Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 68 for “"sulfate reduction"”.
-
Physiology of multiple sulfur isotope fractionation during microbial sulfate reduction
Microbial sulfate reduction (MSR) utilizes sulfate as an electron acceptor and produces sulfide that is depleted in heavy isotopes of sulfur relative to starting sulfate. The fractionation of S-isotopes is commonly used to trace the biogeochemical cycling of sulfur in nature, but a mechanistic …
-
Bioremediation of Effluent Water in a Coal Ash Disposal Area: Optimizing Microbial Sulfate Reduction
… This study focuses on the issue of elevated sulfate concentrations at the Martin Lake Steam Electric Station (MLSES) A-I Disposal Area in Panola County, Texas, where CCR are disposed of in a permanent landfill. Currently, this site is exceeding its regulatory limit of sulfate concentrations …
-
Quantifying the expression of dissimilatory sulfite reductase as a metric for sulfate reduction rates
… reductase (dsr mRNA), a critical enzyme in the sulfate reduction pathway, can serve as an indicator of the rate of sulfate reduction in natural systems. We grew Desulfovibrio vulgaris in fed-batch reactors under electron-donor limiting conditions. To simulate conditions characteristic of …
-
Sulfate reduction and iron-manganese cycling in intertidal surface sediments of the southern North Sea
Zielsetzung der vorliegenden Dissertation ist die Erfassung der Dynamik der Mangan-, Eisen- und Schwefel-Kreisläufe in unterschiedlichen intertidalen Sedimenten. Saisonale biogeochemische Untersuchungen in Sand-, Misch-, und Schlickwatt-Sedimenten der Nordseeinsel Spiekeroog geben Aufschluss über …
-
A revised monod-type rate law predicting variable sulfur isotope fractionation factors as a function of microbial sulfate reduction rate
Microbial sulfate reduction is associated with characteristic sulfur isotope partitioning, which can serve as a proxy for the rate of this reactivity in a wide variety of reducing environments. We demonstrate a new model for this functional relationship through the use of a modified Monod-type rate …
-
The effect of carbon addition, pH and Fe concentration of microbial sulfate reduction and the subsequent precipitation of Fe and Mn from acid mine drainage in wetland mesocosms
… total Fe, 3 mg/L total Mn and 450 mg/L dissolved sulfate. An 18 month field study of water quality improvement and sulfate-reducing bacterial (SRB) populations revealed that the wetland was effectively treating the AMD. Iron and Mn both met compliance standards set by the EPA requiring an instream …
-
The role of sulfur in salt marsh metabolism
The rate of sulfate reduction in stands of dwarf Spartina alterniflora in the Great Sippewissett Salt Marsh is approximately 75 moles S04 m2 year-1. This is the highest rate reported for any natural ecosystem. Sulfate reduction is the most important form of respiration in the marsh and results in …
-
Enhanced Microbial Sulfate Removal Through a Novel Electrode-Integrated Bioreactor
In northeast Minnesota, elevated levels of sulfate in freshwater systems is a topic of great interest, due to potential adverse impacts to wild rice ecosystems. Sulfate may contribute to methylmercury production and eutrophication in certain conditions. Increased interest has emerged for developing …
-
Expression of dsr messenger RNA by sulfate reducing bacteria with varying substrate and temperature
… the possibility of estimating the activity of sulfate reducing bacteria by measuring the number of messenger RNA (mRNA) transcripts of dsr, a critical gene in the sulfate reduction pathway, in a cell. Because conditions in aquifers can be quite different from those maintained in laboratory …
-
Aufwuchs communities of lotic systems: nontaxonomic structure and function
… function (primary productivity and assimilatory sulfate reduction). In eleven experiments, individual streams were treated with potential"enrichments" of sucrose, dextrose, ammonium nitrate, potassium dihydrogen phosphate, and toxicants including copper sulfate, potassium dichromate and chlorine, …
-
SEASONAL BIOCHEMISTRY IN THE SEDIMENTS OF THE GREAT BAY ESTUARINE COMPLEX, NEW HAMPSHIRE
… radiometrically as glucose turnover and sulfate reduction rates. Analyses of pore water concentrations of sulfate, chloride, iron and organic carbon, sedimentary concentrations of acid-volatile sulfides, and the abundance of sulfate-reducing bacteria were also made.</p><p>Average annual …
-
Organic matter remineralization in the sediment of two acid mine drainage lakes
… depth profiles of ferrous iron (Fe2+), sulfate (SO42-), manganese (Mn2+), and dissolved inorganic carbon (DIC) and to model rates. Results showed Red Lake had significantly higher Fe2+, Mn2+, and SO42- concentrations in the pore water than Green Lake. Iron and sulfate reduction occurred …
-
The formation of carbonate minerals in laboratory and environmental settings
Microbial sulfate reduction, couple to organic matter oxidation or methane oxidation, is one of the key processes driving the formation of sedimentary carbonate minerals. While some work has been done exploring the formation of carbonate minerals via microbial sulfate reduction, less attention has …
-
Numerical modeling of chemical recovery from black liquor char
… a multiphase CFD code MFIX. Rate equations for sulfate reduction by carbon, gasification of carbon by CO2 and H2O, and, COS and H2S formation, are incorporated into MFIX, to simulate the chemical kinetics occurring in the char burning stage. Oxidation of carbon and Na 2S by O2 are also …
-
Extension and verification of the PWM_SA model to incorporate SANI-specific bioprocesses using experimental data from the Hong Kong SANI saline sewage treatment pilot plant.
… adapting the PWM_SA model to incorporate sulfate reduction, autotrophic denitrification, and nitrification processes characteristic of the SANI system, focusing on achieving accurate mass balance across key chemical species and overall internal consistency. Specifically, the model …
-
Using 34-S as a Tracer of Dissolved Sulfur Species from Springs to Cave Sulfate Deposits in the Cerna Valley, Romania
… of dissolved sulfide gas (H2S) and dissolved sulfate (SO4²-).These dissolved species indicate the progression of sulfate reduction in the aquifer. Water samples were collected in polyethylene syringes to prevent oxidation of sulfide. Then, sulfide and sulfate were quantitatively reacted for …
-
A preliminary assessment for the use of metabolic inhibitors to evaluate the biodegradation potential of soil
… sulfonic acid (BESA), which inhibit sulfate reduction and methanogenesis, respectively. Denitrification was suppressed by the absence Of sodium nitrate (NaNO3) in the microcosm dilution water. Both Newport News and Blacksburg soils were found to be dominated by denitrfying bacteria. …
-
Biological and Membrane Treatment Applications for the Reduction of Specific Conductivity and Total Dissolved Solids in Coal Mine Waters
… on SC for all mining operation outfalls. Sulfate typically has the greatest dissolved ion presence in coal mine waters. In literature examining the treatment of mine waters, SC and TDS analysis is typically not reported. The technologies examined in this study were nanofiltration membrane …
-
Effects of Capping on Biodegradation of Organic Contaminants in Sediments
… of 14C–phenanthrene was strongly linked to sulfate reduction, which was the more energetic process than any other anaerobic condition in Anacostia sediments. Sulfate is a more promising terminal electron acceptor for intrinsic degradation in Anacostia River and other PAH contaminated sites. …
-
Geochemical Controls on Mercury Methylation in Backwaters of a Gulf Coastal Plain River System, Implications for Water Column Processes
… of 74.0-142.7 micrograms/liter indicate sulfate reduction was occurring in the bottom water or at the sediment-water interface, yet filtered and particulate methyl mercury concentrations were not significantly correlated to sulfide concentrations. The occurrence of sulfides in the …
Page 1 of 4