Download Free Abiotic Transformation Of Trichloroethylene In The Gas Phase By Elemental Iron Book in PDF and EPUB Free Download. You can read online Abiotic Transformation Of Trichloroethylene In The Gas Phase By Elemental Iron and write the review.

Biogeochemical reactions promoted by reactive mineral species and bacteria in sediment and groundwater influence the fate of environmental contaminants. Enhanced reductive transformations of chlorinated ethenes, a class of persistent contaminants, have been observed in biologically active systems relative to analogous abiotic systems. While some reactions mediated by bacteria are more efficient than abiotic reactions, biological dechlorination of chlorinated ethenes can yield byproducts that are no less toxic than the original contaminant. Chlorinated ethenes are remarkably challenging to remediate in aquifers with low permeability zones (LPZs), such as silts and clays. This dissertation explores the biotic and abiotic contributions to trichloroethene (TCE) transformation during back diffusion from LPZs into adjacent high permeability zones (HPZs). These contributions are quantified with flow cell experiments that represent the LPZ/HPZ interface using clay and sand from a field site. Flow cell data informed development of a numerical diffusion-reaction model, and back diffusion during biotic and abiotic TCE transformation was simulated. Both pathways occurred simultaneously in the flow cell, with biotic processes transforming more TCE mass than abiotic processes in the presence of electron donor. Simulations constrained to abiotic reactions demonstrated that reactive minerals can decrease TCE flux from LPZs by 2-53% over two years, depending on the mineral type. TCE attenuation of this magnitude highlights the potential for abiotic transformations in some contaminated aquifers. Other biologically mediated reductive reactions promote formation of minerals that abiotically transform TCE to innocuous compounds. The role of both sulfate and iron reducing bacteria in forming and maintaining reactive iron sulfide minerals was evaluated. Reduction potential significantly influenced TCE transformation kinetics, with more negative potentials correlating with more iron sulfide precipitation and higher TCE transformation rates. Coprecipitation of other mineral species at less negative potentials contributed to diminished TCE transformation. XPS and XRD data paired with MINTEQ calculations informed conclusions about experimental precipitate reactivity. Prior to this work, no study had shown that mineral-promoted abiotic reactions could attenuate TCE in LPZs. It is also the first time that correlations between redox potential, mineral stability, and TCE transformation kinetics have been evaluated for biogenic iron sulfides with varied iron concentrations
This is the first complete edited volume devoted to providing comprehensive and state-of-the art descriptions of science principles and pilot- and field-scaled engineering applications of nanoscale zerovalent iron particles (NZVI) for soil and groundwater remediation. Although several books on environmental nanotechnology contain chapters of NZVI for environmental remediation (Wiesner and Bottero (2007); Geiger and Carvalho-Knighton (2009); Diallo et al. (2009); Ram et al. (2011)), none of them include a comprehensive treatment of the fundamental and applied aspects of NZVI applications. Most devote a chapter or two discussing a contemporary aspect of NZVI. In addition, environmental nanotechnology has a broad audience including environmental engineers and scientists, geochemists, material scientists, physicists, chemists, biologists, ecologists and toxicologists. None of the current books contain enough background material for such multidisciplinary readers, making it difficult for a graduate student or even an experienced researcher or environmental remediation practitioner new to nanotechnology to catch up with the massive, undigested literature. This prohibits the reader from gaining a complete understanding of NZVI science and technology. In this volume, the sixteen chapters are based on more than two decades of laboratory research and development and field-scaled demonstrations of NZVI implementation. The authors of each chapter are leading researchers and/or practitioners in NZVI technology. This book aims to be an important resource for all levels of audiences, i.e. graduate students, experienced environmental and nanotechnology researchers, and practitioners evaluating environmental remediation, as it is designed to involve everything from basic to advanced concepts.
A complete restructuring and updating of the classic 1982 Handbook of Chemical Property Estimation Methods (commonly known as "Lyman's Handbook"), the Handbook of Property Estimation Methods for Chemicals: Environmental and Health Sciences reviews and recommends practical methods for estimating environmentally important properties of organic chemic
Bioavailability refers to the extent to which humans and ecological receptors are exposed to contaminants in soil or sediment. The concept of bioavailability has recently piqued the interest of the hazardous waste industry as an important consideration in deciding how much waste to clean up. The rationale is that if contaminants in soil and sediment are not bioavailable, then more contaminant mass can be left in place without creating additional risk. A new NRC report notes that the potential for the consideration of bioavailability to influence decision-making is greatest where certain chemical, environmental, and regulatory factors align. The current use of bioavailability in risk assessment and hazardous waste cleanup regulations is demystified, and acceptable tools and models for bioavailability assessment are discussed and ranked according to seven criteria. Finally, the intimate link between bioavailability and bioremediation is explored. The report concludes with suggestions for moving bioavailability forward in the regulatory arena for both soil and sediment cleanup.
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.
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 Envir- mental Response, Compensation, and Liability Act (CERCLA), commonly known as Sup- fund, 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 techn- ogies for cleaning up contaminated sites were wildly optimistic. Original estimates, in 1980, projected an average Superfund cleanup cost of a mere $3.
The oceans and atmosphere interact through various processes, including the transfer of momentum, heat, gases and particles. In this book leading international experts come together to provide a state-of-the-art account of these exchanges and their role in the Earth-system, with particular focus on gases and particles. Chapters in the book cover: i) the ocean-atmosphere exchange of short-lived trace gases; ii) mechanisms and models of interfacial exchange (including transfer velocity parameterisations); iii) ocean-atmosphere exchange of the greenhouse gases carbon dioxide, methane and nitrous oxide; iv) ocean atmosphere exchange of particles and v) current and future data collection and synthesis efforts. The scope of the book extends to the biogeochemical responses to emitted / deposited material and interactions and feedbacks in the wider Earth-system context. This work constitutes a highly detailed synthesis and reference; of interest to higher-level university students (Masters, PhD) and researchers in ocean-atmosphere interactions and related fields (Earth-system science, marine / atmospheric biogeochemistry / climate). Production of this book was supported and funded by the EU COST Action 735 and coordinated by the International SOLAS (Surface Ocean- Lower Atmosphere Study) project office.