Download or read book Kinetics of Biodegradation of Chlorinated Organics in Activated Sludge Type Systems written by Nadim Antun Shamat and published by . This book was released on 1978 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biodegradation of Chlorinated Organics by Activated Sludge Microorganisms and Modeling of Biodegradation Kinetics written by Chung Jik Kim and published by . This book was released on 1982 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Factors Influencing the Biodegradation Kinetics of Toxic Organic Compounds in Activated Sludge Systems written by Charles Vijay Anselm and published by . This book was released on 1998 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: When phenol was removed from the feed stream the measured kinetic parameters for phenol significantly reduced, and the kinetic parameters for 4CP increased. When both compounds were removed from the feed the measured kinetic parameters for phenol and 4CP reduced significantly. The results observed from this research have shown that rate of biodegradation of individual organic compounds is significantly influenced by changes in operational conditions. The findings of this research is a significant contribution towards the understanding of the factors that affect the rate of biodegradation kinetics of toxic organic compounds in activated sludge treatment systems.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1998 with total page 950 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chlorinated Organics Removal from Contaminated Soil and Groundwater by Microorganisms written by Chung Jik Kim and published by . This book was released on 1986 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development and Calibration of Bio kinetic Models for Organic Carbon and Nitrogen Biodegradation in an Aerobic Activated Sludge System written by Muhammad Azizul Hoque and published by . This book was released on 2010 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: Substrate removal mechanisms in a mixed culture of an activated sludge system are still a mystery that researchers have been trying to unravel by proposing and developing models to interpret the observed experimental data. Activated Sludge Model Number 1 (ASM1) was first introduced to better understand the biochemical mechanisms during carbon and nitrogen oxidation and was based on the assumption that the external substrate is consumed only for biomass growth. This model ignored the formation of intracellular polymers (storage products) in the biomass cell, though several researchers observed the phenomenon of storage of carbon sources and the significant role it played in the carbon removal process. As a consequence, the Activated Sludge Model Number 3 (ASM3) was formulated assuming that all the easily biodegradable substrate is first stored internally during the feast phase before being used for growth during famine conditions. However, experimental observations proved that both storage and growth occur simultaneously during the feast phase. Consequently, the simultaneous storage and growth (SSAG) model was developed as an extension to ASM3 specifically to gain an in-depth understanding of the carbon oxidation process. While considerable investigation has been focused on model calibration using respirometric measurements of the oxygen uptake rate (OUR) during the aerobic biodegradation of substrate, model-based interpretation of titrimetric measurements has been limited. In biological systems, the oxygen consumption and corresponding pH changes occur simultaneously and can be easily monitored using respirometric and titrimetric experimental observations respectively. Attempts were, therefore, made to calibrate ASM1 using titrimetric measurements. During the subsequent successful development, consideration was given to the pH effects of carbon uptake, ammonia uptake for growth, CO2 production from carbon metabolism and the nonlinear carbon dioxide transfer rate (CTR) due to stripping. While respirometry was successfully used to calibrate every proposed new model, the interpretation of titrimetric measurements, however, was always based on ASM1, using calibration substrates such as acetate and ammonium. The SSAG model, developed in the year 2005, proposed an improved kinetic expression for the degradation of storage products under famine conditions. It was successfully calibrated using on-line respirometric measurements and validated using off-line storage products measurements with acetate used as a calibration substrate. However it failed to explain the titrimetric behavior of the substrate biodegradation process. While in most cases the above models were calibrated using simple synthetic substrates, the application of these models for complex substrates was not investigated. Therefore, in this dissertation, the biodegradation kinetics for different substrates like acetate (simple carbon source), sodium dodecyl sulfate (relatively complex carbon source), ammonium (simple nitrogen source), urea (relatively complex nitrogen source) and glutamic acid (combination of carbon and nitrogen) were investigated. A titrimetric respirometer, established in the Water-waste laboratory in the Faculty of Engineering and Surveying, University of Southern Queensland, Australia, was used to conduct batch experiments in order to monitor substrate biodegradation process in an aerobic activated sludge system. Both the dissolved oxygen and the pH control data were logged with the Labview software package. A spreadsheet program was used to calculate the oxygen uptake rate and the proton production/consumption rate from the raw measurements. During batch experiments, the biodegradation of all five test substrates showed unique respirometric and titrimetric behaviors indicating that each of these compounds is biodegraded using distinctive mechanisms with the involvement and coordination of different bacterial populations. The pattern of OURs were observed varying from substrate to substrate describing the characteristics of test compounds. The titrimetric profiles were also different for different substrates biodegradation reflecting the on-going biochemical reaction of respective substrate in activated sludge system. While acetate biodegradation, for example, caused proton consumption (at pH 7.8) in the liquid medium, proton production was noted under feast conditions when either sodium dodecyl sulfate or glutamic acid was used as a test substrate. An in-depth revision of the existing activated sludge models was completed and the models were assessed using experimental observations. An improved bio-kinetic model which includes both the oxygen and proton balances for the biodegradation of each of the test substrates was then developed. In addition, the substrates biodegradation pathway and the non-linear CO2 transfer process were considered during the modeling. For proper model evaluation, the proposed model was calibrated using varying initial substrate concentrations and pH levels. In addition, three different calibration approaches: using respirometric measurements alone, using titrimetric measurements alone and using combined respirometric-titrimetric measurements, were applied during the study. The estimation of model parameters was undertaken using non-linear techniques utilizing the algorithms in the optimisation toolbox (MATLAB). For the biodegradation of each test substrate, the proposed model was successfully calibrated using both the respirometric and titrimetric behaviors in the activated sludge system. The estimated model parameters showed consistent results for all three calibration approaches thereby confirming the precision of the proposed model. The parameter estimation errors (calculated for 95% confidence intervals) as well as the mean squared errors for the different calibration approaches were quite reasonable and confirmed the statistical soundness of the proposed model. In addition, the proposed model was validated using off-line measurements. This dissertation presents an in-depth explanation of how the proposed models interpret the biodegradation processes and how the model parameters vary for different substrates in an activated sludge system. The results will be helpful in further refining current models that can contribute to the optimization of the design operation and enhanced performance of full scale wastewater treatment plants.
