Download or read book Characterization of an Anaerobic Microbial Community in a TCE Contaminated Aquifer and the Degradation of TCE by Pantoea Agglomerans written by Evan C. Griffiths and published by . This book was released on 2001 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bacterial community composition TCE degradation isotopic fractionation and toxicity of a TCE contaminated aquifer written by Jillian Brown and published by . This book was released on 2009 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comparative Evaluation of Biostimulation Approaches for Enhancing In situ TCE Degradation in Contaminated Aquifers written by Bridget Nolan Moran and published by . This book was released on 1996 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book American Doctoral Dissertations written by and published by . This book was released on 2001 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Microbial Communities in TCE Contaminated Seep Zone Sediments written by and published by . This book was released on 2005 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hundreds of sites across the United States contain trichloroethene (TCE) contamination, including the Department of Energy's Savannah River Site (SRS) in Aiken, South Carolina. Previous studies have indicated that microorganisms are capable of efficiently degrading TCE to nonhazardous end products. In this project, molecular and growth based methods were used for microbial characterization of a TCE impacted seepzone where TCE degradation is naturally occurring. The results from this work provide clear evidence that the SRB may play a significant role in TCE degradation along the Twin Lakes seepline.

Download or read book Anaerobic Degradation of 1 1 2 2 tetrachloroethane and Association with Microbial Communities in a Freshwater Tidal Wetland Aberdeen Proving Ground Maryland written by Michelle M. Lorah and published by . This book was released on 2003 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Assessment of the Microbial Communities Derived from Two Tetrachloroethene PCE contaminated Aquifers written by Rebekah Ruth Helton and published by . This book was released on 2000 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Anaerobic Reductive Dechlorination of TCE and TCFE in TCE Contaminated Sediments written by Jae-Hyuk Lee and published by . This book was released on 2006 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research focused on the enhanced reductive dechlorination of trichloroethene (TCE) and its surrogate, trichlorofluoroethene (TCFE), using two bioremediation methods in anaerobic conditions. Two anaerobic bioremediation studies were conducted to investigate the effects of microbial communities in the presence of different electron acceptors and donors during anaerobic reductive dechlorination of TCE and TCFE. The first study was conducted in the groundwater microcosm bottles, filled with groundwater and sediments collected from Richmond site, CA. Parallel reductive dechlorination of TCE and TCFE was evaluated in the presence of fumarate and its product, succinate, while active reduction of high background concentrations of sulfate (2.5 mM) occurred. Because sulfate was assumed as a favorable electron acceptor during reductive dechlorination of chlorinated aliphatic hydrocarbons (CAHs), all microcosms receiving TCE and TCFE with substrates showed enhanced reductive dechlorination activity and even no substrate addition microcosms generated biotransformation products. From the electron mass balance calculations, more than 87.5% of electrons went to sulfate reduction and less than 10% of available electrons involved in dechlorination after sulfate reductions. After amending varying concentrations of sulfate (0 2.5 mM), no inhibition was found between reductive dechlorination of TCE and sulfate reduction. The result indicated that reductive dechlorination could be directly competed with sulfate reduction for available electrons. The second study investigated the effectiveness of in situ push-pull tests to evaluate bioaugmentation in physical aquifer models (PAMs) using dehalogenating strains to reductively dechlorinate TCE to ethene and TCFE to FE in the TCE contaminated sediments. Complete reduction of TCE to ethene occurred in less than 14 days with repeated additions of TCE (13.0 to 46.0 mg/L) and TCFE (15.0 mg/L) was completely transformed to FE in under 24 days. Increased rate and extent of dechlorination in the bioaugmented PAM compared to the nonaugmented control PAM indicated successful transport of the bioaugmented culture through the PAM. Similar transformation rates and time course of TCE and TCFE also indicated that TCFE was a bioprobe for reductive dechlorination of TCE. TCE and TCFE were