural conditions and compare it with contaminant behavior during and following application of the remediation technology. A second approach is to use models to evaluate the sensitivity of soil or ground water quality variables to introduction of the remediation technology by simulating how those variables differ under natural and remediation conditions.
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From page 209... ...
TESTING REMEDIATION TECHNOLOGIES 209 types of data, allowing the user to evaluate the trade-offs between information, cost, and uncertainty when using different types of data. A final approach is to use models to determine the optimal experimental design to maximize information content of data while minimizing cost and uncertainty.
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From page 210... ...
Biological and Chemical Reaction Technologies In the process of transforming or immobilizing contaminants, biological and chemical reactions alter the soil and ground water chemistry in ways that can be documented to prove that the reaction processes are taking place. The observed chemical changes should follow directly from the chemical equations that define reactants and products and their ratios.
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From page 211... ...
TESTING REMEDIATION TECHNOLOGIES 211 where CnHm represents a particular petroleum hydrocarbon. This equation can be used to determine how much O2 will be consumed and how much CO2 produced from the degradation of 1 mole (or 1 gram)
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From page 212... ...
Conservative tracers are not affected by biological and chemical reactions associated with the remediation technologies but are affected by all other nonreactive processes. Thus, they can be used to evaluate in situ reactions by documenting a decreased ratio of chemical reactant, or an increased ratio of transformation product, to tracer.
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From page 213... ...
Figure 5-1 shows how a technology would be proven under ideal circumstances: starting with theoretical concepts, proving these concepts in laboratory experiments and then in field tests, and then demonstrating the technology at full scale in the field. Some technologies, such as reactive barriers for in situ ground water remediation (see Box 5-6)
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From page 215... ...
However, the amount and specific types of data needed are highly specific to the individual technology and to the site where it is being tested. The data must minimize uncertainties associated with describing the complex heterogeneities of the subsurface environment, contaminant distribution, processes that control fate and transport of contaminants, and processes that control performance of the remediation technology.
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From page 216... ...
SELECTING A TEST SITE In selecting a test site for an innovative remediation technology, technology developers usually confront one of two situations: either the developer will have a potential client and will need to demonstrate the technology at that client's site, or the developer will not have a client and will need to seek a test site available through various government programs. In the first case, the developer must face the question of how to select a location at the client's contaminated site to field test the technology.
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From page 217... ...
The types of data gathered for each of these components of site characterization will depend in part on the remediation technology being evaluated and in part on the types of contaminants present at the site. The end result of the site characterization will be a conceptual model showing locations of contaminant
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From page 219... ...
This step of site characterization will be the same regardless of the type of technology being tested, because a thorough documentation of contaminant distribution is essential for designing the technology installation and understanding the
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From page 220... ...
This step in site characterization will be the same regardless of the type of remediation technology being tested, because a detailed understanding of ground water and contaminant movement is essential for designing pilot tests of any remediation technology. Included in this stage of site characterization are an
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From page 221... ...
evaluation of site geology; characterization of stratigraphy, including types, thicknesses, and lateral extent of aquifer units and confining units; measurement of depth to ground water, ground water recharge and discharge points, hydraulic gradients, and preferential flow paths; quantification of aquifer physical properties, including hydraulic conductivity, porosity, and grain size distribution, as well as the variations in these properties with location; and quantification of vadose zone properties, including gas and water permeability. The third component of site characterization quantification of aquifer geochemistry involves measuring any chemical properties of the ground water that will affect the fate of the contaminants and performance of the remediation technology.
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From page 222... ...
222 INNOVATIONS IN GROUND WATER AND SOIL CLEANUP and aquifer materials, mineralogy, sorption potential of solid materials, presence or absence of indigenous microbes and their biodegradation potential, nutrient conditions, substances that may inhibit or compete with biodegradation, and any other biogeochemical properties that might play a role in remediation and in the natural fate of contaminants in the absence of remediation. Design of a data collection plan for understanding biogeochemical process dynamics will vary with the type of remediation technology being tested, because different types of technologies will be influenced by different biogeochemical processes.
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From page 223... ...
Once the site is adequately characterized, a test plot should be chosen that represents conditions at the site but is simple enough to minimize uncertainties in evaluating technology performance. Ensuring that the test plot is reasonably representative of the site is essential for the scaleup stage of the technology test.
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From page 224... ...
While the test area must be simple enough to allow evaluation of technology performance, at the same time it must be representative of site conditions. That is, the test volume must contain a geostatistically representative number of the geologic and contaminant features likely to be critical in full-scale project implementation.
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From page 225... ...
Testing at a National Test Site Until the mid-199Os, very few sites were available for researchers to test innovative remediation technologies in the field without first having a client interested in buying the technology. Essentially the only option was to test technologies under the Superfund Innovative Technology Evaluation (SITE)
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From page 227... ...
Table 5-3 lists federal programs that provide assistance to developers needing sites or other forms of support for field testing innovative remediation technologies. Some of these programs, such as the Navy' s Environmental Leadership Program, guarantee full-scale use of any technology successfully demonstrated under the program (EPA, 1996a)
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From page 228... ...
Permeability and degree of saturation are the two hydrogeologic factors that most affect treatability. As discussed in this chapter, there are generally two purposes for testing the performance of innovative remediation technologies.
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From page 230... ...
The rows organize geologic settings on the basis of texture and saturation. The figure shows four groups of contaminated sites: easy to treat (category D, moderately difficult to treat (category II)
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From page 231... ...
High contaminant solubility complicates in situ treatment because it causes more contaminant mass to dissolve in ground water, making contaminant volatilization more difficult. However, the high volatility and reactivity of contaminants in category I make treatment of these contaminants in homogeneous saturated aquifer formations relatively easy.
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From page 232... ...
A technology for treating a site in this category is easily extended to other sites within this same category with contaminants for which the technology is appropriate. Category II represents contaminated sites that are moderately difficult to treat.
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From page 233... ...
Testing is usually directed at identifying conditions that may limit the applicability of the technology to the site. For example, application of a bioremediation process at a site contaminated with phenol would require testing to determine that the site geo
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From page 234... ...
763-6512 Identifies and field tests innovative John Caporal, Air Force environmental technologies, (210) 536-2394 including remediation technologies Selects laboratory-proven technologies with DOD market application and moves them to the field for rigorous testing Dr.
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From page 235... ...
Program Selects innovative remediation technologies for full-scale application at Naval Air Station North Island in San Diego, California, and Naval Station Mayport in Jacksonville, Florida Supports bench- and pilot-scale studies of innovative remediation technologies Ted Zagrobelny, Navy (703) 325-8176 Annette Gatchette, EPA (513)
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From page 236... ...
As shown in Table 5-5, multiple pilot tests may be necessary. A problem in determining either the efficacy or the applicability of technologies for sites in this category is that success at one
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From page 237... ...
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From page 238... ...
< approximately 1 mm Hg Reactivity: High - biodegradable, oxidizable; Low - recalcitrant Solubility: High > approximately 10,000 mg/liter; Low < approximately 1,000 mg/liter stage of testing does not assure success at a subsequent stage, and scaleup of the technology may be difficult. While contaminant and hydrogeologic properties exert the primary influence on the amount of site-specific testing required prior to application of an innovative remediation technology, characteristics of the technology also influence the amount and detail of site-specific data that will need to be collected prior to installation of the technology.
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From page 239... ...
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From page 240... ...
Thus, approaches that bring the contaminants to the technology have an advantage in both the amount and type of data needed for site-to-site transfer and in the amount and type of data needed for evaluating the technology. TECHNOLOGY PERFORMANCE VERIFICATION The wide variation in methods used to assess the performance of innovative remediation technologies has made it very difficult for potential clients to judge the validity of remediation technology performance data.
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From page 241... ...
and the California Environmental Protection Agency Technology Certification Program. Although the programs listed in Box 5-12 offer opportunities to report remediation technology performance data, independently verify these data, and specify steps necessary for regulatory approval of innovative remediation technologies, the existence of such a wide variety of programs in itself creates confusion for remediation technology developers and purchasers.
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From page 244... ...
It should also specify the range of contaminant types and hydrogeologic conditions for which the technology is appropriate, and separate performance data should be provided for each different type of condition. Performance data should be entered in the coordinated remediation technologies data bases recommended in Chapter 3.
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From page 245... ...
Several formal RTDF teams are in place to develop innovative remediation technologies, and the RTDF is considering establishing more such teams (Ketch, 1997~. The first RTDF team formed is known as the Lasagna Consortium_.
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From page 246... ...
While such industry and government partnerships may not solve all the problems associated with testing and commercialization of remediation technologies, they should be encouraged as a potentially effective means for involving major stakeholders in mustering national resources to find solutions. CONCLUSIONS The wide variation in protocols used to assess the performance of innovative technologies for ground water and soil remediation has interfered with comparisons of different technologies and evaluation of performance data.
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From page 247... ...
RECOMMENDATIONS To standardize performance testing protocols and improve the transferability of performance data for innovative remediation technologies, the committee recommends the following: · In proving performance of an innovative remediation technology, technology developers should provide data from field tests to answer the following two questions: 1. Does the technology reduce risks posed by the soil or ground water contamination?
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From page 248... ...
The program should be administered by the EPA and implemented by either EPA laboratories, a private testing organization, a professional association, or a nonprofit research institute. It should receive adequate funding to include the full range of ground water and soil remediation technologies and to test a wide variety of technologies each year.
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From page 249... ...
· Data gathered from technology performance tests under the verif;cation program should be entered in the coordinated national remediation technologies data bases recommended in Chapter 3. Data should be included for technologies that were successfully verified and for those that failed the verification process.
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From page 250... ...
1994. Alternatives for Ground Water Cleanup.
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From page 251... ...
1995. The in situ treatment of trichloroethene-contaminated groundwater using a reactive barrier results of laboratory feasibility studies and preliminary design considerations.
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