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Stabilization of Plutonium in Subsurface Environments via Microbial Reduction and Biofilm Formation

Description: Plutonium has a long half-life (2.4 x 104 years) and is of concern because of its chemical and radiological toxicity, high-energy alpha radioactive decay. A full understanding of its speciation and interactions with environmental processes is required in order to predict, contain, or remediate contaminated sites. Under aerobic conditions Pu is sparingly soluble, existing primarily in its tetravalent oxidation state. To the extent that pentavalent and hexavalent complexes and small colloidal species form they will increase the solubility and resultant mobility from contamination sources. There is evidence that in both marine environments and brines substantial fractions of the plutonium in solution is present as hexavalent plutonyl, PuO2 2+.
Date: April 19, 2007
Creator: Boukhalfa, Hakim; Icopini, Gary A.; Reilly, Sean D. & Neu, Mary P.
Partner: UNT Libraries Government Documents Department

Annual progress Report on research related to our research project “Stabilization of Plutonium in Subsurface Environments via Microbial Reduction and Biofilm Formation” funded by the Environmental Remediation Sciences Division (ERSD)

Description: The overarching goal of this research project is to investigate and optimize the mechanisms for in situ immobilization of Pu species by naturally-occurring bacteria. Specific research objectives are: (a) investigate the mechanism of bacterial accumulation and immobilization of plutonium species by biofilm formation under aerobic conditions and (b) to demonstrate the direct and indirect stabilization of Pu via dissimilatory reduction by Geobacter metallireducens.
Date: June 1, 2006
Creator: New, Mary
Partner: UNT Libraries Government Documents Department

In situ global method for measurement of oxygen demand and mass transfer

Description: Two aerobic microorganisms, Saccharomycopsis lipolytica and Brevibacterium lactofermentum, have been used in a study of mass transfer and oxygen uptake from a global perspective using a closed gas system. Oxygen concentrations in the gas and liquid were followed using oxygen electrodes, and the results allowed for easy calculation of in situ oxygen transport. The cell yields on oxygen for S. lipolytica and B. lactofermentum were 1.01 and 1.53 g/g respectively. The mass transfer coefficient was estimated as 10 h{sup {minus}1} at 500 rpm for both fermentations. The advantages with this method are noticeable since the use of model systems may be avoided, and the in situ measurements of oxygen demand assure reliable data for scale-up.
Date: May 1, 1997
Creator: Klasson, K.T.; Lundbaeck, K.M.O.; Clausen, E.C. & Gaddy, J.L.
Partner: UNT Libraries Government Documents Department

The utilization of the microflora indigenous to and present in oil-bearing formations to selectively plug the more porous zones thereby increasing oil recovery during waterflooding. Annual report, January 1, 1996--December 30, 1996

Description: This project is a field demonstration of the ability of in-situ indigenous microorganisms in the North Blowhorn Creek Oil Field to reduce the flow of injection water in the more permeable zones thereby diverting flow to other areas of the reservoir and thus increase the efficiency of the waterflooding operation. This effect is to be accomplished by adding microbial nutrients to the injection water. Work on the project is divided into three phases, Planning and Analysis (9 months), Implementation (45 months), and Technology Transfer (12 months). This report covers the third year of work on the project. During Phase I, two wells were drilled in an area of the field where approximately twenty feet of Carter sand were found and appeared to contain oil bypassed by the existing waterflood. Cores from one well were obtained and used in laboratory core flood experiments. The schedule and amounts of nutrients to be employed in the field were formulated on the basis of the results from laboratory core flood experiments.
Date: August 1, 1997
Creator: Brown, L.R. & Vadie, A.A.
Partner: UNT Libraries Government Documents Department

Summary report on the aerobic degradation of diesel fuel and the degradation of toluene under aerobic, denitrifying and sulfate reducing conditions

Description: This report contains a number of studies that were performed to better understand the technology of the biodegradation of petroleum hydrocarbons. Topics of investigation include the following: diesel fuel degradation by Rhodococcus erythropolis; BTEX degradation by soil isolates; aerobic degradation of diesel fuel-respirometry; aerobic degradation of diesel fuel-shake culture; aerobic toluene degradation by A3; effect of HEPES, B1, and myo-inositol addition on the growth of A3; aerobic and anaerobic toluene degradation by contaminated soils; denitrifying bacteria MPNs; sulfate-reducing bacteria MPNs; and aerobic, DNB and SRB enrichments.
Date: August 15, 1995
Creator: Coyne, P. & Smith, G.
Partner: UNT Libraries Government Documents Department

On-line monitoring of aerobic bioremediation with bioluminescent reporter microbes. Final report, July 1991--December 1994

Description: A critical issue in the biological characterization of contaminated sites and in the evaluation of relative bioremediation treatment efficiencies is the development of appropriate monitoring methods for the assessment of pollutant bioavailability and microbial in situ activity potential. In nature, pollutants are found dispersed among the solid, liquid and gaseous phases of the complex environments rendering the analytical estimation of their bioavailability and degradation more difficult and irrelevant. Ex situ and extractive analytical techniques have only been misrepresentative of the natural conditions and often resulted in inaccurate estimates of pollutants mass transfer. In this project, the bioluminescent bioreporter bacterium P. Fluorescens HK44 was integrated to an optical device, capable of conducting emitted light, and used as an online biosensor of naphthalene and salicylate. The physiological requirements of the bacteria and the physical limitations of the biosensor were also determined.
Date: March 1, 1995
Creator: Sayler, G. S.
Partner: UNT Libraries Government Documents Department


Description: Burial of amine reclaimer unit sludges and system filters has resulted in contamination of soil at the CanOxy Okotoks decommissioned sour gas-processing plant with amines, amine byproducts, and salts. A three-phase research program was devised to investigate the natural attenuation process that controls the subsurface transport and fate of these contaminants and to apply the results toward the development of a strategy for the remediation of this type of contamination in soils. Phase I experimental activities examined interactions between monoethanolamine (MEA) and sediment, the biodegradability of MEA in soils at various concentrations and temperatures, and the biodegradability of MEA sludge contamination in a soil slurry bioreactor. The transport and fate of MEA in the subsurface was found to be highly dependant on the nature of the release, particularly MEA concentration and conditions of the subsurface environment, i.e., pH, temperature, and oxygen availability. Pure compound biodegradation experiments in soil demonstrated rapid biodegradation of MEA under aerobic conditions and moderate temperatures (>6 C). Phase II landfarming activities confirmed that these contaminants are readily biodegradable in soil under ideal laboratory conditions, yet considerable toxicity was observed in the remaining material. Examination of water extracts from the treated soil suggested that the toxicity is water-soluble. Phase II activities led to the conclusion that landfarming is not the most desirable bioremediation technique; however, an engineered biopile with a leachate collection system could remove the remaining toxic fraction from the soil. Phase III was initiated to conduct field-based experimental activities to examine the optimized remediation technology. A pilot-scale engineered biopile was constructed at a decommissioned gas-sweetening facility in Okotoks, Alberta, Canada. On the basis of a review of the analytical and performance data generated from soil and leachate samples, the biopile operation has successfully removed all identified amines and removed significant amounts of organic nitrogen and ...
Date: May 1, 2000
Creator: Sorensen, James A.; Gallagher, John R. & Kays, Lori G.
Partner: UNT Libraries Government Documents Department

Whole-Genome Transcriptional Analysis of Chemolithoautotrophic Thiosulfate Oxidation by Thiobacillus denitrificans Under Aerobic vs. Denitrifying Conditions

Description: Thiobacillus denitrificans is one of the few known obligate chemolithoautotrophic bacteria capable of energetically coupling thiosulfate oxidation to denitrification as well as aerobic respiration. As very little is known about the differential expression of genes associated with ke chemolithoautotrophic functions (such as sulfur-compound oxidation and CO2 fixation) under aerobic versus denitrifying conditions, we conducted whole-genome, cDNA microarray studies to explore this topic systematically. The microarrays identified 277 genes (approximately ten percent of the genome) as differentially expressed using Robust Multi-array Average statistical analysis and a 2-fold cutoff. Genes upregulated (ca. 6- to 150-fold) under aerobic conditions included a cluster of genes associated with iron acquisition (e.g., siderophore-related genes), a cluster of cytochrome cbb3 oxidase genes, cbbL and cbbS (encoding the large and small subunits of form I ribulose 1,5-bisphosphate carboxylase/oxygenase, or RubisCO), and multiple molecular chaperone genes. Genes upregulated (ca. 4- to 95-fold) under denitrifying conditions included nar, nir, and nor genes (associated respectively with nitrate reductase, nitrite reductase, and nitric oxide reductase, which catalyze successive steps of denitrification), cbbM (encoding form II RubisCO), and genes involved with sulfur-compound oxidation (including two physically separated but highly similar copies of sulfide:quinone oxidoreductase and of dsrC, associated with dissimilatory sulfite reductase). Among genes associated with denitrification, relative expression levels (i.e., degree of upregulation with nitrate) tended to decrease in the order nar > nir > nor > nos. Reverse transcription, quantitative PCR analysis was used to validate these trends.
Date: April 22, 2006
Creator: Beller, H R; Letain, T E; Chakicherla, A; Kane, S R; Legler, T C & Coleman, M A
Partner: UNT Libraries Government Documents Department

