AIM: To construct and evaluate the functionality of a choanoid-fluidized bed bioreactor (CFBB) based on microencapsulated immortalized human hepatocytes.
From time immemorial, human beings have used pigments made from vegetables, fruits, superior plants, animal tissues and cereals. One of the greatest sources of pigments is the bacterium that, with the use of the moder...From time immemorial, human beings have used pigments made from vegetables, fruits, superior plants, animal tissues and cereals. One of the greatest sources of pigments is the bacterium that, with the use of the modern technology, has increased the production of metabolites of interest. The microbiological production of carotenoids has not been optimized to obtain pigment production quantities of pigments and carotenoids recovery that lower production costs. The aim of this work was to design a Zeaxanthin production process with Flavobacterium sp. immobilized cells in a fluidized bed bioreactor. An optimum culture medium for Zeaxanthin production in stirred flasks (2.46 g·L–1) was obtained. Furthermore, optimum process conditions for a maximum yield of Zeaxanthin production, by fluidized bed bioreactor, were established. A statistical analysis showed that the most significant factors were air flow, pH and NaCl concentration (4.5 g·L–1). In this study a maximum Zeaxanthin production of 3.8 g·L–1 was reached. The highest reported yield to date was 0.329 g·L–1.展开更多
The aim of this work was to investigate the aerobic degradation of high-strength industrial (refinery) wastewaters in the inverse fluidized bed biological reactor, in which polypropylene particles of density 910 kg/m3...The aim of this work was to investigate the aerobic degradation of high-strength industrial (refinery) wastewaters in the inverse fluidized bed biological reactor, in which polypropylene particles of density 910 kg/m3 were fluidized by an upward flow of gas through a bed. Measurements of chemical oxygen demand (COD) versus residence time t were performed for various ratios of settled bed volume to reactor volume (Vb/VR) and air velocities u. The largest COD reduction, namely, from 54,840 to 2,190 mg/l, i.e. a 96% COD decrease, was achieved when the reactor was operated at the ratio (Vb/VR) = 0.55, air velocity u = 0.046 m/s and t = 65 h. Thus, these values of (Vb/VR), u and t can be considered as the optimal operating parameters for a reactor when used in treatment of high-strength refinery wastewaters. In the treatment operation conducted in a reactor optimally controlled at (Vb/VR) = 0.55, u = 0.046 m/s and t = 65 h, the conversions obtained for all phenolic constituents of the wastewater were larger than 95%. The conversions of about 90% were attained for other hydrocarbons.展开更多
The aim of this work was the determination of the optimal aerations, and more specifically the corresponding optimal air velocities uopt, at which the largest COD removals were achieved in treatment of industrial wast...The aim of this work was the determination of the optimal aerations, and more specifically the corresponding optimal air velocities uopt, at which the largest COD removals were achieved in treatment of industrial wastewaters of various strength conducted in the inverse fluidized bed biofilm reactor. The largest COD removals were achieved at the following air velocities uopt and retention times ts, and (Vb/VR) = 0.55: i) for CODo = 72,780 mg/l at uopt = 0.052 m/s and ts = 80 h;ii) for CODo = 62,070 mg/l at uopt = 0.042 m/s and ts = 65 h;iii) for CODo = 49,130 mg/l at uopt = 0.033 m/s and ts= 55 h;iv) for CODo = 41,170 mg/l at uopt = 0.028 m/s and ts = 45 h;v) for CODo = 35,460 mg/l at uopt = 0.025 m/s and ts = 27.5 h;and vi) for CODo = 26,470 mg/l at uopt= 0.014 m/s and ts = 22.5 h. In the treatment operation conducted in a reactor optimally controlled at the above values of uopt, ts and (Vb/VR), the following decreases in COD were obtained: i) from 72,780 to 5410 mg/l;ii) from 62,070 to 3730 mg/l;iii) from 49,130 to 2820 mg/l;iv) from 41,170 to 1820 mg/l;v) from 35,460 to 1600 mg/l;and vi) from 26,470 to 1180 mg/l, that is, approximately a 93%, 94%, 95%, 96%, 95% and 96% COD reduction was attained, respectively.展开更多
A new bioreactor on the basis of a dynamic fluidized bed was designed, which combines advantages of the fluidized bed and a biological contactor. The experiments of start-up, nor- mal operation and parameter adjustmen...A new bioreactor on the basis of a dynamic fluidized bed was designed, which combines advantages of the fluidized bed and a biological contactor. The experiments of start-up, nor- mal operation and parameter adjustment are carried out. The re- sults show that the bioreactor can be quickly started up in the condition that the fill is 50%, the hydraulic retention time is 72 min, aerate speed is 2.5 m3/h, rotation-cage rotated speed is 1.5 r/min, and the removal rates of chemical oxygen demand (CODCr) and Ammonia nitrogen (NH3-N) are 75.34% and 80.98% respec- tively. The influence of the operation parameter on removal rates of the bioreactor is analyzed, and an appropriate operation pa- rameter is provided.展开更多
