oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Simple models for the continuous aerobic biodegradation of phenol in a packed bed reactor
Gerrard, Andrew Mark;Páca Júnior, Jan;Kostecková, Alena;Páca, Jan;Stiborová, Marie;Soccol, Carlos Ricardo;
Brazilian Archives of Biology and Technology , 2006, DOI: 10.1590/S1516-89132006000500018
Abstract: this paper proposes the use of a preliminary, phenol removal step to reduce peak loads arriving at a conventional effluent plant. a packed bed reactor (pbr) using polyurethane foam, porous glass and also cocoa fibres as the inert support material was used. experiments have been carried out where the flow-rates, plus inlet and outlet phenol concentrations were measured. a simple, plug-flow model is proposed to represent the results. zero, first order, monod and inhibited kinetics rate equations were evaluated. it was found that the monod model gave the best fit to the experimental data and allowed linear graphs to be plotted. the monod saturation constant, k, is approximately 50 g m-3, and ka is around 900 s-1.
Continuous Biosynthesis of Farnesyl Laurate in Packed Bed Reactor: Optimization using Response Surface Methodology  [PDF]
N.K. Rahman,A.H. Kamaruddin,M.H. Uzir
Journal of Applied Sciences , 2010,
Abstract: This study is aimed to develop an optimal continuous procedure for lipase-catalyzed esterification of farnesol with lauric acid in a packed bed reactor in order to investigate the possibility of large scale production. Response Surface Methodology (RSM) based on Central Composite Rotatable Design (CCRD) was used to optimize the two important reaction variables which are packed bed height (cm) and substrate flow rate (ml/min) for the esterification of farnesol with lauric acid in a continuous packed bed reactor. The optimum conditions for the esterification of farnesol with lauric acid were found as the following: 18.18 cm packed bed height and 0.9 mL min-1 substrate flow rate. The optimum molar conversion of lauric acid to farnesyl laurate was 98.07±0.82%.
Effect of Copper and Iron on Acidogenic Biomass in an Anaerobic Packed Bed Reactor  [PDF]
Gonzalo M. Figueroa-Torres, Maria T. Certucha-Barragán, Francisco J. Almendariz-Tapia, Onofre Monge-Amaya, Evelia Acedo-Félix, Martín I. Pech-Canul, Ana L. Leal-Cruz, Carlos I. VillaVelázquez-Mendoza
Advances in Bioscience and Biotechnology (ABB) , 2014, DOI: 10.4236/abb.2014.56066
Abstract:

The aim of this study was to evaluate the effect of copper and iron on acidogenic biomass immobilized on clinoptilolite in an anaerobic packed bed reactor. Copper and iron were fed to the reactor at concentrations of 100 and 300 mg·L-1, respectively. Both metal ions had insignificant inhibitory effect over the metabolism of the biomass, specifically, on substrate consumption and production of volatile fatty acids (VFAs). The microstructural characterization of the biofilm by Scanning Electron Microscopy showed no effect on the morphology of the microorganisms after the metals treatment. Copper and iron removal was also measured in the reactor, achieving a breakthrough time of 3 days, during which removal efficiencies were higher than 90%. It was also observed that the biomass had a greater affinity for copper. The results indicate that acidogenic biomass can be used effectively as a sorbent agent. The pollution of river-streams with heavy metals—mainly copper and iron—was one of the most compelling motivations for conducting this investigation. The San Pedro River Basin, a trans-boundary river that originates near the mining town of Cananea, Sonora, México, and flows to Arizona, USA, exemplifies this environmental issue.

Odor Removal Characteristics of a Laminated Film-Electrode Packed-Bed Nonthermal Plasma Reactor  [PDF]
Takuya Kuwahara,Masaaki Okubo,Tomoyuki Kuroki,Hideya Kametaka,Toshiaki Yamamoto
Sensors , 2011, DOI: 10.3390/s110605529
Abstract: Odor control has gained importance for ensuring a comfortable living environment. In this paper, the authors report the experimental results of a study on the detailed characteristics of a laminated film-electrode and a laminated film-electrode packed-bed nonthermal plasma reactor, which are types of dielectric barrier discharge (DBD) reactor used for odor control. These plasma reactors can be potentially used for the decomposition of volatile organic compounds (VOCs) and reduction of NOx. The reactor is driven by a low-cost 60-Hz neon transformer. Removal efficiencies under various experimental conditions are studied. The complete decomposition of the main odor component, namely, NH3, is achieved in a dry environment. The retention times are investigated for the complete removal of NH3 in the case of the film-electrode plasma reactor and the film-electrode packed-bed plasma reactor. The removal efficiency of the former reactor is lower than that of the latter reactor. Mixing another odor component such as CH3CHO in the gas stream has no significant effect on NH3 removal efficiency.
Drinking Water Denitrification in a Packed Bed Anoxic Reactor: Effect of Carbon Source and Reactor Depth  [PDF]
Saleh Faraj Magram
Journal of Applied Sciences , 2010,
Abstract: The main aim of this study was to investigate the effect of various carbon sources on the performance of anoxic upflow packed-bed reactor to remove nitrate from drinking water. The study further investigated the degree of removal of nitrate at different depths of reactors for determining the optimum depth. Nitrate contaminated groundwater is becoming a serious problem in many parts of the world. In view of the cost and toxic sludge production by the physico-chemical processes, biological treatment processes are preferable; however, the available studies have reported a wide range of denitrification performance depending on the carbon source and reactor type. In this study, the denitrification was the best in case of ethanol (average residual NO3 ˉ concentration of 15 mg L-1 with an influent concentration of around 200 mg L-1), while formic acid showed the worst performance. Denitrification performance in case of each carbon source varied depending on the depth of the reactor. Nevertheless, the fact that nitrate removal was achieved without encountering accumulation of nitrite makes the developed process very attractive.
Evaluation of Packed-Bed Reactor and Continuous Stirred Tank Reactor for the Production of Colchicine Derivatives  [PDF]
Kashyap Kumar Dubey,Dhirendra Kumar,Punit Kumar,Shafiul Haque,Arshad Jawed
ISRN Chemical Engineering , 2013, DOI: 10.1155/2013/865618
Abstract: Bioconversion of colchicine into its pharmacologically active derivative 3-demethylated colchicine (3-DMC) mediated by P450BM3 enzyme is an economic and promising strategy for the production of this inexpensive and potent anticancer drug. Continuous stirred tank reactor (CSTR) and packed-bed reactor (PBR) of 3?L and 2?L total volumes were compared for the production of 3-demethylated colchicine (3-DMC) a colchicine derivative using Bacillus megaterium MTCC*420 under aerobic conditions. Statistical optimization technique was utilized with the most significant variables, that is, dissolved oxygen (DO), colchicine concentration, and process time for optimization. The validation of the model was performed by experiments on the predicted values in an individual run, and the optimum parameters were DO (~50%), colchicine concentration (7.5?g/L), and process time (39?h) resulted in a maximum bioconversion of 3-DMC 3.36?g/L. The PBR reactor achieved much higher productivity (6.58?g/L/h) as reported by earlier researchers. This is the first report on the use of PBR for bioconversion of colchicine. 1. Introduction Bioreactor design is of crucial importance in the development of bioprocesses. Once a microorganism is selected and the culture and/or production conditions are optimized at laboratory scale, the next issue is proceeding to larger scale so that bulk quantities of the desired product can be produced optimally in a cost-effective manner. The selection of a proper reactor type is critical to such processes and plays a major role in large-scale production. The bioreactors widely used in today’s fermentation industry are mainly those developed in the past decades purely for chemical reactions [1, 2]. Among others, Stirred Tank Reactors (STRs) and Packed-Bed Reactors (PBRs) find the widest application. The application of these reactors for biological processes has been intensively studied with aerobic cultures [3–5]. Colchicine is a well-documented pseudo alkaloid obtained from Colchicum autumnale L. and Gloriosa superba, widely used in therapy for the treatment of gout pain persisting for a very long time [6, 7]. It is too toxic to be of value as an antitumor drug, in its native form. Derivatives of colchicine, that is, 3-demethylcolchicine, colchicoside, and thiocolchicoside with improved therapeutic properties for anti-inflammatory and anti-tumor drugs, have good commercial demand as these compounds are known to have clinical significance for the treatment of certain forms of leukemia and solid tumors [8, 9]. Colchicine and a number of its prepared
Continuous Production of Lipase-Catalyzed Biodiesel in a Packed-Bed Reactor: Optimization and Enzyme Reuse Study
Hsiao-Ching Chen,Hen-Yi Ju,Tsung-Ta Wu,Yung-Chuan Liu,Chih-Chen Lee,Cheng Chang,Yi-Lin Chung,Chwen-Jen Shieh
Journal of Biomedicine and Biotechnology , 2011, DOI: 10.1155/2011/950725
Abstract: An optimal continuous production of biodiesel by methanolysis of soybean oil in a packed-bed reactor was developed using immobilized lipase (Novozym 435) as a catalyst in a tert-butanol solvent system. Response surface methodology (RSM) and Box-Behnken design were employed to evaluate the effects of reaction temperature, flow rate, and substrate molar ratio on the molar conversion of biodiesel. The results showed that flow rate and temperature have significant effects on the percentage of molar conversion. On the basis of ridge max analysis, the optimum conditions were as follows: flow rate 0.1 mL/min, temperature 52.1°C, and substrate molar ratio 1 : 4. The predicted and experimental values of molar conversion were 83.31±2.07% and 82.81±.98%, respectively. Furthermore, the continuous process over 30 days showed no appreciable decrease in the molar conversion. The paper demonstrates the applicability of using immobilized lipase and a packed-bed reactor for continuous biodiesel synthesis.
Evaluation of a mechanistic mathematical model of a packed-bed anaerobic reactor treating wastewater
Sarti,A.; Foresti,E.; Zaiat,M.;
Latin American applied research , 2004,
Abstract: a mechanistic mathematical model is proposed and evaluated for simulating the performance of a bench-scale packed-bed anaerobic reactor that uses polyurethane foam as biomass support. the model developed under rational criteria was based on the study of mass transfer and biochemical kinetics, also considering the hydrodynamic characteristics of the reactor. the data generated by the model adhered well to the experimental data obtained from the operation of the reactor applied to the treatment of a glucosebased substrate. the liquid-phase mass transfer coefficient was found to be the main parameter in the model, and its precise estimation is essential for the model to be successfully applied. additionally, a case study was used in order to verify the applicability of the model for designing full-scale reactors. the simulations performed permitted to demonstrate the importance of the choice of convenient liquid superficial velocity and polyurethane foam matrix size which have direct influence on the solid- and liquid-phase mass transfers resistance and, consequently on the volume of the designed reactor.
Evaluation of a mechanistic mathematical model of a packed-bed anaerobic reactor treating wastewater
A. Sarti,E. Foresti,M. Zaiat
Latin American applied research , 2004,
Abstract: A mechanistic mathematical model is proposed and evaluated for simulating the performance of a bench-scale packed-bed anaerobic reactor that uses polyurethane foam as biomass support. The model developed under rational criteria was based on the study of mass transfer and biochemical kinetics, also considering the hydrodynamic characteristics of the reactor. The data generated by the model adhered well to the experimental data obtained from the operation of the reactor applied to the treatment of a glucosebased substrate. The liquid-phase mass transfer coefficient was found to be the main parameter in the model, and its precise estimation is essential for the model to be successfully applied. Additionally, a case study was used in order to verify the applicability of the model for designing full-scale reactors. The simulations performed permitted to demonstrate the importance of the choice of convenient liquid superficial velocity and polyurethane foam matrix size which have direct influence on the solid- and liquid-phase mass transfers resistance and, consequently on the volume of the designed reactor.
UPGRADING AN EXISTING WASTEWATER TREATMENT PLANT BASED ON AN UPFLOW ANAEROBIC PACKED-BED REACTOR
A. H. Mahvi,A. R. Mesdaghinia,R. Saeedi
Iranian Journal of Environmental Health Science & Engineering , 2007,
Abstract: The performance of an upflow anaerobic packed-bed reactor in the upgrading of Parkandabad (Mashhad, north east of Iran) wastewater treatment plant was studied in a pilot plant. The experiments were performed at hydraulic retention times of 6, 12, 18 and 24h based on empty reactor volume and the performance of the reactor was evaluated based on the removal of organic matter (BOD5 and COD) and SS. The average BOD5 and COD removal efficiencies were in the ranges of 79.0-89.3% and 75.7-87.2%, respectively, depending on HRT. The relationship between the organic loading rate and organic removal rate was linear in the loading range of 0.52-2.10kg BOD5/m3.d. The average SS removal efficiencies at hydraulic retention times of 6, 12, 18 and 24h were obtained to be 82.9, 83.6, 81.2 and 87.4%, respectively. The results indicated that the reactor in combination with existing biological treatment process (completely mixed aerated lagoon) can produce a high quality effluent.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.