Download or read book Investigations of Biodegradability and Toxicity of Organic Compounds written by Jan Dojlido and published by . This book was released on 1979 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1991 with total page 882 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Degradation Kinetics of Chlorinated Aromatic Compounds in Saturated Subsurface Environments written by and published by . This book was released on 1990 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Influence of Kinetic and Metabolic Selection on 17alpha ethinylestradiol Biodegradation in Activated Sludge Wastewater Treatment Systems written by Ryan M. Ziels and published by . This book was released on 2013 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The potent endocrine-disrupting estrogen hormone, 17alpha-ethinylestradiol (EE2), is primarily removed via biodegradation in municipal wastewater treatment plant (WWTP) activated sludge (AS) processes; however, reported EE2 removal efficiencies in AS WWTPs vary widely. A hypothesis of this research was that EE2 biodegradation kinetics vary as a function of AS process and reactor designs, which select for different microbial population compositions. Bench-scale AS reactors treating municipal wastewater and estrogens at ng/L concentrations were operated to simulate kinetic population selection with high initial food-to-biomass ratio feeding conditions (high-F/Mf) or low substrate growth conditions (low-F/Mf), as well as metabolic selection with substrate uptake and growth under aerobic, anaerobic, and anoxic conditions. The latter two metabolic selectors resulted in enhanced biological phosphorus removal and biological nitrogen removal, respectively. A pseudo first-order biodegradation model was used to examine the effects of metabolic and kinetic selective pressures on EE2 biodegradation kinetics. Aerobic low-F/Mf reactors experienced pseudo first-order EE2 biodegradation rate coefficients (kb) that were 1.4 to 2.2 times greater than high-F/Mf aerobic selectors operated in parallel, suggesting that kinetic selection influences EE2 biodegradation activity in AS systems. No significant difference was observed in the EE2 kb of high-F/Mf metabolic bioselectors (aerobic-only, anoxic/aerobic and anaerobic/aerobic). However, metabolic selection reduced the EE2 kb of a low-F/Mf anoxic/aerobic reactor by 40% relative to a low-F/Mf aerobic reactor, demonstrating that the redox state of growth conditions may affect microbial EE2 biodegradation kinetics in AS. The results of this study suggest that operating conditions in which microbial growth occurs aerobically at low substrate concentrations improve EE2 biodegradation kinetics in AS systems, possibly due to the growth of K-strategist heterotrophs capable of more efficient EE2 biodegradation at low ng/L concentrations. Supplementary files to this dissertation include Appendix B, which is a Microsoft Excel file that provides supporting data to the presented research results.
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 Toxic Chlorinated Compounds written by Bhaskar Ballapragada and published by . This book was released on 1998 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determination of Biodegradation Kinetics of Select Pharmaceuticals and Personal Care Products in an Activated Sludge System Through Respirometry written by Joseph R. Stonesifer and published by . This book was released on 2012 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bioremediation of Chlorinated Solvents written by Robert E. Hinchee and published by . This book was released on 1995 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil and groundwater contamination stemming from the release of various chlorinated compounds into the environment is a significant and difficult site remediation challenge. The articles in this collection discuss the use of aerobic and anaerobic biological degradation to dehalogenate sites contaminated with pesticides and chlorinated solvents such as trichloroethylene, tetrachloroethene, tetrachloromethene, perchloroethylene, carbon tetrachloride, pentachlorophenol, and chlorinated benzene. Bench- and field-scale studies of the biological processes associated with in situ dechlorination of soil and aquifers are described. Discussed are the uses of microcosm studies and numerical simulation of dechlorination to manage system operation. Site characteristics (e.g., hydraulic properties, temperature, nitrogen availability) and their effect on the stability of the methanotrophic community are examined. Methods discussed include the use of air venting, alternative electron donors, biofilm reactors, surfactants, municipal digester sludge, iron enhancement, and sulfate reduction to improve conditions for the microbial consortia that effect dechlorination.
Download or read book Engineered Approaches to in Situ Bioremediation of Chlorinated Solvents written by and published by DIANE Publishing. This book was released on 2000 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Dynamic Model of the Completely Mixed Activated Sludge and Final Clarification Processes written by David LaVerne Ching and published by . This book was released on 1980 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:
