Download or read book Microbial Controls on Contaminant Metal Transport in Porous Media written by Leon Kapetas and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal contamination in groundwater aquifers poses risks to human health as well as other life forms. Previous laboratory experiments have demonstrated that bacteria found in geologic settings like aquifers are likely to adsorb metal contaminants and attenuate metal migration. However, as bacteria can also migrate through the groundwater aquifer a better understanding of the combined effect of these two processes is required. The aim of this laboratory study was to a) explore the affinity bacteria exhibit towards metals and porous media of varying composition, b) investigate the effect of mineral and solution composition on the bacterial filtration and c) use the combined data to predict the impact of microbes on metal mobility in porous media. Pantoea Agglomerans was used as a model bacterium while column materials consisted of quartz sand and iron-oxide coated sand (IOCS). Bacteria were characterised using potentiometric titrations to identify the type and concentration of sites present on their bacterial wall. Particular attention was paid to the effect of kinetics of proton and metal adsorption due to the variable contact times that solutions have with bacteria in columns. It was found that increasing the contact time between cell surfaces and protons during potentiometric titrations resulted in less reproducible results. This was due to the release of cell exudates under high pH conditions rather than cell death. Exudates were also found to adsorb protons. Moreover, zinc adsorption onto cell surfaces is higher after 60 to 90 minutes of contact time, while there is a decline in adsorption for longer contact times due to release of cell exudates in the solution. Stability constants for the adsorption of zinc onto cell surface sites, quartz and IOCS materials were determined through batch adsorption experiments, providing a mechanistic explanation of the adsorption process. Reactive transport models incorporating kinetics and surface complexation are developed to describe zinc movement through packed columns. Batch kinetic studies showed that significant Zn sorption to IOCS takes place gradually during the first two hours of contact time. Adsorption continues to take place at a slower rate for an additional 10 hours. This kinetic effect is manifested also during flow-through experiments (column dimensions: length 0.12 m, diameter 0.025 m) with a Darcian velocity 6.1·10-3 cm s-1, which is comparable to natural groundwater flow rates through sand porous media. A pseudo-second order kinetic adsorption model is combined with a numerical advection dispersion model for the first time to predict Zn transport. Model output results are of mixed quality as the model cannot successfully describe contaminant arrival time and breakthrough curve shape simultaneously. Moreover, a mechanistic surface complexation reactive transport model is capable of predicting Zn sorption under varying pH conditions demonstrating the versatility of mechanistic models. However, these models do not account for kinetics and therefore they are not intended to fit the dispersion of the contaminant due to kinetic effects of adsorption. Experiments in mixed zinc/cell systems demonstrate that transport through IOCS is dominated by the adsorption to the porous medium. This is consistent with the batch surface complexation predictions for the system. Adsorption to bacteria is reversible and zinc is stripped from the cells and redistributed onto the IOCS. Adsorption onto cells becomes significant and plays a role in mobile metal speciation only once the column is saturated with zinc.
Download or read book Modeling Bacteria Facilitated Contaminant Transport in Porous Media written by Seung Hyun Kim and published by . This book was released on 1995 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transport Processes in Porous Media written by Jacob Bear and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 807 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the invited lectures presented during the NATO/ASI conducted in Pullman, Washington, July 9-18, 1989. This is the third in a series of NATO/ASIs on transport phenomena in porous media. The first two, which took place at Newark, Delaware in 1982 and 1985, are devoted to various topics related to the Fundamentals of Transport Processes in Porous Media. The contents of the books resulting from previous NATO/ASIs are given at the end of this book. Transport of extensive quantities such as mass of a fluid phase, mass of chemical species carried by a fluid phase, energy and electric charge in porous media, as encountered in a large variety of engineering disciplines, is an emerging interdisciplinary field. The groundwater flow, the simultaneous flow of gas, oil and water in petroleum reservoirs, the movement and accumulation of pollutants in the saturated and unsaturated subsurface zones, thermal energy storage in reservoirs, land subsidence in response to charges in overburden loads, or to pumping of fluids from underground formations, wave propagation in seismic investigations or as produced by earthquakes, chemical reactors, water flow through sand filters and the movement of fluids through kidneys, may serve as examples of fields in which the theory of transport in porous media is employed.
Download or read book Handbook of Metal Microbe Interactions and Bioremediation written by Surajit Das and published by CRC Press. This book was released on 2017-04-07 with total page 813 pages. Available in PDF, EPUB and Kindle. Book excerpt: Around the World, metal pollution is a major problem. Conventional practices of toxic metal removal can be ineffective and/or expensive, delaying and exacerbating the crisis. Those communities dealing with contamination must be aware of the fundamentals advances of microbe-mediated metal removal practices because these methods can be easily used and require less remedial intervention. This book describes innovations and efficient applications for metal bioremediation for environments polluted by metal contaminates.
Download or read book Dynamics of Coupled Contaminant and Microbial Transport in Heterogeneous Porous Media 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: Dynamic microbial attachment/detachment occurs in subsurface systems in response to changing environmental conditions caused by contaminant movement and degradation. Understanding the environmental conditions and mechanisms by which anaerobic bacteria partition between aqueous and solid phases is a critical requirement for designing and evaluating in-situ bioremediation efforts. This interdisciplinary research project will provide fundamental information on the attachment/detachment dynamics of anaerobic bacteria in heterogeneous porous media under growth and growth-limiting conditions. Experiments will provide information on passive and active attachment/detachment mechanisms used by growing anaerobes capable of reductive dechlorination. Theoretical representations of these attachment/detachment mechanisms will be incorporated into existing flow and transport models that incorporate heterogeneity effects and can be used to predict behavior at field scales. These mechanistic-based models will be tested against experimental data provided through controlled laboratory experiments in heterogeneous porous media in large (meter-scale) 2-D flow cells. In addition to a mechanistic-based predictive model, this research will lead to new theories for the transient spatial distribution of microbial populations and contaminant plumes in heterogeneous porous media, improving the capability for designing staged remediation strategies for dealing with mixed contaminants.
Download or read book Dynamics of Coupled Contaminant and Microbial Transport in Heterogeneous Porous Media 1997 Annual Progress Report written by and published by . This book was released on 1997 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic microbial attachment/detachment occurs in subsurface systems in response to changing environmental conditions caused by contaminant movement and degradation. Understanding the environmental conditions and mechanisms by which anaerobic bacteria partition between aqueous and solid phases is a critical requirement for designing and evaluating in situ bioremediation efforts. This interdisciplinary research project will provide fundamental information on the attachment/detachment dynamics of anaerobic bacteria in heterogeneous porous media under growth and growth-limiting conditions. Experiments will provide information on passive and active attachment/detachment mechanisms used by growing anaerobes capable of reductive dechlorination. Theoretical representations of these attachment/detachment mechanisms will be incorporated into existing groundwater flow and contaminant transport models that incorporate heterogeneity effects and can be used to predict behavior at field scales. These mechanistic-based models will be tested against experimental data provided through controlled laboratory experiments in heterogeneous porous media in large (meter-scale) 2-D flow cells. In addition to a mechanistic-based predictive model, this research will lead to new theories for the transient spatial distribution of microbial populations and contaminant plumes in heterogeneous porous media, improving the capability for designing staged remediation strategies for dealing with mixed contaminants.
Download or read book Reactive Transport in Porous Media written by Peter C. Lichtner and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 34 of Reviews in Mineralogy focuses on methods to describe the extent and consequences of reactive flow and transport in natural subsurface systems. Since the field of reactive transport within the Earth Sciences is a highly multidisciplinary area of research, including geochemistry, geology, physics, chemistry, hydrology, and engineering, this book is an attempt to some extent bridge the gap between these different disciplines. This volume contains the contributions presented at a short course held in Golden, Colorado, October 25-27, 1996 in conjunction with the Mineralogical Society of America's (MSA) Annual Meeting with the Geological Society of America in Denver, Colorado.
Download or read book Microbial Extracellular Polymeric Substances written by Jost Wingender and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial extracellular polymeric substances (EPS) are the key components for the aggregation of microorganisms in biofilms, flocs and sludge. They are composed of polysaccharides, proteins, nucleic acids, lipids and other biological macromolecules. EPS provide a highly hydrated gel matrix in which microbial cells can establish stable synergistic consortia. Cohesion and adhesion as well as morphology, structure, biological function and other properties such as mechanical stability, diffusion, sorption and optical properties of microbial aggregates are determined by the EPS matrix. Also, the protection of biofilm organisms against biocides is attributed to the EPS. Their matrix allows phase separation in biofiltration and is also important for the degradation of particulate material which is of great importance for the self purification processes in surface waters and for waste water treatment.
Download or read book Issue Paper on the Environmental Chemistry of Metals written by and published by . This book was released on 2004 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fate Transport and Interactions of Metals written by and published by . This book was released on 1995 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1991 with total page 962 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamics of Coupled Microbial and Contaminant Transport written by and published by . This book was released on 2000 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic microbial attachment/detachment occurs in subsurface systems in response to changing environmental conditions caused by contaminant movement and degradation. This project's objective is to develop the understanding of the environmental conditions and mechanisms by which anaerobic bacteria partition between aqueous and solid phases. In particular this interdisciplinary research project provides fundamental information on the attachment/detachment dynamics of anaerobic bacteria in heterogeneous porous media under growth and growth-limiting conditions. This is a critical requirement for designing and evaluating in situ bioremediation efforts.
Download or read book Bioavailability of Contaminants in Soils and Sediments written by National Research Council and published by National Academies Press. This book was released on 2003-05-03 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Research in Progress FY 1992 written by United States. Department of Energy. Office of Health and Environmental Research and published by . This book was released on 1993 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microbial Transport in Porous Media written by David Andrew Jennings and published by . This book was released on 1994 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mobilization of Metals in Soils by a Bacterial Extracellular Polymer written by Anna S. Spaulding and published by . This book was released on 2005 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Good Practices for Preventing Microbial Contamination of Water Mains Field Pocket Guide written by Gregory J. Kirmeyer and published by . This book was released on 2014 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt:
