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Reductive Dechlorination Of Tetrachloroethene In Polluted Aquifer Microcosms And Isolation Of Anaerobic Bacteria From A Tetrachloroethene Dechlorinating Enrichment
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Book Synopsis Reductive Dechlorination of Tetrachloroethene in Polluted Aquifer Microcosms and Isolation of Anaerobic Bacteria from a Tetrachloroethene-dechlorinating Enrichment by : Christopher D. Carlson
Download or read book Reductive Dechlorination of Tetrachloroethene in Polluted Aquifer Microcosms and Isolation of Anaerobic Bacteria from a Tetrachloroethene-dechlorinating Enrichment written by Christopher D. Carlson and published by . This book was released on 1997 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis לקט מקורות לקורס: סוגיות הלכתיות בספר דברים by :
Download or read book לקט מקורות לקורס: סוגיות הלכתיות בספר דברים written by and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Exploring Anaerobic Reductive Dechlorination at Low PH Environments by : Yi Yang
Download or read book Exploring Anaerobic Reductive Dechlorination at Low PH Environments written by Yi Yang and published by . This book was released on 2012 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chlorinated aliphatic hydrocarbons (CAHs), such as tetrachloroethene (PCE) and trichloroethene (TCE), are ubiquitously pollutants in aquifer sediments and groundwater due to their heavy usage in industry and inappropriate disposal in the last century. Among about 1300 NPL (National Priorities List) sites, PCE and TCE are the two most frequently detected hazardous contaminants. Engineered bioremediation, including biostimulation and bioaugmentation, is a promising technology to clean those PCE and/or TCE contaminated sites. However, in many contaminated groundwater systems and hazardous waste sites, pH can be lower than 5 to 6. And release of HCl (strong acid) from anaerobic reductive dechlorination may lower the pH of groundwater. Besides, another main source of acidity comes from the fermentation of additive electron donors such as alcohols, organic acids and etc. Decreasing pH has been proved to be detrimental to the microbes that dechlorinated PCE or TCE. We intended to enrich and isolate microorganisms, which can perform anaerobic reductive dechlorination at low pH environments, by establishing microcosms, which will be beneficial to in situ bioremediation. We also screened some existing cultures for dechlorinating activity at low pH and determined the pH tolerance of consortium BDI, which had been successfully, applied for in situ bioremediation. Besides, this study investigated and explored the effects of solids on BDI consortium under low pH conditions. Generally, various dechlorinating pure cultures and consortium BDI show highest dechlorination rates and extent at circumneutral pH. Only Sulfurospirillum multivorans among tested cultures dechlorinated PCE to cDCE at pH 5.5. The screening efforts suggest that microbes capable of dechlorination below pH 5.5 are not common. It was observed that solids play an important role for enhancing microbial activities under low pH conditions. And BDI consortium can recover from up to 8 weeks exposure to low pH conditions, although the VC-to-ethene dechlorination step was affected.
Book Synopsis Bioaugmentation for Groundwater Remediation by : Hans F. Stroo
Download or read book Bioaugmentation for Groundwater Remediation written by Hans F. Stroo and published by Springer Science & Business Media. This book was released on 2012-10-02 with total page 421 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides a review of the past 10 to 15 years of intensive research, development and demonstrations that have been on the forefront of developing bioaugmentation into a viable remedial technology. This volume provides both a primer on the basic microbial processes involved in bioaugmentation, as well as a thorough summary of the methodology for implementing the technology. This reference volume will serve as a valuable resource for environmental remediation professionals who seek to understand, evaluate, and implement bioaugmentation.
Book Synopsis Anaerobic Reductive Dechlorination of TCE and TCFE in TCE Contaminated Sediments by : Jae-Hyuk Lee
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.