Spectral induced polarization and electrodic potential monitoring of microbially mediated iron sulfide transformations

Description: Stimulated sulfate-reduction is a bioremediation technique utilized for the sequestration of heavy metals in the subsurface.We performed laboratory column experiments to investigate the geoelectrical response of iron sulfide transformations by Desulfo vibriovulgaris. Two geoelectrical methods, (1) spectral induced polarization (SIP), and (2) electrodic potential measurements, were investigated. Aqueous geochemistry (sulfate, lactate, sulfide, and acetate), observations of precipitates (identified from electron microscopy as iron sulfide), and electrodic potentials on bisulfide ion (HS) sensitive silver-silver chloride (Ag-AgCl) electrodes (630 mV) were diagnostic of induced transitions between an aerobic iron sulfide forming conditions and aerobic conditions promoting iron sulfide dissolution. The SIP data showed 10m rad anomalies during iron sulfide mineralization accompanying microbial activity under an anaerobic transition. These anomalies disappeared during iron sulfide dissolution under the subsequent aerobic transition. SIP model parameters based on a Cole-Cole relaxation model of the polarization at the mineral-fluid interface were converted to (1) estimated biomineral surface area to pore volume (Sp), and (2) an equivalent polarizable sphere diameter (d) controlling the relaxation time. The temporal variation in these model parameters is consistent with filling and emptying of pores by iron sulfide biofilms, as the system transitions between anaerobic (pore filling) and aerobic (pore emptying) conditions. The results suggest that combined SIP and electrodic potential measurements might be used to monitor spatiotemporal variability in microbial iron sulfide transformations in the field.
Date: February 15, 2008
Creator: Hubbard, Susan; Personna, Y.R.; Ntarlagiannis, D.; Slater, L.; Yee, N.; O'Brien, M. et al.
Partner: UNT Libraries Government Documents Department

Evaluation of the effects of various culture condition on Cr (VI) reduction by Shewanella oneidensis MR-1 in a novel high-throughputmini-bioreactor

Description: The growth and Cr(VI) reduction by Shewanella oneidensisMR-1 was examined using a mini-bioreactor system that independentlymonitors and controls pH, dissolved oxygen, and temperature for each ofits 24, 10-mL reactors. Independent monitoring and control of eachreactor in the cassette allows the exploration of a matrix ofenvironmental conditions known to influence S. oneidensis chromiumreduction. S. oneidensis MR-1 grew in minimal medium without amino acidor vitamin supplementation under aerobic conditions but required serineand glycine supplementation under anaerobic conditions. Growth wasinhibited by dissolved oxygen concentrations>80 percent. Lactatetransformation to acetate was enhanced by low concentration of dissolvedoxygen during the logarithmic growth phase. Between 11 and 35oC, thegrowth rate obeyed the Arrhenius reaction rate-temperature relationship,with a maximum growth rate occurring at 35oC. S. oneidensis MR-1 was ableto grow over a wide range of pH (6-9). At neutral pH and temperaturesranging from 30-35oC, S. oneidensis MR-1 reduced 100 mu M Cr(VI) toCr(III) within 20 minutes in the exponential growth phase, and the growthrate was not affected by the addition of chromate; it reduced chromateeven faster at temperatures between 35 and 39oC. At low temperatures(<25oC), acidic (pH<6.5), or alkaline (pH>8.5) conditions, 100mu M Cr(VI) strongly inhibited growth and chromate reduction. Themini-bioreactor system enabled the rapid determination of theseparameters reproducibly and easily by performing very few experiments.Besides its use for examining parameters of interest to environmentalremediation, the device will also allow one to quickly assess parametersfor optimal production of recombinant proteins or secondarymetabolites
Date: March 16, 2006
Creator: Tang, Yinjie J.; Laidlaw, David; Gani, Kishen & Keasling, Jay D.
Partner: UNT Libraries Government Documents Department

Association of N2-fixing cyanobacteria and plants: towards novel symbioses of agricultural importance

Description: Some nitrogen-fixing cyanobacteria are able to form symbioses with a wide variety of plants. Nostoc 2S9B is unusual in its ability to infect the roots of wheat, raising the prospect of a productive association with an important crop plant. The goal of the project was to lay the groundwork for the use of novel associations between Nostoc and crops of agronomic importance, thereby reducing our reliance on nitrogenous fertilizer. Nostoc 2S9B was found to enter roots through mechanical damage of roots and reside primarily in intercellular spaces. The strain could also be incorporated into wheat calli grown in tissue culture. In both cases, the rate of nitrogen fixation by the cyanobacterium was higher than that of the same strain grown with no plant present. Artificial nodules induced by the action of hormone 2,4D were readily infected by Nostoc 2S9B, and the cyanobacteria within such nodules fixed nitrogen under fully aerobic conditions. The nitrogen fixed was shown to be incorporated into the growing wheat seedlings. Nostoc thus differs from other bacteria in its ability to fix nitrogen in para-nodules without need for artificially microaerobic conditions. It would be useful to introduce foreign DNA into Nostoc 2S9B in order to make defined mutations to understand the genetic basis of its ability to infect wheat and to create strains that might facilitate the study of the infection process. Transfer of DNA into the cyanobacterium appears to be limited by the presence of four restriction enzymes, with recognition sequences the same as BamHI, BglI, BsaHI, and Tth111I. Genes encoding methyltransferases that protect DNA against these four enzymes have been cloned into helper plasmids to allow transfer of DNA from E. coli to Nostoc 2S9B.
Date: June 25, 2001
Creator: Elhai, Jeff
Partner: UNT Libraries Government Documents Department

Molecular characterization of bacterial respiration on minerals. Final technical report, August 4, 1994--August 3, 1996

Description: The scope of work outlined in the original proposal contained two specific aims. Highlights of the results obtained and published on each specific aim during the grant period in question are summarized. The first aim continued the identification, separation, and characterization of the cellular components necessary for aerobic respiration on iron. An electrochemical apparatus for the large scale cultivation of chemolithotrophic bacteria that respire aerobically on ferrous ions was perfected. The kinetic properties of an acid-stable iron:rusticyanin oxidoreductase from T. ferrooxidans were determined. The overall tertiary structure of rusticyanin in solution was elucidated from a combination of homonuclear proton and heteronuclear {sup 15}N-edited NMR spectra. An artificial gene for rusticyanin was designed, synthesized, and successfully expressed in E. coli. The X-ray crystallographic structure of rusticyanin was solved to a resolution of 1.9 {angstrom} by multiwavelength anomalous dispersion (MAD) phasing. The second aim initiated an investigation of the molecular principles whereby these bacteria recognize and adhere to their insoluble inorganic substrates. The electrophoretic mobility of T. ferrooxidans with and without its insoluble substrates was determined by laser Doppler velocimetry under physiological conditions. The adherence of T. ferrooxidans to the surface of pyrite was observed directly in a video-enhanced light microscope.
Date: December 31, 1996
Creator: Blake, R. II
Partner: UNT Libraries Government Documents Department

Results an data on the growth of the microorganisms

Description: The study of biocorrosion of aluminum and its alloy was performed under conditions of continuous fermentation of thermophilic anaerobic microorganisms of different groups. This allowed us to examine the effect of various types of metabolic reactions of reduction-oxidation proceeding at different pH and temperatures under highly reduced conditions on aluminum corrosion. Besides, the experiments were performed where the part of the standard sample was exposed under strictly anaerobic conditions with an active microbiological process, and the second half was exposed under aerobic conditions. Thus the sample was exposed in gradient of oxidized-reduced conditions.
Date: October 9, 1995
Creator: Laurinavichius, K.S.
Partner: UNT Libraries Government Documents Department

Molecular characterization of bacterial respiration of minerals. Final technical report, March 1, 1985--February 29, 1996

Description: The goals of this project were to continue the identification, separation, and characterization of the cellular components necessary for aerobic respiration on iron, and to initiate an investigation of the molecular principles whereby these bacteria recognize and adhere to their insoluble inorganic substrates. Progress is described.
Date: August 1, 1996
Creator: Blake, R. II
Partner: UNT Libraries Government Documents Department

Mathematical modeling of the effects of aerobic and anaerobic chelate bioegradation on actinide speciation.

Description: Biodegradation of natural and anthropogenic chelating agents directly and indirectly affects the speciation, and, hence, the mobility of actinides in subsurface environments. We combined mathematical modeling with laboratory experimentation to investigate the effects of aerobic and anaerobic chelate biodegradation on actinide [Np(IV/V), Pu(IV)] speciation. Under aerobic conditions, nitrilotriacetic acid (NTA) biodegradation rates were strongly influenced by the actinide concentration. Actinide-chelate complexation reduced the relative abundance of available growth substrate in solution and actinide species present or released during chelate degradation were toxic to the organisms. Aerobic bio-utilization of the chelates as electron-donor substrates directly affected actinide speciation by releasing the radionuclides from complexed form into solution, where their fate was controlled by inorganic ligands in the system. Actinide speciation was also indirectly affected by pH changes caused by organic biodegradation. The two concurrent processes of organic biodegradation and actinide aqueous chemistry were accurately linked and described using CCBATCH, a computer model developed at Northwestern University to investigate the dynamics of coupled biological and chemical reactions in mixed waste subsurface environments. CCBATCH was then used to simulate the fate of Np during anaerobic citrate biodegradation. The modeling studies suggested that, under some conditions, chelate degradation can increase Np(IV) solubility due to carbonate complexation in closed aqueous systems.
Date: March 19, 1998
Creator: Banaszak, J.E.; VanBriesen, J.; Rittmann, B.E. & Reed, D.T.
Partner: UNT Libraries Government Documents Department

Involvement of Linear Plasmids in Aerobic Biodegradation of Vinyl Chloride

Description: Pseudomonas putida strain AJ and Ochrobactrum strain TD were isolated from hazardous waste sites based on their ability to use vinyl chloride (VC) as a sole source of carbon and energy under aerobic conditions. Strains AJ and TD also use ethene and ethylene oxide as growth substrates. Strain AJ contained a linear megaplasmid (approximately 260 kb) when grown on VC or ethene, but no circular plasmids. While growing on ethylene oxide, the size of the linear plasmid in strain AJ decreased to approximately 100 kb, although its ability to use VC as a substrate was retained. The linear plasmids in strain AJ were cured and its ability to consume VC, ethene, and ethylene oxide was lost following growth on a rich substrate (Luria-Bertani broth) through at least three transfers. Strain TD contained three linear plasmids, ranging in size from approximately 100 kb to 320 kb, when growing on VC or ethene. As with strain AJ, the linear plasmids in strain TD were cured following growth on Luria -Bertani broth and its ability to consume VC and ethene was lost. Further analysis of these linear plasmids may help reveal the pathway for VC biodegradation in strains AJ and TD and explain why this process occurs at many but not all sites where groundwater is contaminated with chloroethenes. Metabolism of VC and ethene by strains AJ and TD is initiated by an alkene monooxygenase. Their yields during growth on VC (0.15-0.20 mg total suspended solids per mg VC) are similar to the yields reported for other isolates i.e., Mycobacterium sp., Nocardioides sp., and Pseudomonas sp.
Date: June 14, 2004
Partner: UNT Libraries Government Documents Department

Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long-Term Plume Containment

Description: Natural attenuation of TCE under aerobic conditions at the INEEL Test Area North site was demonstrated largely on the basis of preferential loss of TCE relative to conservative solutes (PCE and H-3) along groundwater flow paths. First order degradation half-lives were calculated from the rate of preferential TCE loss. We are utilizing the same approach at other DOE sites that have aerobic TCE plumes to determine if aerobic natural attenuation of TCE is rapid enough at these sites to be environmentally significant, i.e. if natural attenuation can reduce concentrations to acceptable levels before groundwater reaches potential receptors. The first step in this process was to identify TCE plumes at DOE sites that have the appropriate site conditions and data needed to perform this analysis. The site conditions include the presence of TCE in groundwater at appreciable concentrations in an aerobic aquifer, a co-mingled contaminant that can be used as a conservative tracer (e.g. PCE, H-3, Tc-99), a flow path that represents at least a decade of travel time, and several monitoring wells located along this flow path. Candidate sites were identified through interviews with knowledgeable individuals in the DOE system and by screening the U.S. Dept. of Energy Groundwater Database using the keywords ''TCE'' and ''groundwater''. The initial screening yielded 25 plumes for consideration. These sites had anywhere from one to 37 individual plumes containing TCE. Of the 25 sites, 13 sites were further evaluated because they met the screening criteria or were promising. After contacting DOE personnel from the respective sites, they were divided into three groups: (1) sites that meet all the project criteria, (2) sites that could potentially be used for the project, and (3) DOE sites that did not meet the criteria. The five sites with plumes that met the criteria were: Brookhaven National Laboratory, Lawrence ...
Date: June 1, 2003
Creator: Sorenson, Kent S. Jr.
Partner: UNT Libraries Government Documents Department


Description: The objective of this NETL sponsored bench-scale study was to demonstrate the efficacy of enhanced anaerobic reductive precipitation (EARP) technology for precipitating uranium using samples from contaminated groundwater at the Fernald Closure Project (FCP) in Cincinnati, Ohio. EARP enhances the natural biological reactions in the groundwater through addition of food grade substrates (typically molasses) to drive the oxidative-reductive potential of the groundwater to a lower, more reduced state, thereby precipitating uranium from solution. In order for this in-situ technology to be successful in the long term, the precipitated uranium must not be re-dissolved at an unacceptable rate once groundwater geochemical conditions return to their pretreatment, aerobic state. The approach for this study is based on the premise that redissolution of precipitated uranium will be slowed by several mechanisms including the presence of iron sulfide precipitates and coatings, and sorption onto fresh iron oxides. A bench-scale study of the technology was performed using columns packed with site soil and subjected to a continuous flow of uranium-contaminated site groundwater (476 {micro}g/L). The ''treated'' column received a steady stream of dilute food grade molasses injected into the contaminated influent. Upon attainment of a consistently reducing environment and demonstrated removal of uranium, an iron sulfate amendment was added along with the molasses in the influent solution. After a month long period of iron addition, the treatments were halted, and uncontaminated, aerobic, unamended water was introduced to the treated column to assess rebound of uranium concentrations. In the first two months of treatment, the uranium concentration in the treated column decreased to the clean-up level (30 {micro}g/L) or below, and remained there for the remainder of the treatment period. A brief period of resolubilization of uranium was observed as the treated column returned to aerobic conditions, but the concentration later returned to below the clean-up ...
Date: August 1, 2003
Creator: Lutes, Christopher C.; Angela Frizzell, PG; Thornton, Todd A. & Harrington, James M.
Partner: UNT Libraries Government Documents Department

Novel Imaging Techniques, Integrated with Mineralogical, Geochemical and Microbiological Characterization to Determine the Biogeochemical Controls....

