Download or read book Benzene and Toluene Biodegradation with Different Dissolved Oxygen Concentrations written by Zhuolin Liu and published by . This book was released on 2015 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study reports on benzene and toluene biodegradation under different dissolved oxygen conditions, and the goal of this study is to evaluate and model their removal. Benzene and toluene were tested for obligate anaerobic degradation in batch reactors with sulfate as the electron acceptor. A group of sulfate-reducing bacteria capable of toluene degradation was enriched after 252 days of incubation. Those cultures, originated from anaerobic digester, were able to degrade toluene coupled to sulfate reduction with benzene coexistence, while they were not able to utilize benzene. Methanogens also were present, although their contribution to toluene biodegradation was not defined. Aerobic biodegradation of benzene and toluene by Pseudomonas putida F1 occurred, and biomass production lagged behind substrate loss and continued after complete substrate removal. This pattern suggests that biodegradation of intermediates, rather than direct benzene and toluene transformation, caused bacterial growth. Supporting this explanation is that the calculated biomass growth from a two-step model basically fit the experimental biomass results during benzene and toluene degradation with depleted dissolved oxygen. Catechol was tested for anaerobic biodegradation in batch experiments and in a column study. Sulfate- and nitrate-reducing bacteria enriched from a wastewater treatment plant hardly degraded catechol within 20 days. However, an inoculum from a contaminated site was able to remove 90% of the initial 16.5 mg/L catechol, and Chemical Oxygen Demand was oxidized in parallel. Catechol biodegradation was inhibited when nitrite accumulated, presumably by a toxic catechol-nitrite complex. The membrane biofilm reactor (MBfR) offers the potential for biodegrading benzene in a linked aerobic and anaerobic pathway by controlling the O2 delivery. At an average benzene surface loading of 1.3 g/m2-day and an average hydraulic retention time of 2.2 day, an MBfR supplied with pure O2 successfully achieved 99% benzene removal at steady state. A lower oxygen partial pressure led to decreased benzene removal, and nitrate removal increased, indicating multiple mechanisms, including oxygenation and nitrate reduction, were involved in the system being responsible for benzene removal. Microbial community analysis indicated that Comamonadaceae, a known aerobic benzene-degrader and denitrifier, dominated the biofilm at the end of operation.
Download or read book Biodegradation of Benzene and a BTX Mixture Using Immobilized Activated Sludge written by Mayur Padamshi Lodaya and published by . This book was released on 1989 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerobic biodegradation of benzene was studied using activated sludge immobilized in calcium alginate (immobilization by entrapment), and also attached to a silica based catalyst.support (immobilization by attachment). Hydrogen peroxide was used as a source of dissolved oxygen to eliminate physical removal of benzene due to aeration. Abiotic losses of benzene were accounted for. A recirculation reactor, run in both batch and continuous feed mode, was used to determine the kinetic parameters. The system response was examined by tollowing changes in benzene concentration, flow rate, and biomass loading. The system was modeled mathematically and the kinetic parameters were determined. Biological removal of a mixture of benzene, toluene and o, m and pxylene (BTX) was also studied. In a typical batch experiment starting with 100 ppm benzene, the substrate utilization rate (kM), when expressed per unit weight of dry catalyst, had a value of 0.4453 ppm/h/g dry beads for the alginate system, and 0.067 ppm/h/g dry beads for the celite catalyst carrier. Activated sludge was characterized for biodegradation of benzene. Isolations were done for unacclimated, acclimated and end run samples. About 67% of the isolates could be assigned to a genus. These were Bacillus, Microbacterium', Plesiomonas, Kurthia, Klebsiella, Lactobacillusj and Pseudomonas. From among the fifteen isolates found in the end run group, - an isolate identified as Pseudomonas was established as a primary degrader of benzene.
Download or read book Experimental and Modeling Approaches to Evaluating Anaerobic Biodegradation of Petroleum contaminated Groundwater written by Madeline E. Schreiber and published by . This book was released on 1999 with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Water resources Investigations Report written by and published by . This book was released on 1996 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Photodegradation of N Methyldiethanolamine and Benzene Toluene Xylene written by Wan Azelee Wan Abu Bakar and published by LAP Lambert Academic Publishing. This book was released on 2012-04 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: N-methyldiethanolamine (N-MDEA) is used in the natural gas refinery process to remove carbon dioxide (CO2) and hydrogen sulphide (H2S) and was discharged as pollutants with other aromatic hydrocarbons such as Benzene-Toluene-Xylene (BTX) compounds. The small leakage of this component will contaminate the environment and lead to heavy water pollution. These dangerous materials that polluted the water system can effect the aquatic life by consume dissolved oxygen. Thus, some effort must be carried out to overcome these problems. In this study, photocatalytic process has been introduced for the treatment of these compounds using coupled ZnO/TiO2, WO3/TiO2 and ternary ZnO/WO3/TiO2 which were prepared via sol-gel method. The parameters studied in this research were ratio of photocatalyst used, the effect of sonication and ozonation processes, various initial concentrations of substrate and different UV wavelength for the degradation of N-MDEA and BTX compounds in aqueous system. This research should help and provide a new insight to the scientist worldwide in waste water treatment or anyone else who may be considering utilizing this techniques for green environmental efforts.
Download or read book Intrinsic Bioremediation written by Robert E. Hinchee and published by . This book was released on 1995 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: An international group of researchers and engineers discuss using natural attenuation to degrade contaminants and thereby remediate soils and groundwater. This volume describes laboratory studies and field demonstrations in support of subsurface remediation at military, manufactured gas plant, landfill, petroleum spill, and other sites. The contaminants of concern include benzene, toluene, ethyl-benzene, and xylenes (BTEX); naphthalene; trichloroethene; trichlorethane; and perchloroethylene. Analytical methods for assessing the potential for natural attenuation (passive bioremediation) at a given site and for confirming and documenting efficacy are discussed.
Download or read book Assessment of Intrinsic Bioremediation of Gasoline Contamination in the Shallow Aquifer Laurel Bay Exchange Marine Corps Air Station Beaufort South Carolina written by James E. Landmeyer and published by . This book was released on 1996 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Natural Attenuation for Groundwater Remediation written by Commission on Geosciences, Environment, and Resources and published by National Academies Press. This book was released on 2000-08-31 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past decade, officials responsible for clean-up of contaminated groundwater have increasingly turned to natural attenuation-essentially allowing naturally occurring processes to reduce the toxic potential of contaminants-versus engineered solutions. This saves both money and headaches. To the people in surrounding communities, though, it can appear that clean-up officials are simply walking away from contaminated sites. When is natural attenuation the appropriate approach to a clean-up? This book presents the consensus of a diverse committee, informed by the views of researchers, regulators, and community activists. The committee reviews the likely effectiveness of natural attenuation with different classes of contaminants-and describes how to evaluate the "footprints" of natural attenuation at a site to determine whether natural processes will provide adequate clean-up. Included are recommendations for regulatory change. The committee emphasizes the importance of the public's belief and attitudes toward remediation and provides guidance on involving community stakeholders throughout the clean-up process. The book explores how contamination occurs, explaining concepts and terms, and includes case studies from the Hanford nuclear site, military bases, as well as other sites. It provides historical background and important data on clean-up processes and goes on to offer critical reviews of 14 published protocols for evaluating natural attenuation.
Download or read book Effects of Air Sparging on a Geochemically Heterogeneous Groundwater System written by Ingrid L. Ekstrom and published by . This book was released on 2003 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Toxicological Profile for Benzene written by and published by . This book was released on 1997 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biodegradation written by and published by . This book was released on 1995 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 2012-10-04 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.
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1991 with total page 884 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Remediation Engineering written by Suthan S. Suthersan and published by CRC Press. This book was released on 1996-10-24 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: In many cases, the application of in situ technologies evolved as a necessity from a cost perspective. However, the basic understanding of the mechanisms and theory behind these technologies was treated as a "black box." Although we have seen some tremendous successes in the application of remediation technologies over the past several years, we have also seen many cases in which a technology has been incorrectly or inappropriately applied. In most cases, this misapplication has been the result of a poor understanding of the basic concepts and mechanisms behind the technologies. Without proper understanding, the potential for misapplication of technologies remains a serious economic and technical threat.
Download or read book Groundwater Geochemistry written by William J. Deutsch and published by CRC Press. This book was released on 2020-11-25 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Groundwater Geochemistry: Fundamentals and Applications to Contamination examines the integral role geochemistry play s in groundwater monitoring and remediation programs, and presents it at a level understandable to a wide audience. Readers of all backgrounds can gain a better understanding of geochemical processes and how they apply to groundwater systems. The text begins with an explanation of fundamental geochemical processes, followed by a description of the methods and tools used to understand and simulate them. The book then explains how geochemistry applies to contaminant mobility, discusses remediation system design, sampling program development, and the modeling of geochemical interactions. This clearly written guide concludes with specific applications of geochemistry to contaminated sites. This is an ideal choice for readers who do not have an extensive technical background in aqueous chemistry, geochemistry, or geochemical modeling. The only prerequisite is a desire to better understand natural processes through groundwater geochemistry.
Download or read book CRREL Report written by Cold Regions Research and Engineering Laboratory (U.S.) and published by . This book was released on 1984 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Report written by Cold Regions Research and Engineering Laboratory (U.S.) and published by . This book was released on 1984 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
