Download or read book Biostimulation of Iron Reduction and Uranium Immobilization written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 3 CMEA Symposium on Biophysics of Nucleic Acids Structural and functional aaspects of nucleio acid protein interactions written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Idet written by and published by . This book was released on 1950 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reaction based Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This research sought to examine biogeochemical processes likely to take place in the less conductive materials above and below the gravel during the in situ ethanol biostimulation experiment conducted at Area 2 during 2005-2006. The in situ experiment in turn examined the hypothesis that injection of electron donor into this layer would induce formation of a redox barrier in the less conductive materials, resulting in decreased mass transfer of uranium out these materials and attendant declines in groundwater U(VI) concentration. Our project focuses on the development of a mechanistic understanding and quantitative models of coupled Fe(III)/U(VI) reduction in FRC Area 2 sediments. This report summarizes research activities conducted at The University of Central Florida (2004-2007), the development of biogeochemical and reactive transport models and the conduction of numerical simulations at laboratory, column, and field scales.

Download or read book Final Scientific Technical Report DE FG02 06ER64172 Reaction Based Reactive Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center Subproject to Co PI Eric E Roden written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes research conducted in conjunction with a project entitled "Reaction-Based Reactive Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center", which was funded through the Integrative Studies Element of the former NABIR Program (now the Environmental Remediation Sciences Program) within the Office of Biological and Environmental Research. Dr. William Burgos (The Pennsylvania State University) was the overall PI/PD for the project, which included Brian Dempsey (Penn State), Gour-Tsyh (George) Yeh (Central Florida University), and Eric Roden (formerly at The University of Alabama, now at the University of Wisconsin) as separately-funded co-PIs. The project focused on development of a mechanistic understanding and quantitative models of coupled Fe(III)/U(VI) reduction in FRC Area 2 sediments. The work builds on our previous studies of microbial Fe(III) and U(VI) reduction, and was directly aligned with the Scheibe et al. ORNL FRC Field Project at Area 2. Area 2 is a shallow pathway for migration of contaminated groundwater to seeps in the upper reach of Bear Creek at ORNL, mainly through a ca. 1 m thick layer of gravel located 4-5 m below the ground surface. The gravel layer is sandwiched between an overlying layer of disturbed fill material, and 2-3 m of undisturbed shale saprolite derived from the underlying Nolichucky Shale bedrock. The fill was put in place when contaminated soils were excavated and replaced by native saprolite from an uncontaminated area within Bear Creek Valley; the gravel layer was presumably installed prior to addition of the fill in order to provide a stable surface for the operation of heavy machinery. The undisturbed saprolite is highly weathered bedrock that has unconsolidated character but retains much of the bedding and fracture structure of the parent rock (shale with interbedded limestone). Hydrological tracer studies conducted during the Scheibe et al. field project indicate that the gravel layer receives input of uranium from both upstream sources and from diffusive mass transfer out of highly contaminated fill and saprolite materials above and below the gravel layer. This research sought to examine biogeochemical processes likely to take place in the less conductive materials above and below the gravel during the in situ ethanol biostimulation experiment conducted at Area 2 during 2005-2006. The in situ experiment in turn examined the hypothesis that injection of electron donor into this layer would induce formation of a redox barrier in the less conductive materials, resulting in decreased mass transfer of uranium out these materials and attendant declines in groundwater U(VI) concentration. Our research was directed toward the following three major objectives relevant to formation of this redox barrier: (1) elucidate the kinetics and mechanisms of reduction of solid-phase Fe(III) and U(VI) in Area 2 sediments; (2) evaluate the potential for long-term sustained U(IV) reductive immobilization in Area 2 sediments; (3) numerically simulate the suite of hydrobiogeochemical processes occurring in experimental systems so as to facilitate modeling of in situ U(IV) immobilization at the field-scale.

Download or read book Final Scientific Technical Report u2013 DE FG02 06ER64172 u2013 Reaction Based Reactive Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center u2013 Subproject to Co PI Eric E Roden written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes research conducted in conjunction with a project entitled ?Reaction-Based Reactive Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center?, which was funded through the Integrative Studies Element of the former NABIR Program (now the Environmental Remediation Sciences Program) within the Office of Biological and Environmental Research. Dr. William Burgos (The Pennsylvania State University) was the overall PI/PD for the project, which included Brian Dempsey (Penn State), Gour-Tsyh (George) Yeh (Central Florida University), and Eric Roden (formerly at The University of Alabama, now at the University of Wisconsin) as separately-funded co-PIs. The project focused on development of a mechanistic understanding and quantitative models of coupled Fe(III)/U(VI) reduction in FRC Area 2 sediments. The work builds on our previous studies of microbial Fe(III) and U(VI) reduction, and was directly aligned with the Scheibe and others ORNL FRC Field Project at Area 2. Area 2 is a shallow pathway for migration of contaminated groundwater to seeps in the upper reach of Bear Creek at ORNL, mainly through a circa 1 m thick layer of gravel located 4-5 m below the ground surface. The gravel layer is sandwiched between an overlying layer of disturbed fill material, and 2-3 m of undisturbed shale saprolite derived from the underlying Nolichucky Shale bedrock. The fill was put in place when contaminated soils were excavated and replaced by native saprolite from an uncontaminated area within Bear Creek Valley; the gravel layer was presumably installed prior to addition of the fill in order to provide a stable surface for the operation of heavy machinery. The undisturbed saprolite is highly weathered bedrock that has unconsolidated character but retains much of the bedding and fracture structure of the parent rock (shale with interbedded limestone). Hydrological tracer studies conducted during the Scheibe and others field project indicate that the gravel layer receives input of uranium from both upstream sources and from diffusive mass transfer out of highly contaminated fill and saprolite materials above and below the gravel layer. This research sought to examine biogeochemical processes likely to take place in the less conductive materials above and below the gravel during the in situ ethanol biostimulation experiment conducted at Area 2 during 2005-2006. The in situ experiment in turn examined the hypothesis that injection of electron donor into this layer would induce formation of a redox barrier in the less conductive materials, resulting in decreased mass transfer of uranium out these materials and attendant declines in groundwater U(VI) concentration. Our research was directed toward the following three major objectives relevant to formation of this redox barrier: (1) elucidate the kinetics and mechanisms of reduction of solid-phase Fe(III) and U(VI) in Area 2 sediments; (2) evaluate the potential for long-term sustained U(IV) reductive immobilization in Area 2 sediments; (3) numerically simulate the suite of hydrobiogeochemical processes occurring in experimental systems so as to facilitate modeling of in situ U(IV) immobilization at the field-scale.

Download or read book In Situ Immobilization of Uranium in Structured Porous Media Via Biomineralization at the Fraction Matrix Interface written by Eric E. Roden and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The major objectives of the University of Alabama component of this project are to (1) characterize the chemical composition (mainly iron and uranium abundance and redox speciation) of FRC Area 2 sediments; (2) assess the potential for stimulation of microbial Fe(III) and U(VI) reduction in slurries of Area 2 sediments; and (3) analyze the response of microbial community structure to biostimulation, specifically with regard to the abundance and diversity of dissimilatory metal-reducing bacterial (DMRB) populations. As an inclusive working hypothesis, we anticipate that it will be possible to stimulate microbial metal reduction in Area 2 sediment depth strata containing substantial quantities of Fe(III) oxides and U(VI), and that a major enrichment in known DMRB (e.g. Geobacteraceae and related organisms) will take place in response to biostimulation. Information on rates of microbial metabolism, patterns of Fe/U biotransformation, and microbial community response obtained in the slurry experiments will be used to constrain preliminary numerical simulations of the field-scale biostimulation experiment, and to provide molecular (e.g. 16S rRNA/rDNA) targets for assessing the response of DMRB activity to in situ biostimulation. Our progress to date on the above objectives is summarized.

Download or read book Uranium Immobilization Through Fe II Bio oxidation written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Current research on the bioremediation of heavy metals and radionuclides is focused on the ability of reducing organisms to use these metals as alternative electron acceptors in the absence of oxygen and thus precipitate them out of solution. However, many aspects of this proposed scheme need to be resolved, not the least of which is the time frame of the treatment process. Once treatment is complete and the electron donor addition is halted, the system will ultimately revert back to an oxic state and potentially result in the abiotic reoxidation and remobilization of the immobilized metals. In addition, the possibility exists that the presence of more electropositive electron acceptors such as nitrate or oxygen will also stimulate the biological oxidation and remobilization of these contaminants. The selective nitrate-dependent biooxidation of added Fe(II) may offer an effective means of "capping off" and completing the attenuation of these contaminants in a reducing environment making the contaminants less accessible to abiotic and biotic reactions and allowing the system to naturally revert to an oxic state. Our previous DOE-NABIR funded studies demonstrated that radionuclides such as uranium and cobalt are rapidly removed from solution during the biogenic formation of Fe(III)-oxides. In the case of uranium, X-ray spectroscopy analysis indicated that the uranium was in the hexavalent form (normally soluble) and was bound to the precipitated Fe(III)-oxides thus demonstrating the bioremediative potential of this process. We also demonstrated that nitrate-dependent Fe(II)- oxidizing bacteria are prevalent in the sediment and groundwater samples collected from sites 1 and 2 and the background site of the NABIR FRC in Oakridge, TN. However, all of these studies were performed in batch experiments in the laboratory with pure cultures and although a significant amount was learned about the microbiology of nitrate-dependent bio-oxidation of Fe(II), the effects of complex processes (such as advective flow) present in the natural environment are unknown. The objective of the current studies was to address some of these short-comings in an attempt to develop this bioremediative strategy into a robust, field applicable technology. This objective was approached by both pure culture studies investigating the mechanism of Fe(II) oxidation by nitrate reducing bacteria and examining the flow dynamics and microbial processes in advective flow columns amended with Fe(II) and nitrate over an extended period.

Download or read book A Numerical Study of Immobilization of Uranium by Iron written by Yong Wan and published by . This book was released on 2004 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effects of Bicarbonate and Mineral Surfaces on Uranium Immobilization Under Anaerobic Conditions written by Luis A. Jurado and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: For four decades, from 1940 through 1980, the U.S. Department of Energy (DoE) extensively mined and processed uranium at various sites. As a result, widespread uranium contamination exists in subsurface sediments and aquifers. In subsurface environments, uranium primarily exists as U(VI) or U(IV), oxidized and reduced species, respectively. U(VI) is highly soluble and toxic, U(IV), while relatively toxic, is insoluble which greatly reduces its exposure pathways. We seek to examine the role of ferric iron on U(VI) reduction by adsorbing U(VI) onto ferric and non-ferric mineral surfaces in the presence of a reductant. Further, we seek to understand the role that NaHCO3, a natural groundwater buffer, has in the reductive geochemical transformations of U(VI) adsorbed on ferric and non-ferric mineral surfaces. Bench top studies were performed using 100 uM U(VI) and the reductant AHQDS, in the presence and absence of Fe-Gel (amorphous ferric oxyhydroxide) and gamma-Al2O3. In the presence of a HEPES buffer at pH 8, results demonstrate direct homogeneous reduction in several hours in the absence of Fe-Gel or gamma-Al2O3, and reduction within a 48-hour period in the presence Fe-Gel or gamma-Al2O3. While adsorbed to both ferric and non-ferric mineral surfaces, U(VI) reduction is inhibited. U(VI) reduction in the presence of NaHCO3 buffer also inhibits U(VI) reduction.

Download or read book Gothaer B rgerbuch written by and published by . This book was released on 1910 with total page 515 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigating In Situ Bioremediation Approaches for Sustained Uranium Immobilization Independent of Nitrate Reduction written by David Balkwill and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The daunting prospect of complete nitrate removal at DOE sites, such as the ERSP Oak Ridge Field Research Center (FRC), provides strong incentive to explore bioremediation strategies that will allow for uranium bioreduction and long-term stabilization in the presence of nitrate. The cost and effort required for complete nitrate removal from the FRC and similar DOE-contaminated sites may prove to be unworkable. For example, field tests of uranium bioreduction at the FRC have shown that nitrate levels rebound quickly and completely after cessation of active biostimulation.

Download or read book Trace Elements in Waterlogged Soils and Sediments written by Jörg Rinklebe and published by CRC Press. This book was released on 2016-08-19 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many wetlands around the world act as sinks for pollutants, in particular for trace elements. In comparison to terrestrial environments, wetlands are still far less studied. A collaborative effort among world experts, this book brings the current knowledge concerning trace elements in temporary waterlogged soils and sediments together. It discusses factors controlling the dynamics and release kinetics of trace elements and their underlying biogeochemical processes. It also discusses current technologies for remediating sites contaminated with trace metals, and the role of bioavailability in risk assessment and regulatory decision making. This book is intended for professionals around the world in disciplines related to contaminant bioavailability in aquatic organisms, contaminant fate and transport, remediation technologies, and risk assessment of aquatic and wetland ecosystems.

Download or read book Reduction and Immobilization of Uranium in the Subsurface written by and published by . This book was released on 2015 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bio organic Amendments for Heavy Metal Remediation written by Allah Ditta and published by Elsevier. This book was released on 2024-07-23 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bio-organic Amendments for Heavy Metal Remediation: Water, soil and plant focuses on these core continuum media to explore remediation options using microbial, organic and combined approached. A volume in the Plant Biology, Sustainability and Climate Change series, this book offers a comprehensive view of techniques and approaches for addressing contamination by heavy metals.As anthropogenic activities increasingly negatively impact natural resources, there has been significant disturbance of water, soil, and plant continuum due to the accumulation of heavy metals. The bioaccumulation of heavy metals in the food chain could pose life-threatening effects on plants as well as humans, and there is need to find effective and sustainable remediation options. The application of bio-organic amendments could serve as a sustainable solution to this problem.Employing microbial, organic and combined approaches to reduce the accumulation of heavy metals in the food chain ultimately would lead to the production of safe food for humans.This book provides a comprehensive view of the challenge with a focus on the bioremediation of heavy metals contamination using ecotechnological approaches to protecting the soil, water and plant continuum. - Highlights remediation techniques/approaches for heavy metals under water, soil and plant continuums - Presents case-studies for real-world insights as well as current practices - Includes regulatory aspects for ensuring safe implementation

Download or read book Delivery and Mixing in the Subsurface written by Peter K. Kitanidis and published by Springer Science & Business Media. This book was released on 2012-04-23 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is meant to provide the practitioner with information on the natural mixing processes occurring in aquifers as well as to describe basic strategies that can be implemented to enhance mixing in particular cases. For example, when it comes to mixing miscible liquids, one can speed up mixing in the formation by manipulating the flow such as through the use of recirculation wells. Furthermore, much of the mixing can be achieved partially within recirculation wells themselves, where contaminated water is admixed with additives, volatile products may be removed through a vapor mass exchanger, etc. Thus, adding mixing wells can significantly increase the performance of the delivery and mixing system and speed up the process of remediation.

Download or read book Microbially Mediated Reduction and Immobilization of Uranium in Aquifers at Konigstein Germany Using Indigenous Bacteria written by Zhu Chen and published by . This book was released on 2001 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: