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Biodegradation Processes (biodegradation + process)
Selected AbstractsAssessment of naphthalene biodegradation efficiency of Pseudomonas and Burkholderia strains tested in soil model systems,JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2006Andrei E Filonov Abstract The kinetic parameters of the naphthalene degradation process performed by indigenous and introduced microorganisms were studied in soil model systems. The introduction of active naphthalene-degrading strains Pseudomonas putida BS3701 and G7 in soil model systems accelerated the naphthalene destruction process by a factor of three to four. Moreover, the addition of salicylate (0.1 mg g,1 dry soil) to the systems containing the introduced microbial strains again doubled the rate of the naphthalene degradation process. To provide a quantitative assessment of the naphthalene biodegradation process, a mathematical model describing the bacterial growth, the consumption of the naphthalene, the production and subsequent consumption of naphthalene cleavage products, and the consumption of organic soil substances in soil model systems was developed. An approach for assessment of the degradation efficiency of low solubility polycyclic aromatic hydrocarbon provided by bacteria of genera Pseudomonas and Burkholderia in soil was suggested. The approach will enable comparison and selection of the most active degraders, which have the potential for application in biotechnologies for cleaning of soils contaminated by polycyclic aromatic hydrocarbons. Copyright © 2005 Society of Chemical Industry [source] Analysis of the Activated Sludge Process in an MBR under Starvation ConditionsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 3 2006M. Vukovic Abstract An aerobic membrane bioreactor (MBR) at complete biomass retention was studied over a period of time under starvation conditions. Kinetic parameters were determined in a no-feed batch test. The decay rate of activated sludge, kd = 0.05,d,1, was determined by tracking the decrease of MLSS. The ratio of MLVSS/MLSS was in the range 0.76,0.85. The pH values were between 7.02 and 8.23. As a function of different initial concentrations of MLSS, specific nitrification rates qN, decreased from 4.23 to 0.02,mg-N/(g,MLVSS,d) and specific biodegradation rates qb increased from 0.23 to 1.90,mg-COD/(g,MLVSS,d). From experimental data the kinetic constants for respiration, which followed Monod kinetics, were determined as qO2max = 9.8,mg-O2/(g,MLVSS,h), Kx = 2.9,g/dm3. Additionally, a linear correlation between MLSS and mean floc size was found to exist during the biodegradation process. [source] Enhancement in mineralization of some natural refractory organic compounds by ozonation,aerobic biodegradationJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2006Devendra P Saroj Abstract Two schemes, the first involving ozonation followed by final aerobic biodegradation (phase I experiments), and the second involving initial aerobic biodegradation, followed by ozonation and subsequent final aerobic biodegradation (phase II experiments), were examined for enhanced mineralization of refractory model compounds, viz. gallic acid, tannin and lignin. In all cases, and irrespective of the applied scheme, chemical oxygen demand (COD), total organic carbon (TOC), COD/TOC ratio, and specific UV absorbance at 280 nm attributed to the model compounds decreased with application of increasing ozone dose. The residual organic matter remaining after ozonation exhibited enhanced aerobic biodegradability in all cases. Further, in all cases and irrespective of the applied scheme, the overall amount of COD and TOC removed through the combination of ozonation and biodegradation processes increased with increase in ozone dose for all three model compounds, and more than 90% COD removal could be achieved with an ozone dose of 3 mg ozone absorbed per mg initial TOC, as compared with approximately 40% COD removal when no ozone was applied. Treatment by the first scheme resulted in the fraction of starting COD removed through biodegradation decreasing with increase in ozone dose in all cases, while this fraction increased or remained constant during treatment using the second scheme. In the case of tannin and lignin, similar overall COD removal could be achieved at lower ozone doses using scheme II. Due to incorporation of the initial aerobic biodegradation step in scheme II, the ozone requirement for additional mineralization, ie mineralization over and above that achieved by aerobic biodegradation, was also lower than that in scheme I. Copyright © 2005 Society of Chemical Industry [source] Modeling for batch phenol biodegradation with immobilized Alcaligenes faecalisAICHE JOURNAL, Issue 4 2006Xiaoqiang Jia Abstract Intrinsic cell growth and phenol biodegradation kinetics of Alcaligenes faecalis were studied in shaking flasks. Batch phenol biodegradation experiments were carried out in a 7.5 L fermentor with immobilized Alcaligenes faecalis in polyurethane foams. A double-layer reaction-diffusion model was developed to describe the dynamic behaviors of batch phenol biodegradation processes. Phenol degradation (within the cell-immobilized polyurethane foams as well as in the main liquid phase) and cell growth (within the cell-immobilized polyurethane foams only) at different initial phenol concentrations were simulated and analyzed in terms of both biodegradation time and layer radius course. The good agreement between the model simulations and the experimental measurements for phenol degradation in the main liquid phase validates the proposed double-layer reaction-diffusion model. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source] Limitations of mass spectrometric methods for the characterization of polydisperse materials,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2010Alan A. Herod This paper is a review of work on the characterization of coal liquids and petroleum residues and asphaltenes over several decades in which various mass spectrometric methods have been investigated. The limitations of mass spectrometric methods require exploration in order to understand what the different analytical methods can reveal about environmental pollution by these kinds of samples and, perhaps more importantly, what they cannot reveal. The application of mass spectrometry to environmental problems generally requires the detection and determination of the concentration of specific pollutants released into the environment by accident or design. The release of crude petroleum or coal liquids into the environment can be detected and tracked during biodegradation processes through specific chemicals such as alkanes or polyaromatic hydrocarbons (PAHs). However, petroleum asphaltenes are polydisperse materials of unknown mass range and chemical structures and, therefore, there are no individual chemicals to detect. It is necessary to determine methods of detection and the ranges of mass of such materials. This can only be achieved through fractionation to reduce the polydispersity of the initial sample. Comparison of mass spectrometric results with results from an independent analytical method such as size-exclusion chromatography with a suitable eluent is advisable to confirm that all the sample has been detected and mass discrimination effects avoided. Copyright © 2010 John Wiley & Sons, Ltd. [source] | ||||||||||