Description: Tc(VII) will be reduced and precipitated in FRC sediments under anaerobic conditions in batch experiments (progressive microcosms). The complementary microcosm experiments using low pH/nigh nitrate sediments from 3 (near FW 009) are imminent, with the sediment cores already shipped to Manchester. HYPOTHESIS 2. Tc(VII) reduction and precipitation can be visualized in discrete biogeochemical zones in sediment columns using 99mTc and a gamma-camera. Preliminary experiments testing the use of 99mTc as a radiotracer to address hypotheses 2 and 3 have suggested that the 99mTc associates with Fe(II)-bearing sediments in microcosms and stratified columns containing FRC sediments. Initial proof of concept microcosms containing Fe(II)-bearing, microbially-reduced FRC sediments were spiked with 99mTc and imaged using a gamma-camera. In comparison with oxic controls, 99mTc was significantly partitioned in the solid phase in Fe(III)-reducing sediments in batch experiments. Column experiments using FRC background area soil with stratified biogeochemical zones after stimulation of anaerobic processes through nutrient supplementation, suggested that 99mTc transport was retarded through areas of Fe(III) reduction. HYPOTHESIS 3. Sediment-bound reduced 99mTc can be solubilized by perturbations including oxidation coupled to biological nitrate reduction, and mobilization visualized in real-time using a gamma-camera. Significant progress has been made focusing on the impact of nitrate on the biogeochemical behavior of technetium. Additions of 100 mM nitrate to FRC sediment microcosms, which could potentially compete for electrons during metal reduction, inhibited the reduction of both Fe(III) and Tc(VII) completely. Experiments have also addressed the impact of high nitrate concentrations on Fe(II) and Tc(IV) in pre-reduced sediments, showing no significant resolubilization of Tc with the addition of 25 mM nitrate. A parallel set of experiments addressing the impact of aerobic conditions on the stability/solubility of Fe(II) and Tc(IV), found 80 % resolubilization of the Tc. Column experiments exploring this behavior are being planned. HYPOTHESIS 4 The mobility of ...
Date: June 1, 2005
Creator: Lloyd, Jonathan R.
Partner: UNT Libraries Government Documents Department


Description: This report documents the laboratory testing and analyses as directed under the test plan, LAB-PLN-11-00010, Evaluation of Technetium Ion Exchange Material against Hanford Double Shell Tank Supernate Simulate with Pertechnetate. Technetium (Tc-99) is a major fission product from nuclear reactors, and because it has few applications outside of scientific research, most of the technetium will ultimately be disposed of as nuclear waste. The radioactive decay of Tc-99 to ruthenium 99 (Ru-99) produces a low energy {beta}{sup -} particle (0.1 MeV max). However, due to its fairly long half-life (t{sub 1/2} = 2.13E05 years), Tc-99 is a major source of radiation in low-level waste (UCRL-JRNL-212334, Current Status of the Thermodynamic Data for Technetium and its Compounds and Aqueous Species). Technetium forms the soluble oxy anion, TcO{sub 4}{sup -} under aerobic conditions. This anion is very mobile in groundwater and poses a health risk (ANL, Radiological and Chemical Fact Sheets to Support Health Risk Analyses for Contaminated Areas). It has been demonstrated that Purolite{reg_sign} A530E is highly effective in removing TcO{sub 4}{sup -} from a water matrix (RPP-RPT-23199, The Removal of Technetium-99 from the Effluent Treatment Facility Basin 44 Waste Using Purolite A-530E, Reillex HPQ, and Sybron IONAC SR-7 Ion Exchange Resins). Purolite{reg_sign} A530E is the commercial product of the Oak Ridge National Laboratory's Biquat{trademark} resin (Gu, B. et. ai, Development of Novel Bifunctional Anion-Exchange Resins with Improved Selectivity for Pertechnetate Sorption from Contaminated Groundwater). Further work has demonstrated that technetium-loaded A530E achieves a leachability index in Cast Stone of 12.5 (ANSI/ASN-16.1-2003, Measurement of the Leachability of Solidified Low-Level Radioactive Wastes by a Short-term Test Procedure) as reported in RPP-RPT-39195, Assessment of Technetium Leachability in Cement-Stabilized Basin 43 Groundwater Brine. This effort falls under the technetium management initiative and will provide data for those who will make decisions on the handling and ...
Date: April 17, 2012
Partner: UNT Libraries Government Documents Department


Description: The authors have isolated many Cd (II) resistant bacterial strains from relatively pristine sediments collected from salt marshes in Shelter Island, New York. Detailed studies are being performed on one isolate, strain Cd-1. Strain Cd-1 is metabolically diverse, halotolerant, Gram-negative, facultative anaerobe. It can resist high amounts of Cd (II), Cr (VI), As (V), Se (IV), Co (II), Pb (II), or Zn (II) under defined anaerobic conditions. With pyruvate as the energy source, Cd-1 can grow well at examined Cd (II) concentrations ranging up to 15 mM. It can resist Cd (II) with or without marine level NaCl concentration, under acidic or neutral conditions. It can resist Cd (II) under aerobic conditions as well. These features are novel for a heavy metal resistant bacterium.
Date: June 20, 1999
Partner: UNT Libraries Government Documents Department

Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long-Term Plume Containment - Task 4: Modeling - Final Report

Description: Trichloroethene (TCE), a common groundwater contaminant, can be degraded under certain conditions by microorganisms that occur naturally in the subsurface. TCE can be degraded under anaerobic conditions to less chlorinated compounds and ultimately into the non-chlorinated, non-hazardous end product, ethene, via anaerobic reductive dechlorination (ARD). ARD is widely recognized as a TCE degradation mechanism, and occurs in active groundwater remediation and can occur during monitored natural attenuation (MNA). MNA relies on natural processes, such as dispersion and degradation, to reduce contaminant concentrations to acceptable levels without active human intervention other than monitoring. TCE can also be biodegraded under aerobic conditions via cometabolism, in which microbial enzymes produced for other purposes fortuitously also react with TCE. In cometabolism, TCE is oxidized directly to non-hazardous products. Cometabolism as a TCE-degrading process under aerobic conditions is less well known than ARD. Natural attenuation is often discounted as a TCE remedial alternative in aerobic conditions based on the paradigm that TCE is biodegradable only under anaerobic conditions. In contrast to this paradigm, TCE was shown to degrade relative to conservative co-contaminants at an environmentally significant rate in a large (approximately 3 km long) TCE plume in aerobic groundwater at the Idaho National Laboratory (INL), and the degradation mechanism was shown to be cometabolism. MNA was selected as the remedy for most of this plume, resulting in a considerable cost savings relative to conventional remedial methods. To determine if cometabolism might be a viable remedy at other sites with TCE-contaminated aerobic groundwater, TCE plumes at Department of Energy (DOE) facilities were screened to evaluate whether TCE commonly degrades in aerobic groundwater, and if degradation rates are fast enough that natural attenuation could be a viable remedy. One hundred and twenty seven plumes at 24 DOE facilities were screened, and 14 plumes were selected for detailed ...
Date: October 31, 2005
Creator: Starr, Robert C.
Partner: UNT Libraries Government Documents Department

Evaluation of wastewater treatment requirements for thermochemical biomass liquefaction

Description: The broad range of processing conditions involved in direct biomass liquefaction lead to a variety of product properties. The aqueous byproduct streams have received limited analyses because priority has been placed on analysis of the complex organic liquid product. The range of organic contaminants carried in the aqueous byproducts directly correlates with the quantity and quality of contaminants in the liquid oil product. The data in the literature gives a general indication of the types and amounts of components expected in biomass liquefaction wastewater; however, the data is insufficient to prepare a general model that predicts the wastewater composition from any given liquefaction process. Such a model would be useful in predicting the amount of water that would be soluble in a given oil and the level of dissolved water at which a second aqueous-rich phase would separate from the oil. Both biological and thermochemical processes have proposed for wastewater treatment, but no treatment process has been tested. Aerobic and anaerobic biological systems as well as oxidative and catalytic reforming thermochemical systems should be considered.
Date: May 1, 1992
Creator: Elliott, D.C.
Partner: UNT Libraries Government Documents Department

Growth response of microorganisms to different molecular fractions of lignite

Description: Our research is primarily concerned with isolating and characterizing microbes which are able to dissimilate coal and convert it to other useful chemicals. This quarter, general growth responses of microorganisms cultivated in the presence of different molecular weight fractions of lignite coal were examined. Aerobic and anaerobic environmental samples from a variety of ecological niches were used as inocula. Growth of the microorganisms in these samples on the following types of media was tested: COAL medium, containing alkali-solubilized whole coal; THFI medium, containing the alkali-solubilized, tetrahydrofuran-insoluble, macromolecular portion of whole coal; THFS medium, containing the THF-soluble, low molecular weight portion of whole coal; and CON medium, void of any coal constituent. Overall results indicated that the presence of the THF-soluble, low molecular weight coal fraction enhanced the growth yield and the variety of aerobic microorganisms compared to the other coal fractions or the control medium. Conversely, anaerobic microbes grew best on media which contained the macromolecular fraction. 12 refs., 5 tabs.
Date: January 1, 1990
Creator: Polman, J.K.; Breckenridge, C.R.; Dugan, P.R. & Quigley, D.R.
Partner: UNT Libraries Government Documents Department