Download or read book Enhanced Degradation of Polychlorinated Biphenyls written by Bernard Gibbs and published by LAP Lambert Academic Publishing. This book was released on 2011-03 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is a worldwide initiative to remove polychlorinated biphenyls (PCBs) from the environment because of their potential hazard. Animal experiments have shown they can produce liver damage, developmental defects and even cancer. Thirty per cent of the 310,000 tons of PCBs that have been produced globally are now considered as persistent toxicants in the environment. To date, only 4% have been successfully treated. Although a number of technologies are in existence for the treatment of persistent organic pollutants (POPs), they do have several drawbacks including the production of toxic volatiles in incinerators and high cost associated with these procedures. On the other hand, successful bioremediation is relatively inexpensive, as shown for polyaromatic hydrocarbons (PAH) degradation, with the added advantages of being able to be carried out in situ. In this study, preliminary experiments demonstrated that certain surfactants enhance PCB degradation in aqueous solution in the presence of enzymes, in a concentration-dependent manner. These surfactants have not been previously reported as enhancers in PCB degradation.
Download or read book Enhanced Degradation of Polychlorinated Biphenyls by Surfactants and a Dioxygenase Enzyme Complex written by Bernard F. Gibbs and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is a worldwide initiative to remove polychlorinated biphenyls (PCBs) from the environment because of their potential hazard. Animal experiments have shown they can produce liver damage, developmental defects and even cancer. Thirty per cent of the 310,000 tons of PCBs that have been produced globally are now considered as persistent toxicants in the environment. To date, only 4% have been successfully treated. Although a number of technologies are in existence for the treatment of persistent organic pollutants (POPs), they do have several drawbacks including the production of toxic volatiles in incinerators and high cost associated with these procedures. On the other hand, successful bioremediation is relatively inexpensive, as shown for polyaromatic hydrocarbons (PAH) degradation, with the added advantages of being able to be carried out in situ . In this study, preliminary experiments demonstrated that certain surfactants enhance PCB degradation in aqueous solution in the presence of enzymes, in a concentration-dependent manner. These surfactants have not been previously reported as enhancers in PCB degradation. Conditions were optimized before experiments with soil samples were performed. A soil sample (free of PCBs) was spiked with varying amounts of PCBs and internal standards. Samples were mixed at various speeds, temperatures, incubation periods and concentrations of surfactants, before the metabolites were extracted and mass analyzed. An aged PCB-contaminated soil sample was also studied. PCBs extraction recoveries for the spiked samples two hours after exposure to the toxicants were 93% whereas average recovery from the samples extracted after 60 days of toxicant exposure was 67%. Within 2 hours of incubation, 47, 28 and 14% of PCBs were biodegraded from the contaminated sample by the addition of surfactin, rhamnolipids and octyl glucoside respectively, at concentrations above their critical micelle concentrations. If the soil composition and mechanism for removal at a contaminated site are fully understood, in situ biodegradation can be exploited.
Download or read book Degradation of Trichloroethylene TCE and Polychlorinated Biphenyls PCBs by Fe and Fe Pd Bimetals in the Presence of Surfactants and Cosolvents written by and published by . This book was released on 1997 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surfactants and cosolvents are being used to enhance the removal of dense non-aqueous phase liquids (DNAPL) such as trichloroethylene (TCE) and polychlorinated biphenyls (PCBS) from contaminated soils. However, the waste surfactant solution containing TCE and PCBs must be treated before it can be disposed. This study evaluated the use of zero-valence iron and palladized iron fillings on the dechlorination of TCE and a PCB congener in a dihexylsulfosuccinate surfactant solution. Batch experimental results indicated that TCE can be rapidly degraded by palladized iron filings with a half-life of 27.4 min. PCB was degraded at a slower rate than TCE with a half-life ranging from 100 min to 500 min as the concentration of surfactant increased. In column flow-through experiments, both TCE and PCBs degrade at an enhanced rate with a half-life about 1.5 and 6 min because of an increased solid to solution ratio in the column than in the batch experiments. Results of this work suggest that Fe-Pd filings may be potentially applicable for ex-situ treatment of TCE and PCBs in the surfactant solutions that are generated during surfactant washing of the contaminated soils.
Download or read book Characterization of Soil Bacterial Communities Involved in Polychlorinated Biphenyl Remediation written by Ekawan Luepromchai and published by . This book was released on 2001 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Enhancement of Site Specific Anaerobic Reductive Dechlorination of Polychlorinated Biphenyls written by Matthew John Zwiernik and published by . This book was released on 1998 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Enhancing the Biodegradation of Polychlorinated Biphenyls PCBs Through Elemental Iron FeO Addition written by Jason Peter Rysavy and published by . This book was released on 2002 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Degradation of Polychlorinated Biphenyls by White rot Fungi written by Diane Dietrich and published by . This book was released on 1995 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Enhanced Biotransformation and Biodegradation of Polychlorinated Biphenyls in the Presence of Aminopolysaccharides written by K. Fujisaki and published by . This book was released on 1988 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fate analysis predictions of agricultural or industrial source toxicants in aquatic or marine environments can be affected by the presence or absence of adapted (preexposed) microbial populations and amenable substrates for cometabolic or cooxidative biotransformation. Polychlorinated biphenyls (PCBs) were evaluated in controlled laboratory microcosm systems in the presence of the aminopolysaccharide polymer chitin. Toxicants evaluated included the commercial Aroclors 1232, 1248, and 1254. Crosscouplings of each PCB mixture and polymer were noted, resulting in an optimization of epiphytic microbial metabolic activity. Significant primary degradation was noted for the lesser chlorinated biphenyls, that is, Aroclor 1232. Gas chromatography analysis of Aroclor 1248 and 1254 showed several tetra and penta isomers remaining. However, when polymer epiphytic populations were predominantly adapted microbial strains, that is, a Pseudomonas species and an Acinetobacter species, additional refractile isomers were metabolized. A comparison of kinetic rate constants based on biotransformation of each commercial mixture showed significant changes in halflife as correlated to isomer mixture, available polymer, and microbial inoculation.
Download or read book Metabolism and Genetics of Chlorobenzoate Degradation written by William James Hickey and published by . This book was released on 1990 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Use of Root colonizing Recombinant Bacteria to Enhance Rhizosphere Degradation of Polychlorinated Biphenyls written by Amanda Wallis Gilbertson and published by . This book was released on 2006 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, Sinorhizobium meliloti which has a well characterized nodulating relationship with Medicago sativa (alfalfa). S. meliloti 1021 was engineered with the bph genes. The recombinant S. meliloti retained similar growth rates as the wild-type strain. The engineered S. meliloti strains grew on biphenyl and monochlorobiphenyl.
Download or read book Amine enhanced Photodegradation of Polychlorinated Biphenyls written by and published by . This book was released on 1982 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dehalogenation written by Max M. Häggblom and published by Springer Science & Business Media. This book was released on 2007-05-08 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: Halogenated organic compounds constitute one of the largest groups of environmental chemicals. The industrial production of new halogenated organic compounds has increased throughout the last century peaking in the 1960s, and continuing in widespread use today. Organohalides are integral to a variety of industrial applications, including use as solvents, degreasing agents, biocides, pharmaceuticals, plasticizers, hydraulic and heat transfer fluids, and intermediates for chemical synthesis, to name a few. It is important to recognize the beneficial aspects of halogenated organic compounds, as well as their potentially deleterious impact on the environment and health. Recognition ofthe adverse environmental effects ofmanytypes oforganohalide compounds has led to efforts to reduce or eliminate the most problematic ones. Although organohalide compounds are typically considered to be anthropogenic industrial compounds, they have their counterpart in several thousands of natural biogenic and geogenic organohalides, representing most classes of organic chemicals. Natural sources account for a significant portion of the global organohalogen budget. This volume authored by recognized experts in the field provides a current perspective on how both natural and synthetic organohalides are formed and degraded, and how these processes are incorporated into a global halogen cycle. The focus is on microbial processes, since these play a major role both in the production and degradation, i. e. , cycling of halogenated organic compounds inthe environment. This book is organized into five parts. Part I, Introduction, provides a global perspective on the issues of organohalides and their fate in the environment.
Download or read book Amine enhanced photodegradation of polychlorinated biphenyls written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Degradation of Polychlorinated Biphenyls by Three Different Microbial Mixed Cultures written by Robert Raymond Clark and published by . This book was released on 1978 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microbial Degradation of Polychlorinated Biphenyls and Alkylated Polycyclic Aromatic Hydrocarbons written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Attenuation of Water soluble Polychlorinated Biphenyls by Earth Materials written by Robert Alfred Griffin and published by . This book was released on 1980 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microbial Metabolism of Xenobiotic Compounds written by Pankaj Kumar Arora and published by Springer. This book was released on 2019-06-27 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: Xenobiotic compounds including pesticides, nitrophenols, pyridine, polycyclic aromatic compounds and polychlorinated biphenyls are widely spread in environment due to anthropogenic activities. Most of them are highly toxic to living beings due to their mutagenic and carcinogenic properties. Therefore, the removal of these compounds from environment is an essential step for environmental sustainability. Microbial remediation has emerged as an effective technology for degradation of these xenobiotic compounds as microorganisms have unique ability to utilize these compounds as their sole source of carbon and energy. The primary goal of this book is to provide detailed information of microbial degradation of many xenobiotic compounds in various microorganisms.
