Modeling the Effect of Nonlinear and Rate-Limited Sorption on the Natural Attenuation of Chlorinated Ethenes PDF Download
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Author: Peter P. Feng
Publisher:
ISBN: 9781423538936
Category : Chlorohydrocarbons
Languages : en
Pages : 81
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Book Description
Chlorinated solvents like tetrachloroethene (PCE) and trichloroethene (TCE) are the most common detected groundwater contaminants at Department of Defense installations in the United States. Unfortunately, technologies conventionally used to remediate chlorinated solvent-contaminated groundwater often fall short of achieving regulatory goals. Natural attenuation of chlorinated solvents offers an alternative remediation strategy that may achieve goals. However, the processes involved with natural attenuation are not fully understood, and this lack of understanding has hindered acceptance of natural attenuation by regulatory agencies. This study involved use of a numerical model that incorporated the physical, chemical, and biological processes thought to be relevant to the fate and transport of chlorinated ethenes in the subsurface. The model was used to conduct a parameter sensitivity analysis, to investigate the effect of non-linear and rate-limited sorption processes on the natural attenuation of chlorinated ethenes. The model showed that both rate-limited and non-linear sorption resulted in early arrival of contaminant at wells downgradient of a source area, as well as persistence of contamination at the wells for long periods of time.
Author: Peter P. Feng
Publisher:
ISBN: 9781423538936
Category : Chlorohydrocarbons
Languages : en
Pages : 81
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Book Description
Chlorinated solvents like tetrachloroethene (PCE) and trichloroethene (TCE) are the most common detected groundwater contaminants at Department of Defense installations in the United States. Unfortunately, technologies conventionally used to remediate chlorinated solvent-contaminated groundwater often fall short of achieving regulatory goals. Natural attenuation of chlorinated solvents offers an alternative remediation strategy that may achieve goals. However, the processes involved with natural attenuation are not fully understood, and this lack of understanding has hindered acceptance of natural attenuation by regulatory agencies. This study involved use of a numerical model that incorporated the physical, chemical, and biological processes thought to be relevant to the fate and transport of chlorinated ethenes in the subsurface. The model was used to conduct a parameter sensitivity analysis, to investigate the effect of non-linear and rate-limited sorption processes on the natural attenuation of chlorinated ethenes. The model showed that both rate-limited and non-linear sorption resulted in early arrival of contaminant at wells downgradient of a source area, as well as persistence of contamination at the wells for long periods of time.
Author: Tarek A. Kassim
Publisher: Springer Science & Business Media
ISBN: 9783540235859
Category : Technology & Engineering
Languages : en
Pages : 268
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Book Description
Volume 3: Engineering Modeling and Sustainability. This 3-volume reference presents the latest findings in impact assessment of recycled hazardous waste materials on surface and ground waters. Topics covered include chemodynamics, toxicology, modeling and information systems. The book serves as a practical guide for the monitoring, design, management, or conduct of environmental impact assessment. Each volume contains the table of contents of all volumes.
Author: Andrea Leeson
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 328
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Book Description
The symposium included 600 presentations in 50 sessions on bioremediation and supporting technologies used for a wide range of contaminants already in, or poised to invade, soil, groundwater, and sediment. Three hundred and fifty-two papers were selected and organized into ten volumes. Volume two's articles address the use of natural attenuation to remediate sites with a variety of hydrocarbons and chlorinated compounds contaminating porous media and groundwater. Methods of encouraging naturally occurring microbial activity are discussed, along with sampling, assessment, and long-term monitoring techniques and devices. Articles average eight pages and contain abstracts and references. Annotation copyrighted by Book News Inc., Portland, OR.
Author: Zackary William Munger
Publisher:
ISBN:
Category :
Languages : en
Pages : 102
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Book Description
In the subsurface, chlorinated solvent sorption to aquifer materials hinders remediation efforts and makes predicting the transport and fate of chlorinated solvents in groundwater a nontrivial enterprise. Due to heterogeneity in natural sorbents, there is a lack of clear evidence for a sorption model that can reliably simulate sorption behavior across broad aqueous sorbate concentrations on the basis of quantifiable sorbent characteristics. The goal of this study was to test if there is a sorption model that can be shown to be the best choice for simulating trichloroethene (TCE) sorption to natural sorbents and to link the sorption behavior to sorbent characteristics. Sorption isotherms were collected for four natural sorbents from Ontario and New York. The isotherms span an aqueous concentration range nearly five orders of magnitude. The sorbents contain type II kerogen, a common organic constituent in autochthonous marine sedimentary rocks and more recent allochthonous deposits, making them valid model sorbents. These sorption data were fit with 11 isotherm models common in the literature and founded on various partitioning, adsorption, pore-filling, and dual-mode mechanisms including Freundlich, Langmuir, Tóth, and Polanyi-type models. For all examined sorbents the Polanyi or Polanyi-partition models were ranked as the best fit based on the corrected Akaike Information Criterion, suggesting that pore-filling or combined pore-filling and linear partitioning mechanisms are valid for sorbents that contain kerogen. The estimated linear partitioning coefficients for the Polanyi-partition model were within a factor of four of that predicted on the basis of the fraction of organic carbon and an octanol-water partitioning linear free energy relationship. The sorption capacity term was constant within a factor of three when normalized by the fraction of organic carbon. The A and B fitting parameters remained fairly consistent among the studied sorbents. This study demonstrates that the single and dual-mode Polanyi-partition models are the most plausible to describe TCE sorption to sorbents with kerogen and are more accurate across broad aqueous concentrations than commonly used linear and Freundlich models. Model parameters are shown to be related to sorbent characteristics demonstrating the potential for estimating reliable model parameters from measurable sorbent properties.
Author: DEREK. VEERKAMP
Publisher:
ISBN: 9781423545804
Category :
Languages : en
Pages : 119
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Book Description
Chlorinated solvents and their daughter products are the most common contaminants of groundwater at industrial and military facilities in the United States. Limitations of conventional technologies have intensified efforts to find alternative methods to remediate contaminated sites to regulatory goals set by CERCLA. Natural attenuation of chlorinated solvents is a promising alternative to traditional pump and treat methods but has not been well understood or widely accepted. This modeling study investigated the ability of TCE to completely degrade under various aquifer conditions and rate order constants. It also examined a case study of a former landfill site at Moody AFB. We found unusually high flow of ground water by advection or dispersion inhibits the complete degradation of TCE. High concentrations of sulfate or nitrate inhibit the creation of methanogenic conditions and therefore inhibit reductive dechlorination of TCE. We also found an electron donor co-contaminant a critical factor for the complete destruction of TCE because it creates anaerobic conditions. The model illustrated a possible explanation for the lack of down gradient contaminants at the landfill site may be the coupling of reductive dechlorination and cometabolism naturally attenuation the contaminants.
Author: Manuel Alejandro Salaices Avila
Publisher: Cuvillier Verlag
ISBN: 3865376061
Category :
Languages : en
Pages : 265
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Book Description
Author: Glenn F. Huff
Publisher:
ISBN:
Category : Chlorohydrocarbons
Languages : en
Pages : 36
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Book Description
Author: Harold C. Young
Publisher:
ISBN: 9781423529927
Category : Aquifers
Languages : en
Pages : 95
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Book Description
Chlorinated ethenes are among the most prevalent groundwater contaminants at hazardous waste sites nationwide. In an attempt to manage the risks posed by these contaminants, while controlling costs, monitored natural attenuation (MNA) is being considered as a remediation strategy at many sites. MNA relies on naturally occurring physical, chemical, and biological processes in the subsurface to reduce the risk posed by the contamination. The implementation of MNA, however, requires a detailed understanding of these processes, and how they impact contamination at a particular site. One way to gain this understanding is through contaminant fate and transport modeling. In this study, a deterministic model that includes relevant fate and transport processes was applied to a chlorinated ethene-contaminated field site, at which spatial and temporal data had been collected. Parameters used for model input were obtained from the literature, experimental data, and by calibrating the model using concentration data from 1993. The model was then run in a predictive mode, and simulation results were compared to field data from 1999. Model performance was measured by comparison of observed and simulated concentration contour plots and evaluation of goodness-of-fit statistics. Over the six years the model was run in a predictive mode, the model was found to predict contaminant concentrations reasonably well for the three contaminants that were monitored.
Author: Godage B. Wickramanayake
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 400
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Book Description
- Transformation Processes in Natural Attenuation- Field Characterization/Monitoring for Natural Attenuation- Modeling Natural Attenuation- Natural Attenuation Case Studies- Natural Attenuation of MTBE.
Author: Godage B. Wickramanayake
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 272
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Book Description
- Natural Attenuation Considerations- Natural Attenuation Case Studies I: Chloroethenes- Natural Attenuation Case Studies II: Other Organics and Metals.