Book Synopsis Reductive Dechlorination of High Concenrations of Tetrachloroethylene by Anaerobic Enrichment Culture by : Tao Wang
Download or read book Reductive Dechlorination of High Concenrations of Tetrachloroethylene by Anaerobic Enrichment Culture written by Tao Wang and published by . This book was released on 1997 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Anaerobic Dechlorination of TCE by Microorganisms Enriched from a Contaminated Groundwater Site by : Robert Brent Nielsen
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:
Book Synopsis Organohalide-Respiring Bacteria by : Lorenz Adrian
Download or read book Organohalide-Respiring Bacteria written by Lorenz Adrian and published by Springer. This book was released on 2016-08-03 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the current state of knowledge concerning bacteria that use halogenated organic compounds as respiratory electron acceptors. The discovery of organohalide-respiring bacteria has expanded the range of electron acceptors used for energy conservation, and serves as a prime example of how scientific discoveries are enabling innovative engineering solutions that have transformed remediation practice. Individual chapters provide in-depth background information on the discovery, isolation, phylogeny, biochemistry, genomic features, and ecology of individual organohalide-respiring genera, including Dehalococcoides, Dehalogenimonas, Dehalobacter, Desulfitobacterium and Sulfurospirillum, as well as organohalide-respiring members of the Deltaproteobacteria. The book introduces readers to the fascinating biology of organohalide-respiring bacteria, offering a valuable resource for students, engineers and practitioners alike.
Book Synopsis The Reductive Dechlorination of Tetrachloroethylene, Trichloroethylene, and Carbon Tetrachloride Mixtures by Anaerobic Bacteria by : Rebecca Davis
Download or read book The Reductive Dechlorination of Tetrachloroethylene, Trichloroethylene, and Carbon Tetrachloride Mixtures by Anaerobic Bacteria written by Rebecca Davis and published by . This book was released on 1999 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Isolation and Ecology of Bacterial Populations Involved in Reductive Dechlorination of Chlorinated Solvents by : Youlboong Sung
Download or read book Isolation and Ecology of Bacterial Populations Involved in Reductive Dechlorination of Chlorinated Solvents written by Youlboong Sung and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The findings of this study demonstrate that Dehalococcoides species are intimately involved in complete reductive detoxification of chlorinated ethenes and are widely distributed in anoxic sediments and aquifers, including non-contaminated (pristine) environments. Careful examination of enrichment culture dechlorination kinetics, 16S rRNA gene based analyses, and reductive dehalogenase gene targeted PCR approaches revealed that complete reductive dechlorination is carried out by multiple dechlorinators. Two new dechlorinating species were isolated from contaminated and non-contaminated site materials. The first new isolate, designated strain SZ, was isolated from PCE-to-ethene dechlorinating microcosms established with creek sediment. 16S rRNA gene sequence of the strain SZ indicates that the new isolate is affiliated with the genus Geobacter most closely related to G. thiogenes. Strain SZ is capable of stepwise dechlorination of PCE to cis-DCE, while the closest relatives were not able to dechlorinate PCE or TCE. Dechlorination of PCE or TCE by strain SZ was supported by acetate, hydrogen or pyruvate as electron donor. Chloroethene-dechlorinating populations have been shown to have distinct electron donor requirements. However, none of previously described chlorinated ethene degrading population can use both, acetate and hydrogen, as electron donors. PCE dechlorination by strain SZ uses both acetate and hydrogen as electron donors suggesting that the ability to versatile electron donor utilization may increase the efficiency of bioremediation approaches. Importantly, strain SZ reduced two environmental priority pollutants, PCE and U(VI) concomitantly and detected from both bio-stimulated chloroethene and uranium contaminated sites, strongly suggesting that strain SZ play a important roles in in-situ bioremediation of chloroethene and U(VI) contaminated sites. The second, a new Dehalococcoides species designated strain GT, was isolated from contaminated site materials. Strain GT uses trichloroethene (TCE), cis-DCE, 1,1-dichloroethene (1,1-DCE), and the human carcinogen vinyl chloride (VC) as growth supporting electron acceptors producing products ethene and inorganic chloride. The new isolate shares common traits of Dehalococcoides such as ampicillin resistance, strict hydrogen-dependent metabolism, and a low hydrogen consumption threshold concentration. Culture-dependent and independent, 16S rRNA gene and reductive dehalogenase gene targeted PCR approaches suggested culture purity.
Book Synopsis Development and Characterization of a Rapid Dechlorinating Enrichment Stimulated from an Aquifer Contaminated with Chlorinated Ethenes and Ethanes by : Haekyung Kim
Download or read book Development and Characterization of a Rapid Dechlorinating Enrichment Stimulated from an Aquifer Contaminated with Chlorinated Ethenes and Ethanes written by Haekyung Kim and published by . This book was released on 2004 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis "Dehalococcoides Ethenogenes" Strain 195 by : Xavier Maymó-Gatell
Download or read book "Dehalococcoides Ethenogenes" Strain 195 written by Xavier Maymó-Gatell and published by . This book was released on 1997 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tetrachioroethene (PCE) is a human carcinogen, and together with trichloroethane (TCE), is widely used. Due to improper handling, they are among the most frequently found groundwater pollutants. A purified, PCE-dechlorinating enrichment culture was developed. This non-methanogenic, non-acetogenic culture could grow with H2 as the electron donor, indicating that H2/PCE serves as an electron donor/acceptor for energy conservation and growth. A novel anaerobic bacterium which dechlorinates PCE to the non-toxic product ethene (ETH), "Dehalococcoides ethenogenes' strain 195, was isolated from this enrichment. This is the first pure culture capable of complete PCE dechlorination. 'D. ethenogenes' strain 195 is an irregular coccus with an optimal growth temperature of 35 deg C and pH of 6.8-7.5. Phylogenetic analysis indicates that it is a eubacterium which shows no affiliation to known groups. Electron donors tested other than H2 were not utilized nor were electron donors other than TCE, cis-dichloroethene (cis-DCE), 1,1-DCE, and dichloroethane, which could be freely interchanged and were dechlorinated to ETH. This organism could not grow on vinyl chloride or trans-DCE when provided as sole electron acceptors, but both were dechlorinated cometabolically by cells previously grown on PCE. The reduction of VC to ETH was the rate-limiting reaction to the complete dechlorination of PCE. PCE, TCE, cis-DCE, and 1,1-DCE inhibited ETH formation from VC when present, but, at low concentrations, their dechlorination coexisted with ETH production. Cultures grown on cis-DCE as sole electron acceptor could not dechlorinate PCE unless PCE and cis-DCE were added together.
Book Synopsis Abiotic Reductive Dechlorination of Tetrachloroethylene and Trichloroethylene in Anaerobic Environments by :
Download or read book Abiotic Reductive Dechlorination of Tetrachloroethylene and Trichloroethylene in Anaerobic Environments written by and published by . This book was released on 2009 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tetrachloroethylene (PCE) and trichloroethylene (TCE) are among the most frequently detected ground water contaminants at industrial sites, including many DoD facilities. Due to the high cost and uneven performance of traditional remediation technologies, monitored natural attenuation is emerging as a new technology for ground water remediation of pollutants such as these. In addition, there is growing interest in active remediation technologies that employ abiotic minerals. PCE and TCE are susceptible to reductive dechlorination by microorganisms as well as reduced minerals such as iron sulfide (FeS). Unlike biological reductive dechlorination, which often results in accumulation of harmful intermediates such as cis 1,2-dichloroethylene (cis-DCE) and vinyl chloride (VC), abiotic mineral-mediated dechlorination of PCE and TCE tends to result in complete transformation to non-toxic products such as acetylene. To more accurately apply natural attenuation and other remediation technologies, a greater understanding of the geochemical factors affecting the rates of purely abiotic reductive dechlorination of PCE and TCE is needed. Additional tools are also needed to determine whether or not abiotic reductive dechlorination is occurring at a particular site, and its relative importance compared to microbial dechlorination under a variety of geochemical conditions.
Book Synopsis Synergistic Reductive Dechlorination of 1,1,1-trichloroethane and Trichloroethene and Aerobic Degradation of 1,4-dioxane by : Yihao Luo
Download or read book Synergistic Reductive Dechlorination of 1,1,1-trichloroethane and Trichloroethene and Aerobic Degradation of 1,4-dioxane written by Yihao Luo and published by . This book was released on 2018 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Widespread use of chlorinated solvents for commercial and industrial purposes makes co-occurring contamination by 1,1,1-trichloroethane (TCA), trichloroethene (TCE), and 1,4-dioxane (1,4-D) a serious problem for groundwater. TCE and TCA often are treated by reductive dechlorination, while 1,4-D resists reductive treatment. Aerobic bacteria are able to oxidize 1,4-D, but the biological oxidation of 1,4-D could be inhibited by TCA, TCE, and their reductive transformation products. To overcome the challenges from co-occurring contamination, I propose a two-stage synergistic system. First, anaerobic reduction of the chlorinated hydrocarbons takes place in a H2-based hollow-fiber "X-film" (biofilm or catalyst-coated film) reactor (MXfR), where "X-film" can be a "bio-film0" (MBfR) or an abiotic "palladium-film" (MPfR). Then, aerobic removal of 1,4-D and other organic compounds takes place in an O2-based MBfR. For the reductive part, I tested reductive bio-dechlorination of TCA and TCE simultaneously in an MBfR. I found that the community of anaerobic bacteria can rapidly reduce TCE to cis-dichloroethene (cis-DCE), but further reductions of cis-DCE to vinyl chloride (VC) and VC to ethene were inhibited by TCA. Also, it took months to grow a strong biofilm that could reduce TCA and TCE. Another problem with reductive dechlorination in the MBfR is that mono-chloroethane (MCA) was not reduced to ethane. In contrast, a film of palladium nano-particles (PdNPs), i.e., an MPfR, could the simultaneous reductions of TCA and TCE to mainly ethane, with only small amounts of intermediates: 1,1-dichloroethane (DCA) (~3% of total influent TCA and TCE) and MCA (~1%) in continuous operation. For aerobic oxidation, I enriched an ethanotrophic culture that could oxidize 1,4-D with ethane as the primary electron donor. An O2-based MBfR, inoculated with the enriched ethanotrophic culture, achieved over 99% 1,4-D removal with ethane as the primary electron donor in continuous operation. Finally, I evaluated two-stage treatment with a H2-based MPfR followed by an O2-MBfR. The two-stage system gave complete removal of TCA, TCE, and 1,4-D in continuous operation.
Book Synopsis Reductive Dechlorination Sustained by Microbial Chain Elongation by : Aide Robles
Download or read book Reductive Dechlorination Sustained by Microbial Chain Elongation written by Aide Robles and published by . This book was released on 2019 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: Trichloroethene (TCE) is a ubiquitous soil and groundwater contaminant. The most common bioremediation approach for TCE relies on the process of reductive dechlorination by Dehalococcoides mccartyi. D. mccartyi uses TCE, dichloroethene, and vinyl chloride as electron acceptors and hydrogen as an electron donor. At contaminated sites, reductive dechlorination is typically promoted by adding a fermentable substrate, which is broken down to short chain fatty acids, simple alcohols, and hydrogen. This study explored microbial chain elongation (MCE), instead of fermentation, to promote TCE reductive dechlorination. In MCE, microbes use simple substrates (e.g., acetate, ethanol) to build medium chain fatty acids and also produce hydrogen during this process. Soil microcosm using TCE and acetate and ethanol as MCE substrates were established under anaerobic conditions. In soil microcosms with synthetic groundwater and natural groundwater, ethene was the main product from TCE reductive dechlorination and butyrate and hydrogen were the main products from MCE. Transfer microcosms using TCE and either acetate and ethanol, ethanol, or acetate were also established. The transfers with TCE and ethanol showed the faster rates of reductive dechlorination and produced more elongated products (i.e., hexanoate). The microbial groups enriched in the soil microcosms likely responsible for chain elongation were most similar to Clostridium genus. These investigations showed the potential for synergistic microbial chain elongation and reductive dechlorination of chlorinated ethenes.
Book Synopsis Dechlorinating and Iron Reducing Bacteria Distribution in a Trichloroethene Contaminated Aquifer by : Carmen Lourdes Yupanqui Zaa
Download or read book Dechlorinating and Iron Reducing Bacteria Distribution in a Trichloroethene Contaminated Aquifer written by Carmen Lourdes Yupanqui Zaa and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Operable Unit 5 (OU 5) area of Hill Air Force Base currently has two trichloroethene-contaminated groundwater plumes underneath residential areas in Sunset and Clinton, Utah. Bioremediation by biological reductive dechlorination can be an important mechanism for the removal of chlorinated compounds from the plumes. The presence of suitable bacteria to carry on reductive dechlorination is the key in the bioremediation process. The goal of this study was to determine the distribution and population density of the 16S rRNA genes of Bacteria, Dehalococcoides ethenogenes, Desulfuromonas michiganensis, Geobacter spp and Rhodoferax ferrireducens-like bacteria, as well as the functional genes trichloroethene reductive dehalogenase (tceA) and vinyl chloride reductase gene (vcrA). This study also evaluated the influence of the physical-chemical properties of the OU 5 aquifer material on the observed bacterial distribution.
Book Synopsis Current Opinion in Biotechnology by :
Download or read book Current Opinion in Biotechnology written by and published by . This book was released on 1995 with total page 982 pages. Available in PDF, EPUB and Kindle. Book excerpt:
