Download or read book Permanganate Flushing of DNAPL Source Zones Experimental and Numerical Investigation written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Permanganate Flushing of DNAPL Source Zones Experimental and Numerical Investigation written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Numerical Investigation of Metabolic Reductive Dechlorination in DNAPL Source Zones written by John Anthony Christ and published by . This book was released on 2005 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt: Among the most intractable environmental remediation problems are those involving the release of dense non-aqueous phase liquids (DNAPLs), such as chlorinated solvents, to the subsurface. Research efforts have focused on the use of numerical models to investigate reductions in contaminant concentrations due to partial mass removal and improvements in the performance of complementary source zone remediation technologies. Previous numerical investigations, however, have been limited to two-dimensional systems. Furthermore, a lack of models capable of simulating the most promising complementary technology, metabolic reductive dechlorination, has limited its application. This work developed and applied compositional multiphase numerical simulators to examine the influence of dimensionality (two-dimensions versus three-dimensions) on DNAPL source zone simulations and to investigate the benefits of stimulating metabolic reductive dechlorination at a chlorinated ethene-DNAPL contaminated site. Results from the dimensionality investigation showed that the simulation of DNAPL migration, entrapment, and dissolution in two dimensions provided reasonable approximations to the behavior simulated in three dimensions. Commonly employed saturation distribution and mass recovery metrics were approximately equivalent. Flux- averaged concentrations simulated in two dimensions, however, tended to be three to four times higher than those simulated in three dimensions. This difference was attributed to dilution at the down gradient boundary. An alternative metric, mass flux reduction, however, yielded better agreement.
Download or read book Permanganate Treatment of DNAPLs in Reactive Barriers and Source Zone Flooding Schemes written by Franklin W. Schwartz and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research involves a combined experimental modeling study that builds on our previous DOE-sponsored work in understanding how KMnO4 can be used with in situ cleanups of contaminated sites. The specific objectives of this study are (1) to describe how solid forms of KMnO4 behave in saturated media, (2) to undertake flow tank studies that examine the hydraulic impact of reaction products (especially MnO2) on the flux of water through the zone of contamination, and (3) to represent process understanding in flow and transport models. We have made excellent progress in addressing these issues through a variety of different laboratory and theoretical investigations, as well as work that summarizes the state of the science. In the space available for this report, we can only summarize the key findings of the study. Readers interested in additional details can refer to the papers that are listed at end of this report. There has been significant industrial interest in the use of KMnO4 schemes for the in situ destruction of various chlorinated solvents. Given our previous work that emphasized some of the problems associated with field applications of the method, we were invited to contribute to a special edition of Environmental & Engineering Geoscience that examined the effects of heterogeneity on in situ remediation schemes. Our review targeted the most common implementation namely the use of an injection/withdrawal system to circulate oxidants (e.g., potassium permanganate, hydrogen peroxide, and Fenton's Reagent) through a source zone containing a dense nonaqueous phase liquid (DNAPL). The review demonstrated with various examples (1) how the efficiency of chemical oxidation is highly dependent on physical and chemical heterogeneities, and (2) how effective delivery is essential for successful remediation. A summary of this work is provided here in Section 1 of the Chapter Methods and Results. We investigated the mineralogy of Mn oxides, and the possibilities of controlling the colloid growth and removing the solid precipitates by dissolution. We determined the chemical formula of the Mn oxide and identified as semi-amorphous potassium-rich birnessite. We also measured the surface properties of the Mn oxide like the specific surface area and point of zero charge (pzc) of the Mn oxide. These findings provide foundation for further investigation of the behavior of Mn oxide precipitates in the remediation environment. We utilized batch experiments to explore the feasibility of applying phosphate to slow down the formation of colloidal Mn oxide. Our results show that phosphate can slow down the formation of the colloids, especially early in the reaction. A model was proposed to describe the reaction process. Our study provides scientific background on the possibility to slow down the formation of colloid during the oxidation scheme by chemical additives. The dissolution kinetics of Mn oxide was evaluated in batch experiments using solutions of citric acid, oxalic acid, and EDTA. Organic acids dissolve Mn oxide quickly. Reaction rates increase with acid concentration, as tested with citric acid. The Mn oxide dissolution mechanism likely involves proton and ligand-promoted dissolution and reductive dissolution. We proposed two models describing the dissolution of Mn oxide by organic acids. The flow tank experiment confirmed the possibilities of restoring permeability damaged by Mn oxide precipitation. There seem to be good possibilities for using citrate and oxalate to control plugging created by the precipitation of Mn oxide. A more details summary of the work on the Mn oxide precipitates is provided here in Section 2 of the Chapter Methods and Results. Another important thrust of our research effort involved a detailed evaluation of the efficiency of TCE removal with time, and the space/time dynamics of the solid-phase oxidation reaction front (Section 3 of the Chapter Methods and Results). The approach involved a very large 3-D flow tank experiment. The progress of TCE destruction and the distribution of MnO2 precipitates were monitored using novel optical and chemical monitoring techniques. The results showed that the efficiency of the KMnO4 treatment of chlorinated solvents in the flushing scheme diminished with time due to the formation of low-permeability reaction zones in the TCE source and along the downstream edge of the TCE plume.
Download or read book In Situ Chemical Oxidation for Groundwater Remediation written by Robert L. Siegrist and published by Springer Science & Business Media. This book was released on 2011-02-25 with total page 715 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides comprehensive up-to-date descriptions of the principles and practices of in situ chemical oxidation (ISCO) for groundwater remediation based on a decade of intensive research, development, and demonstrations, and lessons learned from commercial field applications.
Download or read book Permanganate Treatment of DNAPLs in Reactive Barriers and Source Zone Flooding Schemes written by and published by . This book was released on 2001 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We are conducting basic research on a new delivery scheme that involves mixing the appropriate quantity of KMnO4 as a solid into the zone of DNAPL contamination. This scheme takes advantage of the tendency for reaction products to reduce the permeability of the treatment zone, which will control the dissolution of the solid and keep the MnO4− in contact with the DNAPL. What needs to be determined, however, is how various solid forms of KMnO4 behave in porous media and dissolve under the combined influence of fluid flow and MnO2 precipitation. The goals of this study are to (1) to elucidate the dissolution/reaction processes accompanying the amendment of media containing chlorinated solvents with KMnO4 and (2) to assess the potential for solid KMnO4 amendments as a scheme to clean up source zones. This research involves a combined experimental/modeling study that builds on our previous DOE-sponsored work in understanding of how KMnO4 can be used with in situ cleanups of contaminated sites. The specific objectives of this study are (1) to describe through column experiments how solid forms of potassium permanganate (KMnO4) behave in saturated media with and without TCE and PCE. (2) to undertake flow tank studies that examine the hydraulic impact of reaction products (especially MnO2) on the flux of water through the zone of contamination, and (3) to represent the process understanding in flow and transport models that demonstrate the potential applicability of the approach.
Download or read book Laboratory Investigation of Dense Non aqueous Phase Liquid DNAPL Partial Source Zone Remediation Using Cosolvents written by Andrew Joseph Kaye and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: There are hundreds of thousands of commercial, military, and industrial sites across the country where chemical wastes cause contamination to groundwater. Some of the more challenging sites to clean up contain contaminants as dense non-aqueous phase liquids (DNAPLs). There is currently no consensus in the academic, technical and regulatory communities on the ecological or environmental impacts of DNAPL source zone treatment. While many in-situ technologies have shown the ability to remove a significant portion of the contaminant mass, none are able to remove all of it from the source zone. This study investigates the benefits of partial source zone removal using cosolvent flushing. The benefits were assessed by characterizing the relationship between reductions in DNAPL mass and the corresponding reduction in contaminant mass discharge in several laboratory scale experiments. Also, the effects of fluid override and underride associated with cosolvent flushing on the mass reduction (MR) vs. flux reduction (FR) relationship were investigated. The results indicate a model with beta> 1 may be a good approximation of the MR vs. FR relationship using enhanced dissolution by the cosolvents in systems with similar degrees DNAPL and media heterogeneity. Also, the override and underride associated with cosolvents did not significantly affect their remediation.
Download or read book Permanganate Treatment of DnAPLs in Reactive Barriers and Source Zone Flooding Schemes 1998 Annual Progress Report written by and published by . This book was released on 1998 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goals of this study are: (1) to elucidate the basic mechanisms by which potassium permanganate oxidizes common chlorinated solvents, various constituents in aqueous solution, and porous-medium solids, and (2) to assess the potential for chemical oxidation by potassium permanganate to serve as a remedial scheme involving either source zone flooding or reactive barriers. The combined theoretical and experimental study is designed to contribute fundamental knowledge about reaction pathways, reaction rates, specific intermediates formed, and controls on reaction processes. The specific objectives of this study are: (1) to describe through batch experiments the kinetics and mechanisms by which potassium permanganate oxidizes dissolved tetrachloroethene (PCE), trichloroethene (TCE), and dichloroethene (DCE), (2) to examine using column studies the nature and kinetics of reactions between potassium permanganate, residual DNAPLs (PCE, TCE, and DCE) and porous medium solids, (3) to represent the process understanding in flow and transport models that demonstrate the potential applicability of the approach, and (4) to apply the resulting computer code in the development of appropriate field tests for assessing the approach. Approaching the end of Year 2 of this 3-Year project, the authors can report significant progress in meeting the objectives of the study. Through a series of batch experiments, it has been shown that permanganate oxidation is effective in degrading various chlorinated ethylenes in aqueous solution. The disappearance of chlorinated ethylenes can be simply characterized by a pseudo-first-order model. Degradation half-lives for TCE, cis-1,2-DCE, trans-1,2-DCE and 1,1-DCE reacting with 1mM MnO4− range from about 24 s to 18 min. Degradation of PCE is much slower with a half-life of about 257 min. Overall, the degradation rate is inversely proportional to the number of chlorines present as substituents on ethylenes. These rates of degradation are impressive given the fact that the experiments were run with MnO4− concentrations only a factor of 10 or so greater than that of the particular chlorinated ethylene. It would be feasible in practice to increase rates of reaction by increasing MnO4− concentrations. The experiments also showed how the efficiency of degradation is reduced due to competition from other organic compounds. Contaminated ground water was synthesized as a mixture of ground water and landfill leachate. Three experiments were run with a fixed TCE concentration of 2 mg/L, a concentration of other organic compounds of 101 mg/L (TOC) and concentrations of MnO4− of 20, 80 and 120 mg/L. As expected, the competition for MnO4− led to a reduction in the reaction rate, as compared to experiments with TCE in Milli-Q water. However, with the largest MnO4− concentration, the competition appeared to be offset by other processes that effectively increased the degradation rate of TCE. The preliminary assessment is that colloidal MnO2 was catalyzing reactions between MnO4− and TCE. The authors will explore this aspect of the study in the coming year. Early in the study, the authors confirmed previous work that indicated TCE degraded completely to CO2 in a series of three steps. However, little was known about the overall reaction pathways and intermediates that formed. Preliminary indications were that TCE reacted with MnO4− to produce a cyclic complex, then carboxylic acids, and finally CO2, along with Cl− and MnO2 . Of particular interest in the work were steps two and three. The authors undertook kinetic experiments with radiolabeled TCE (i.e., 1,2-14 C) to understand these reactions.
Download or read book Chlorinated Solvent Source Zone Remediation written by Bernard H. Kueper and published by Springer Science & Business. This book was released on 2014-04-22 with total page 759 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this book is to help engineers and scientists better understand dense nonaqueous phase liquid (DNAPL) contamination of groundwater and the methods and technology used for characterization and remediation. Remediation of DNAPL source zones is very difficult and controversial and must be based on state-of-the-art knowledge of the behavior (transport and fate) of nonaqueous phase liquids in the subsurface and site specific geology, chemistry and hydrology. This volume is focused on the characterization and remediation of nonaqueous phase chlorinated solvents and it is hoped that mid-level engineers and scientists will find this book helpful in understanding the current state-of-practice of DNAPL source zone management and remediation.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Permanganate Treatment of DNAPLs in Reactive Barriers and Source Zone Flooding Schemes 1997 Annual Progress Report written by and published by . This book was released on 1997 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goals of this study are (1) to elucidate the basic mechanisms by which potassium permanganate oxidizes common chlorinated solvents, various constituents in aqueous solution, and porous-medium solids, and (2) to assess the potential for chemical oxidation by potassium permanganate to serve as a remedial scheme involving either source zone flooding or reactive barriers. The research plan involves a combined experimental/modeling study that builds on the extensive previous work in the area of reactive barrier systems, and modeling of reactive contaminant transport. The experimental studies are being undertaken at The Ohio State University by Dr. Schwartz and his co-workers. The modeling work is being conducted in Albuquerque, NM by Dr. Zhang of Intera, Inc. The workplan for this study is designed around the following four objectives (1) to describe through batch experiments the kinetics and mechanisms by which potassium permanganate oxidizes dissolved tetrachloroethene (PCE), trichloroethene (TCE), and dichloroethene (DCE), (2) to examine using column studies the nature and kinetics of reactions between potassium permanganate, residual DNAPLs (PCE, TCE, and DCE) and porous medium solids, (3) to represent the process understanding in flow and transport models that demonstrate the potential applicability of the approach, and (4) to apply the resulting computer code in the development of appropriate field tests for assessing the approach.
Download or read book DNAPL Source Zone Depletion During in Situ Chemical Oxidation ISCO written by Jeffrey L. Heiderscheidt and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Contaminants in the Subsurface written by National Research Council and published by National Academies Press. This book was released on 2005-04-23 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Groundwater and Soil Cleanup written by National Research Council and published by National Academies Press. This book was released on 1999-11-21 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Permanganate Treatment of DNAPLs in Reactive Barriers and Source Zone Flooding Schemes Final Report written by and published by . This book was released on 2000 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study provides a detailed process-level understanding of the oxidative destruction of the organic contaminant emphasizing on reaction pathways and kinetics. A remarkable rise in the MnO− consumption rate with TCA and PCE mixtures proves that the phase transfer catalysts have the ability to increase oxidation rate of DNAPLs either in pure phase or mixtures and that there is significant potential for testing the catalyzed scheme under field conditions. Secondly, as an attempt to enhance the oxidation of DNAPL, we are trying to exploit cosolvency effects, utilizing various alcohol-water mixtures to increase DNAPL solubilization. Preliminary results of cosolvency experiments indicate the enhancement in the transfer of nonaqueous phase TCE to TBA-water solution and the rate of TCE degradation in aqueous phase.
Download or read book Technical and Regulatory Guidance for Surfactant cosolvent Flushing of DNAPL Source Zones written by and published by . This book was released on 2003 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of Potassium Permanganate Treatment of Pooled DNAPL written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
