Modeling in Situ Bioremediation of Perchlorate-contaminated Groundwater PDF Download

Author: Roland E. Secody
Publisher:
ISBN:
Category : Groundwater
Languages : en
Pages : 226

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Author: Peter G. Chosa
Publisher:
ISBN: 9781423518594
Category : Bioremediation
Languages : en
Pages : 193

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Book Description
Perchlorate contaminated groundwater is rapidly becoming a significant environmental remediation issue for the Department of Defense. In this study, an existing numerical model that simulates the operation of a Horizontal Flow Treatment Well (HFTW) system to effect the in situ biodegradation of perchlorate through the addition of an electron donor is modified to include a submodel that describes bioclogging. Bioclogging restricts flow out of the HFTW due to the accumulation of biomass directly adjacent to the well. The modified model is then applied to an existing perchlorate contaminated site that will be used for an evaluation of the HFTW technology. Simulations were conducted to determine the impact of altering various engineered parameters on HFTW performance. Simulation results indicate that higher time averaged electron donor concentrations and HFTW pumping rates lead to more perchlorate degradation in terms of total mass of perchlorate removed. Simulation results also indicate that varying the electron donor addition schedule has little impact on HFTW performance. The simulations conducted in this study show that, regardless of the engineered parameter values, bioclogging does not impact the ability of the HFTW technology to effect in situ biodegradation of perchlorate at the evaluation site.

Author: Hans F. Stroo
Publisher: Springer Science & Business Media
ISBN: 0387849211
Category : Technology & Engineering
Languages : en
Pages : 281

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In the late 1970s and early 1980s, our nation began to grapple with the legacy of past disposal practices for toxic chemicals. With the passage in 1980 of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as Superfund, it became the law of the land to remediate these sites. The U. S. Department of Defense (DoD), the nation’s largest industrial organization, also recognized that it too had a legacy of contaminated sites. Historic operations at Army, Navy, Air Force, and Marine Corps facilities, ranges, manufacturing sites, shipyards, and depots had resulted in widespread contamination of soil, groundwater, and sediment. While Superfund began in 1980 to focus on remediation of heavily contaminated sites largely abandoned or neglected by the private sector, the DoD had already initiated its Installation Restoration Program in the mid 1970s. In 1984, the DoD began the Defense Environmental Restoration Program (DERP) for contaminated site assessment and remediation. Two years later, the U. S. Congress codified the DERP and directed the Secretary of Defense to carry out a concurrent program of research, development, and demonstration of innovative remediation technologies. As chronicled in the 1994 National Research Council report, “Ranking Hazardous-Waste Sites for Remedial Action”, our early estimates on the cost and suitability of existing technologies for cleaning up contaminated sites were wildly optimistic. Original estimates, in 1980, projected an average Superfund cleanup cost of a mere $3.

Author: Mark R. Knarr
Publisher:
ISBN: 9781423502609
Category : Bioremediation
Languages : en
Pages : 112

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Book Description
Combining horizontal flow treatment wells (HFTWs) with in situ biodegradation is an innovative approach with the potential to remediate perchlorate-contaminated groundwater. A technology model was recently developed that combines the groundwater flow induced by HFTWs with in situ biodegradation processes that result from using the HFTWs to mix electron donor into perchlorate-contaminated groundwater. A field demonstration of this approach is planned to begin this year. In order to apply the technology in the field, project managers need to understand how contaminated site conditions and technology design parameters impact technology performance. One way to gain this understanding is to use the technology model to select engineering design parameters that optimize performance under given site conditions. In particular, a project manager desires to design a system that: 1) maximizes perchlorate destruction; 2) minimizes treatment expense; and 3) attains regulatory limits on down gradient contaminant concentrations. Unfortunately, for a relatively complex technology with a number of engineering design parameters to determine, as well as multiple objectives, system optimization is not straightforward. In this study, a multi-objective genetic algorithm (MOGA) is used to determine design parameter values (flow rate, well spacing, concentration of injected electron donor, and injection schedule) that optimize the first two objectives noted; to maximize perchlorate destruction while minimizing cost. Four optimization runs are performed, using two different remediation time spans (300 and 600 days) for two different sets of site conditions. Results from all four optimization runs indicate that the relationship between perchlorate mass removal and operating cost is positively correlated and nonlinear.

Author: Jeffrey C. Parr
Publisher:
ISBN: 9781423511878
Category : Groundwater
Languages : en
Pages : 155

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Book Description
Groundwater contamination by perchlorate has recently been recognized as a significant environmental problem across the United States, and especially at Department of Defense facilities. In this study, a model is used to evaluate the potential of a innovative in situ bioremediation technology using Horizontal Flow Treatment Wells (HFTWs) to manage perchlorate-contaminated groundwater. The technology uses HFTWs to mix an electron donor into perchlorate-contaminated groundwater in order to promote reduction of the perchlorate by indigenous microorganisms in bioactive zones within the aquifer, as well as recirculate the contaminated water between treatment well pairs to achieve multiple passes of contaminated water through the bioactive zones. The model used in this study couples a three-dimensional fate and transport model, which simulates advective/ dispersive transport of solutes induced by regional groundwater flow and operation of the HFTW's, with a biodegradation model that simulates perchlorate reduction, as well as reduction of competing electron acceptors in the groundwater, by indigenous microorganisms. The model was applied to an example site to demonstrate how in situ perchlorate treatment might be implemented. A sensitivity analysis using the model is also conducted to evaluate which engineered and environmental parameters most affect technology performance. Model simulation results demonstrate that this technology may be effective in managing perchlorate-contaminated groundwater. The recirculation induced by the HFTW system results in increased treatment efficiency, as compared to treatment that would be achieved by a single pass of contaminated water through the bioactive zones. It was observed that the model was very sensitive to several kinetic parameters, indicating that a fruitful area for future research would be to study how these important parameters can be accurately quantified for given geochemical and microbiological conditions.

Author: John Christ
Publisher:
ISBN: 9781423567721
Category :
Languages : en
Pages : 128

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Book Description
The limitations of conventional groundwater remediation technologies have led to the development of innovative technologies which may achieve national hazardous waste site remediation goals. Before an innovative technology can be implemented in the field, remedial project managers, regulators and other stakeholders require adequate modeling tools to help assess the applicability of the technology at a particular site. This modeling study investigates how an innovative technology, in situ cometabolic bioremediation, might be implemented to remediate a TCE-contaminated site, under different site conditions. A steady- state model is developed which couples an analytical expression to simulate the effect of flow between multiple pumping and injection wells, with an expression to calculate TCE removal as groundwater circulates through in situ bioreactors established around the injection wells. Varying site conditions and well configurations are investigated to determine their effect on the overall treatment efficiency of a system. A dual screen well design is found to be an effective method for contaminant capture and treatment given typical values of anisotropy. Investigation of a multiple row implementation concept proves it to be an effective configuration for site cleanup. The model is integrated into interactive software which serves as a technology screening tool.

Author: Liyan Jin
Publisher:
ISBN:
Category : Groundwater
Languages : en
Pages : 148

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 80

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The Applied Technology Department at the Indian Head Division, Naval Surface Warfare Center and Shaw Environmental, Inc., have just successfully completed a field demonstration of in situ bioremediation of a groundwater aquifer contaminated with perchlorate. Using a recirculation cell design, naturally occurring microorganisms were stimulated to degrade perchlorate by injecting a food source (lactate) and neutralizing the groundwater acidity with a carbonate buffer. Starting with perchlorate concentrations in excess of 210 mg/L, perchlorate levels were reduced by more than 95% in eight of the nine test plot monitoring wells over the 5 months of sampling. In two of the monitoring wells, the perchlorate levels were lowered to less than 5 ppb. In addition to the perchlorate levels and the pH, alkalinity, nitrate, and sulfate concentrations were measured. In situ bioremediation techniques are much less expensive and significantly lower in maintenance than traditional ex situ pump-and-treat systems. This is the first field trial conducted on the east coast of the United States, the first trial performed in an acidic aquifer, and the first demonstration of treating in situ perchlorate levels in excess of 200 mg/L. This project provides new and valuable information concerning the application of bioremediation for in situ perchlorate treatment.

Author: Randall J. Cramer
Publisher:
ISBN: 9781423514664
Category :
Languages : en
Pages : 80

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Book Description
The Applied Technology Department at the Indian Head Division, Naval Surface Warfare Center and Shaw Environmental, Inc., have just successfully completed a field demonstration of in situ bioremediation of a groundwater aquifer contaminated with perchlorate. Using a recirculation cell design, naturally occurring microorganisms were stimulated to degrade perchlorate by injecting a food source (lactate) and neutralizing the groundwater acidity with a carbonate buffer. Starting with perchlorate concentrations in excess of 210 mg/L, perchlorate levels were reduced by more than 95% in eight of the nine test plot monitoring wells over the 5 months of sampling. In two of the monitoring wells, the perchlorate levels were lowered to less than 5 ppb. In addition to the perchlorate levels and the pH, alkalinity, nitrate, and sulfate concentrations were measured. In situ bioremediation techniques are much less expensive and significantly lower in maintenance than traditional ex situ pump- and-treat systems. This is the first field trial conducted on the east coast of the United States, the first trial performed in an acidic aquifer, and the first demonstration of treating in situ perchlorate levels in excess of 200 mg/L. This project provides new and valuable information concerning the application of bioremediation for in situ perchlorate treatment.

Author: Bruce E. Rittmann
Publisher: Taylor & Francis
ISBN: 9780815513483
Category : Science
Languages : en
Pages : 298

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Book Description
This critical review of the status of in situ bioremediation, which is used to clean up contaminated groundwater aquifers and surface soils, has been organized according to possibilities and restrictions. Possibilities are based on present knowledge and indicate that in situ bioremediation can achieve decontamination of aquifers and soils. Restrictions encompass the scientific, engineering, legal, and other questions that stand in the way of successful development and application of in situ bioremediation. Although much has been written about bioremediation, this critical review is unique because it is comprehensive, critical, and integrated. This situation was no accident; the organization of the authorship team and the report's contents were designed to achieve each of the three attributes. Combining a good plan, outstanding individuals contributing, and an incredible amount of work, they created a critical review that defines the technical and non-technical issues that will determine how much of an impact in situ bioremediation makes on solving the world's challenges for cleanup of our legacy of improperly disposed of materials. Readers of this review will find the issues identified and connected. They will have a solid foundation for research, application, or evaluation of in situ bioremediation in the future.