transformed to cisdichloroethene (c-DCE) and cis-dichlorofluoroethene (c-DCFE) respectively at two of the three sampling ports after 50 days of incubation in the nonaugmented PAM indicating reductive dechlorination activity of indigenous microorganisms. The results showed that it is possible to increase the rate and extent of reductive dechlorination of TCE and TCFE by bioaugmentation and that push-pull tests are effective tools for detecting and quantifying these processes in situ. The third study focused on numerical modeling of the second study. The objectives of this study were (1) to evaluate a simplified method for estimating retardation factors for injected solutes and bioaugmented microorganisms using "pushpull" test injection phase breakthrough curves, (2) to identify whether bioaugmented microorganisms have kept the same transformation capacity of Evanite culture using Michaelis-Menten kinetics by the values provided by Yu et al. (2005) and to verify in situ rates of TCFE reductive dechlorination rates of push-pull tests by numerical modeling, and (3) to investigate a reasonable answer for the nonuniform recovery of ethene and FE during the activity test and the push-pull test. The bioaugmented microorganisms were effectively transported through Hanford sediment. The estimated retardation factor was 1.33. A numerical simulation predicted cell transport in the PAM as far as port 5. This was qualitatively confirmed by cell counts obtained during bioaugmentation but, cells were distributed nonuniformly. The transport test indicated that TCE and TCFE transport was relatively retarded compared to coinjected bromide tracer (retardation factors ranged from 1.33-1.62 for TCE and from 1.44-1.70 for TCFE). The modeling simulation of Michaelis-Menten kinetics for the activity test was well matched for reductive dechlorination rates for TCE and less dechlorinated ethenes using the previous published values of kmax and Ks of chlorinated ethenes by Yu et al. (2005); the model match indicated that the bioaugmented microorganisms kept the same transformation capacity as the original source, Evanite culture (Yu et al., 2005) over 4 months in the PAM. A numerical simulation resulted in the simple first order FE production rate of 1 day' using STOMP code (2002) and the value of FE production rate was in the range of the transformation rates of TCFE during the activity test. The bioaugmented PAM has caused slow loss of injected CAHs during the activity test and the push-pull test.

Download or read book Anaerobic Dechlorination of TCE by Microorganisms Enriched from a Contaminated Groundwater Site written by Robert Brent Nielsen and published by . This book was released on 1999 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Anaerobic Biotransformation of Contaminants in the Subsurface written by Joseph M. Suflita and published by . This book was released on 1991 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Impacts of Contamination and Remediation on Microbial Communities in Anaerobic Groundwater written by Michele D. Zwolinski and published by . This book was released on 2002 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applied and Environmental Microbiology written by and published by . This book was released on 1996 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Microbial Ecology of Aromatic Compound Degradation in a Coal Tar Waste Contaminated Aquifer written by Jane Miyuki Yagi and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial ecology links community structure, phenotypic potential, community function and interactions of microorganisms within communities and with their environments. Native microbial populations are responsible for biodegradation of naphthalene and other organic pollutants in a shallow coal tar waste-contaminated aquifer in South Glens Falls, NY. Though many details of the biochemistry and genetics of bacterial naphthalene degradation are known from studies in pure culture, molecular methods of analysis applied in situ can significantly advance understanding of microbial degradation processes in an ecological context. PCR-based molecular characterization of 16S and 18S rRNA genes was used to significantly extend previous work characterizing the microbial communities in site groundwater, and to establish the temporally dynamic nature of native microbial communities. Long term natural attenuation of pollutants was documented, and the presence of members of a potentially intricate microbial food web was linked to organic contamination in the subsurface waters. A broadrange PCR assay was used to uncover a diverse suite of Rieske dioxygenase genes, including 32 previously uncharacterized clone groups, in 2 contaminated wells within the aquifer. A quantitative competitive PCR assay detecting nah and nag genes, encoding naphthalene dioxygenase, showed that these biochemically divergent pathways (associated with aerobic naphthalene con- version to either catechol or gentisate, via salicylate) were prevalent at the site. RT-PCR results showed that both genes were transcribed in situ, at micromolar concentrations of ambient naphthalene, in proportions corresponding with structural gene abundance. Aerobic but not anaerobic naphthalene metabolism was observed in site water incubation experiments. However, metabolites of anaerobic naphthalene metabolism and expressed anaerobic degradation pathway mRNA transcripts (bssA) were detected in situ showing that anerobic metabolism of contaminants occurred on site. Cytochrome c nitrite reductase and ammonia monooxygenase gene expression in situ provided evidence of a complete nitrogen cycle via dissimilatory nitrate reduction to ammonia (DNRA) and nitrification carried out by native microbial communities. These data suggest that conditions in the contaminated aquifer had progressed from heterotrophic (carbon-oxidizing) to accumulation of reduced metabolic end products (ammonia, sulfide, methane) supporting lithotrophic and otherwise absent microbial populations. Genome analysis of the aromatic hydrocarbon-degrading, facultatively chemolithotrophic, contaminated sediment-dwelling [beta]-proteobacterium, Polaromonas naphthalenivorans strain CJ2, revealed a mosaic chromosome and 8 extrachromosomal elements. Comparisons with the closest sequenced relative, Polaromonas JS666, and related [beta]-proteobacteria revealed both substantial homology and fluidity of genetic content. The genomic context and lateral transfer origins of the chromosomally encoded nag-like naphthalene catabolic operon were analyzed. Mobile genetic elements, signal transduction pathways, central and peripheral metabolic pathways, energy metabolism, transport systems, inorganic nutrient scavenging mechanisms, carbon and energy storage functions, and oxidative stress tolerance mechanisms were investigated in detail.

Download or read book Anaerobic Degradation of Chlorinated Hydrocarbons in Groundwater Aquifers Or Chlorinated Hydrocarbon Degradation written by R. Brent Nielsen and published by . This book was released on 1997 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Anaerobic Methyl Tert butyl Ether MTBE degrading Communities written by Tong Liu and published by . This book was released on 2015 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: The wide use of methyl tert-butyl ether (MTBE), a synthetic fuel oxygenate, have caused extensive contamination in groundwater in past two decades and resulted in taste, odor, and potential toxicity problems in drinking water. MTBE contaminated groundwater aquifer is often depleted of oxygen and microorganisms can anaerobically degraded MTBE under a verity of redox conditions. It has been demonstrated that MTBE can be degraded anaerobically which makes in situ bioremediation of contaminated aquifers a potential solution to address this problem. Assessment and enhancement of MTBE bioremediation requires knowledge of the microorganisms that responsible for biodegradation process. However, it is challenge to isolate anaerobic MTBE-degrading microorganisms or to characterize the microbial communities. The aim of this study was to identify the organisms that mediate anaerobic biodegradation of MTBE in methanogenic or sulfidogenic cultures enriched from estuarine sediments. Stable isotope probing (SIP) combined with terminal restriction fragment length polymorphism (T-RFLP) analysis showed that Ruminococcaceae species were active in methanogenic MTBE-degrading community. T-RFLP coupled with clone library analysis of bacterial 16S rRNA genes from sulfidogenic enrichment cultures showed Deltaproterobacteria were highly enriched than the other phylogenetically diverse populations. We also investigated MTBE-degrading communities by single cell using Raman Spectroscopy and SIP. The results confirmed the MTBE degraders are not abundant in the communities. This study provides crucial information for understanding the mechanisms of anaerobic degradation of MTBE as well as for assessment of the in situ bioremediation at contaminated field sites as the microbial/molecular tools.

Download or read book Bioaugmentation with Burkholderia Cepacia PR1301 for in Situ Bioremediation of Trichloroethylene Contaminated Water written by and published by . This book was released on 1998 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Microbial Communities in Pristine and Tetrachloroethylene contaminated Aquifer Sediment written by Merry Shannon Riley-Buckley and published by . This book was released on 2001 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: