Field-Scale Evaluation of Monitored Natural Attenuation for Dissolved Chlorinated Solvent Plumes PDF Download
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 455
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Book Description
The methodology, case-study examples, and recommendations described in this report are intended to provide restoration program managers, their support staff, and the regulatory community with descriptions of methods and tools that can be used to advance the state-of-practice for monitoring and documenting the long-term sustainability of monitored natural attenuation (MNA)-based remedies for chlorinated solvent-impacted groundwater. Specifically, this report 1) presents a strategy and framework for quantitatively assessing the sustainability of MNA-based remedies for groundwater at chlorinated solvent-impacted sites, 2) provides case-study reviews using existing long-term monitoring (LTM) data sets from multiple United States Air Force sites where chlorinated solvents exceed closure criteria, and 3) summarizes observations and recommendations that were developed when working through the case-study examples.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 455
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Book Description
The methodology, case-study examples, and recommendations described in this report are intended to provide restoration program managers, their support staff, and the regulatory community with descriptions of methods and tools that can be used to advance the state-of-practice for monitoring and documenting the long-term sustainability of monitored natural attenuation (MNA)-based remedies for chlorinated solvent-impacted groundwater. Specifically, this report 1) presents a strategy and framework for quantitatively assessing the sustainability of MNA-based remedies for groundwater at chlorinated solvent-impacted sites, 2) provides case-study reviews using existing long-term monitoring (LTM) data sets from multiple United States Air Force sites where chlorinated solvents exceed closure criteria, and 3) summarizes observations and recommendations that were developed when working through the case-study examples.
Author: Commission on Geosciences, Environment, and Resources
Publisher: National Academies Press
ISBN: 0309069327
Category : Science
Languages : en
Pages : 289
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Book Description
In the past decade, officials responsible for clean-up of contaminated groundwater have increasingly turned to natural attenuation-essentially allowing naturally occurring processes to reduce the toxic potential of contaminants-versus engineered solutions. This saves both money and headaches. To the people in surrounding communities, though, it can appear that clean-up officials are simply walking away from contaminated sites. When is natural attenuation the appropriate approach to a clean-up? This book presents the consensus of a diverse committee, informed by the views of researchers, regulators, and community activists. The committee reviews the likely effectiveness of natural attenuation with different classes of contaminants-and describes how to evaluate the "footprints" of natural attenuation at a site to determine whether natural processes will provide adequate clean-up. Included are recommendations for regulatory change. The committee emphasizes the importance of the public's belief and attitudes toward remediation and provides guidance on involving community stakeholders throughout the clean-up process. The book explores how contamination occurs, explaining concepts and terms, and includes case studies from the Hanford nuclear site, military bases, as well as other sites. It provides historical background and important data on clean-up processes and goes on to offer critical reviews of 14 published protocols for evaluating natural attenuation.
Author:
Publisher:
ISBN:
Category : Arsenic
Languages : en
Pages : 124
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Book Description
V.3 ... consists of individual chapters that describe 1) the conceptual background for radionuclides, including tritium, radon, strontium, technetium, uranium, iodine, radium, thorium, cesium, plutonium-americium and 2) data requirements to be met during site characterization.
Author: Todd H. Wiedemeier
Publisher: John Wiley & Sons
ISBN: 9780471197492
Category : Technology & Engineering
Languages : en
Pages : 634
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Book Description
The first comprehensive guide to one of today's most innovative approaches to environmental contamination Natural attenuation is gaining increasing attention as a nonintrusive, cost-effective alternative to standard remediation techniques for environmental contamination. This landmark work presents the first in-depth examination of the theory, mechanisms, and application of natural attenuation. Written by four internationally recognized leaders in this approach, the book describes both biotic and abiotic natural attenuation processes, focusing on two of the environmental contaminants most frequently encountered in groundwater--fuels and chlorinated solvents. The authors draw on a wealth of combined experience to detail successful techniques for simulating natural attenuation processes and predicting their effectiveness in the field. They also show how natural attenuation works in the real world, using numerous examples and case studies from a wide range of leading-edge projects nationwide involving fuel hydrocarbons and chlorinated solvents. Finally, they discuss the evaluation and assessment of natural attenuation and explore the design of long-term monitoring programs. An indispensable reference for anyone working in environmental remediation, Natural Attenuation of Fuels and Chlorinated Solvents in the Subsurface is essential reading for scientists and engineers in a range of industries, as well as state and federal environmental regulators, and professors and graduate students in environmental or chemical engineering.
Author: B. Looney
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Monitored natural attenuation (MNA) and enhanced attenuation (EA) are two environmental management strategies that rely on a variety of attenuation processes to degrade or immobilize contaminants and are implemented at appropriate sites by demonstrating that contaminant plumes have low risk and are stable or shrinking. The concept of a mass balance between the loading and attenuation of contaminants in a groundwater system is a powerful framework for conceptualizing and documenting the relative stability of a contaminant plume. As a result, this concept has significant potential to support appropriate implementation of monitored natural attenuation (MNA) and enhanced attenuation (EA). For mass balance to be useful in engineering practice, however, it is necessary to quantify it in practical ways that facilitate overall site remediation and which are consistent with existing regulatory guidance. Two divergent philosophies exist for quantifying plume stability--empirical and deterministic. The first relies on historical contaminant concentration data and bulk geochemical information from a monitoring well network and documents plume stability using trend analysis and statistical tools. This empirical approach, when feasible, provides powerful and compelling documentation of plume behavior and mass balance. It provides an interpretation on a relevant scale under field conditions. It integrates the operative attenuation processes measured by observing their actual impact on the plume. The power of the empirical approach was recognized early in the development of MNA guidance and protocols and it is currently the basis of the three lines of evidence used in MNA studies. The empirical approach has some weaknesses, however. It requires a relatively long period of undisturbed historical data. Thus it cannot be effectively applied to sites where active remediation was initiated quickly and is currently operating. It cannot be used as a tool to determine how much source removal is needed or when to turn off active remediation and transition to MNA. It cannot be used to evaluate potential enhancement options (unless a long period of post enhancement monitoring is planned). It provides only indirect information about process and treats the plume as a ''black box''. The empirical approach has the advantage that, when sufficient monitoring data are available, the attenuation capacity can be defined inexpensively and with a high degree of certainty. Alternatively, a deterministic approach can be used to assess mass balance and plume stability. In this approach, the physical, chemical, and biological attenuation processes are used to assess contaminant loading and attenuation. The deterministic approach has the advantage that, when sufficient hydrologic, geochemical, and microbiological data are available, it is possible to project how a system will respond to contaminant removal actions or enhancements of natural attenuation processes. The ''black box'' of the plume is taken apart, quantified, and put back together again. The disadvantage of the deterministic approach is that it is difficult to measure all or most of the relevant hydrologic, geochemical, and biological parameters with any certainty. Case studies over the past decade demonstrate that empirical and deterministic approaches to MNA/EA are not mutually exclusive. These studies document that improved decision support and efficiency result by combining these methods based on the individual challenges presented by a given site. Whenever possible, the empirical approach is used to quantify mass loading and attenuation capacity (mass of contaminant/unit time) at particular sites. This is the most effective way to demonstrate the efficiency of ongoing natural attenuation processes in accordance with current regulatory guidance. But in addition, the monitoring well networks needed to apply the empirical approach can also yield estimates of the hydrologic, geochemical, and biological parameters needed to apply deterministic models. These models can then be used to estimate how contaminant behavior will change over time, as contaminant mass is removed, or if attenuation mechanisms are enhanced by engineering methods. The dual use of these empirical and deterministic approaches can help integrate the use of MNA and EA for overall site remediation.
Author: National Research Council
Publisher: National Academies Press
ISBN: 030909447X
Category : Science
Languages : en
Pages : 371
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Book Description
At hundreds of thousands of commercial, industrial, and military sites across the country, subsurface materials including groundwater are contaminated with chemical waste. The last decade has seen growing interest in using aggressive source remediation technologies to remove contaminants from the subsurface, but there is limited understanding of (1) the effectiveness of these technologies and (2) the overall effect of mass removal on groundwater quality. This report reviews the suite of technologies available for source remediation and their ability to reach a variety of cleanup goals, from meeting regulatory standards for groundwater to reducing costs. The report proposes elements of a protocol for accomplishing source remediation that should enable project managers to decide whether and how to pursue source remediation at their sites.
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309065496
Category : Science
Languages : en
Pages : 301
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Book Description
This book presents a comprehensive, up-to-date review of technologies for cleaning up contaminants in groundwater and soil. It provides a special focus on three classes of contaminants that have proven very difficult to treat once released to the subsurface: metals, radionuclides, and dense nonaqueous-phase liquids such as chlorinated solvents. Groundwater and Soil Cleanup was commissioned by the Department of Energy (DOE) as part of its program to clean up contamination in the nuclear weapons production complex. In addition to a review of remediation technologies, the book describes new trends in regulation of contaminated sites and assesses DOE's program for developing new subsurface cleanup technologies.
Author: Robert E. Hinchee
Publisher:
ISBN:
Category : Nature
Languages : en
Pages : 290
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Book Description
An international group of researchers and engineers discuss using natural attenuation to degrade contaminants and thereby remediate soils and groundwater. This volume describes laboratory studies and field demonstrations in support of subsurface remediation at military, manufactured gas plant, landfill, petroleum spill, and other sites. The contaminants of concern include benzene, toluene, ethyl-benzene, and xylenes (BTEX); naphthalene; trichloroethene; trichlorethane; and perchloroethylene. Analytical methods for assessing the potential for natural attenuation (passive bioremediation) at a given site and for confirming and documenting efficacy are discussed.
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309278139
Category : Nature
Languages : en
Pages : 423
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Book Description
Across the United States, thousands of hazardous waste sites are contaminated with chemicals that prevent the underlying groundwater from meeting drinking water standards. These include Superfund sites and other facilities that handle and dispose of hazardous waste, active and inactive dry cleaners, and leaking underground storage tanks; many are at federal facilities such as military installations. While many sites have been closed over the past 30 years through cleanup programs run by the U.S. Department of Defense, the U.S. EPA, and other state and federal agencies, the remaining caseload is much more difficult to address because the nature of the contamination and subsurface conditions make it difficult to achieve drinking water standards in the affected groundwater. Alternatives for Managing the Nation's Complex Contaminated Groundwater Sites estimates that at least 126,000 sites across the U.S. still have contaminated groundwater, and their closure is expected to cost at least $110 billion to $127 billion. About 10 percent of these sites are considered "complex," meaning restoration is unlikely to be achieved in the next 50 to 100 years due to technological limitations. At sites where contaminant concentrations have plateaued at levels above cleanup goals despite active efforts, the report recommends evaluating whether the sites should transition to long-term management, where risks would be monitored and harmful exposures prevented, but at reduced costs.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 222
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Book Description
A substantial number of chlorinated solvent ground-water plumes at hazardous waste sites may potentially discharge into ecologically sensitive wetland environments. Although chlorinated solvents tend to be relatively resistant to degradation within most aquifer systems, rapid and complete transformations can occur within the organic-rich reducing environment typical of wetland sediments, suggesting that monitored natural attenuation may be an effective remediation option for discharges into wetlands. A previous study by the U.S. Geological Survey (USGS) in a freshwater tidal wetland at Aberdeen Proving Ground (APG), Maryland, showed complete attenuation of chlorinated solvents before the wetland surface or creek was reached. A collaborative study by the USGS and the Air Force Research Laboratory under the Department of Defense Environmental Security Technology Certification Program (ESTCP) was conducted to determine if the natural attenuation of chlorinated solvents that occurs at the APG wetland site can occur at wetland sites located in different hydrogeologic environments and to assist in the transfer of this technology to other potential users. The objectives of this ESTCP demonstration project were to (1) assess and compare the extent of natural attenuation of chlorinated solvent at three wetland sites in different hydrogeologic environments; (2) to demonstrate and compare different methods of sampling and analysis for collecting the site data needed to evaluate natural attenuation in wetlands; and (3) to develop a technical protocol for the assessment of natural attenuation of chlorinated solvent plumes discharging into wetlands.
