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Phenol Biodegradation (phenol + biodegradation)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Biomass accumulation and clogging in trickle-bed bioreactors

AICHE JOURNAL, Issue 10 2004
Ion Iliuta
Abstract Excessive biomass formation in two-phase flow trickle-bed bioreactors induces clogging and leads to the progressive obstruction of the bed that is accompanied with a buildup in pressure drop and flow channeling. Currently, physical models linking the two-phase flow to the space-time evolution of biological clogging are virtually nonexistent. An attempt has been made with this contribution to fill in this gap by developing a unidirectional dynamic multiphase flow model based on the volume-average mass, momentum, and species balance equations. Phenol biodegradation by Pseudomonas putida as the predominant species immobilized on activated carbon was chosen as a case study to illustrate the consequences of formation of excessive amounts of biomass. Furthermore, in developing the transient model, the following basic processes were assumed to occur and have been accounted for in the mathematical model: oxygen transport from gas into liquid bulks, phenol, and oxygen transport from the liquid phase to the biofilm surface, simultaneous diffusion and reaction of phenol and oxygen within biofilm, as well as their simultaneous diffusion and adsorption within the porous supporting particles. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2541,2551, 2004 [source]

Artificial neural networks model for the prediction of steady state phenol biodegradation in a pulsed plate bioreactor

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2008
K Vidya Shetty
Abstract BACKGROUND: A recent innovation in fixed film bioreactors is the pulsed plate bioreactor (PPBR) with immobilized cells. The successful development of a theoretical model for this reactor relies on the knowledge of several parameters, which may vary with the process conditions. It may also be a time-consuming and costly task because of their nonlinear nature. Artificial neural networks (ANN) offer the potential of a generic approach to the modeling of nonlinear systems. RESULTS: A feedforward ANN based model for the prediction of steady state percentage degradation of phenol in a PPBR by immobilized cells of Nocardia hydrocarbonoxydans (NCIM 2386) during continuous biodegradation has been developed to correlate the steady state percentage degradation with the flow rate, influent phenol concentration and vibrational velocity (amplitude × frequency). The model used two hidden layers and 53 parameters (weights and biases). The network model was then compared with a Multiple Regression Analysis (MRA) model, derived from the same training data. Further these two models were used to predict the percentage degradation of phenol for blind test data. CONCLUSIONS: The performance of the ANN model was superior to that of the MRA model and was found to be an efficient data-driven tool to predict the performance of a PPBR for phenol biodegradation. Copyright © 2008 Society of Chemical Industry [source]

Modeling for batch phenol biodegradation with immobilized Alcaligenes faecalis

AICHE JOURNAL, Issue 4 2006
Xiaoqiang 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]

Modélisation de la cinétique de biodégradation de phénol par granules aérobies

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2008
Claudia Calvario-Rivera
Abstract Ce travail est consacré à la modélisation de la cinétique de biodégradation de phénol par granules aérobies. Ceux-ci ont été obtenus à partir de la culture à alimentation séquentielle d'un surnageant de boues activées sur une eau usée synthétique,; puis ils ont été acclimatés au phénol (100 mg/L). La biodégradation de différentes concentrations de phénol (40,1112 mg/L) a été étudiée en fioles agitées ensemencées avec des granules acclimatés. Un modèle de type Haldane a été sélectionné, qui permet de décrire de manière adéquate l'évolution de la concentration de phénol avec un seul jeu de paramètres. Ce modèle pourrait permettre de mieux comprendre la biodégradation de molécules toxiques telles que le phénol dans des réacteurs granulaires aérobies. This work describes a model of the biodegradation of phenol carried out by aerobic granules. These granules were obtained by culturing an activated sludge supernatant in a sequencing batch reactor fed with a synthetic waste water and subsequently, by acclimation to phenol (100 mg/L). The kinetics of phenol biodegradation by the aerobic granules was investigated over a wide range of initial phenol concentrations (40,1112 mg/L) in shake-flask cultures. A Haldane-type model was adjusted to the experimental results, which depicts successfully the phenol biodegradation profiles in the entire range of initial concentrations studied by using only one set of parameters. It is our view that the proposed model could contribute to the knowledge about the ability of aerobic granular systems to biodegrade toxic, inhibitory compounds such as phenol. [source]