A continuous fluidized bed bioreactor （FBBR） with nylon support particles was used to treat synthetic sulfide wastewater at different hydraulic retention time of 25, 50 and 75 min and upflow velocity of 14, 17 and 2...A continuous fluidized bed bioreactor （FBBR） with nylon support particles was used to treat synthetic sulfide wastewater at different hydraulic retention time of 25, 50 and 75 min and upflow velocity of 14, 17 and 20 m/hr. The effects of upflow velocity, hydraulic retention time and reactor operation time on sulfide oxidation rate were studied using statistical model. Mixed culture obtained from the activated sludge, taken from tannery effluent treatment plant, was used as a source for microorganisms. The diameter and density of the nylon particles were 2-3 mm and 1140 kg/m3, respectively. Experiments were carried out in the reactor at a temperature of （30 ± 2）°C, at a fixed bed height of 16 cm after the formation of biofilm on the surface of support particles. Biofilm thickness reached （42 ± 3） μm after 15 days from reactor start-up. The sulfide oxidation, sulfate and sulfur formation is examined at all hydraulic retention times and upflow velocities. The results indicated that almost 90%-92% sulfide oxidation was achieved at all hydraulic retention times. Statistical model could explain 94% of the variability and analysis of variance showed that upflow velocity and hydraulic retention time slightly affected the sulfide oxidation rate. The highest sulfide oxidation of 92% with 70% sulfur was obtained at hydraulic retention time of 75 min and upflow velocity of 14 m/hr.展开更多
Choanoid fluidized bed bioreactors （CFBBs） are newly developed core devices used in bioartificial liver- support systems to detoxify blood plasma of patients with microencapsulated liver cells. Direct numerical simu...Choanoid fluidized bed bioreactors （CFBBs） are newly developed core devices used in bioartificial liver- support systems to detoxify blood plasma of patients with microencapsulated liver cells. Direct numerical simulations （DNS） with a direct-forcing/fictitious domain （DF/FD） method were conducted to study the hydrodynamic performance of a CFBB. The effects of particle-fluid density ratio, particle number, and fil- ter screens preventing particles flowing out of the reactor were investigated. Depending on density ratio, two flow patterns are evident： the circulation mode in which the suspension rises along one sidewall and descends along the other sidewall, and the non-circulation mode in which the whole suspension roughly flows upward. The circulation mode takes place under non-neutral-buoyancy where the particle sedimentation dominates, whereas the non-circulation mode occurs under pure or near-neutral buoy- ancy with particle-fluid density ratios of unity or near unity. With particle-fluid density ratio of 1.01, the bioartificial liver reactor performs optimally as the significant particle accumulation existing in the non-circulation mode and the large shear forces on particles in the circulation mode are avoided. At higher particle volume fractions, more particles accumulate at the filter screens and a secondary counter circulation to the primary flow is observed at the top of the bed. Modelled as porous media, the filter screens play a negative role on particle fluidization velocities; without screens, particles are fluidized faster because of the higher fluid velocities in the jet center region. This work extends the DF/FD-based DNS to a fluidized bed and accounts for effects from inclined side walls and porous media, providing some hydrodynamics insight that is important for CFBB design and operation optimization.展开更多
基金Supported by The Grants from the National Scientific and Technological Major Project of China,No.2011ZX10004-901,No.2013ZX10004904the National Science and Technology Major Project,No.2012ZX10002006
文摘AIM: To construct and evaluate the functionality of a choanoid-fluidized bed bioreactor (CFBB) based on microencapsulated immortalized human hepatocytes.
文摘From time immemorial, human beings have used pigments made from vegetables, fruits, superior plants, animal tissues and cereals. One of the greatest sources of pigments is the bacterium that, with the use of the modern technology, has increased the production of metabolites of interest. The microbiological production of carotenoids has not been optimized to obtain pigment production quantities of pigments and carotenoids recovery that lower production costs. The aim of this work was to design a Zeaxanthin production process with Flavobacterium sp. immobilized cells in a fluidized bed bioreactor. An optimum culture medium for Zeaxanthin production in stirred flasks (2.46 g·L–1) was obtained. Furthermore, optimum process conditions for a maximum yield of Zeaxanthin production, by fluidized bed bioreactor, were established. A statistical analysis showed that the most significant factors were air flow, pH and NaCl concentration (4.5 g·L–1). In this study a maximum Zeaxanthin production of 3.8 g·L–1 was reached. The highest reported yield to date was 0.329 g·L–1.
文摘The aim of this work was to investigate the aerobic degradation of high-strength industrial (refinery) wastewaters in the inverse fluidized bed biological reactor, in which polypropylene particles of density 910 kg/m3 were fluidized by an upward flow of gas through a bed. Measurements of chemical oxygen demand (COD) versus residence time t were performed for various ratios of settled bed volume to reactor volume (Vb/VR) and air velocities u. The largest COD reduction, namely, from 54,840 to 2,190 mg/l, i.e. a 96% COD decrease, was achieved when the reactor was operated at the ratio (Vb/VR) = 0.55, air velocity u = 0.046 m/s and t = 65 h. Thus, these values of (Vb/VR), u and t can be considered as the optimal operating parameters for a reactor when used in treatment of high-strength refinery wastewaters. In the treatment operation conducted in a reactor optimally controlled at (Vb/VR) = 0.55, u = 0.046 m/s and t = 65 h, the conversions obtained for all phenolic constituents of the wastewater were larger than 95%. The conversions of about 90% were attained for other hydrocarbons.
文摘The aim of this work was the determination of the optimal aerations, and more specifically the corresponding optimal air velocities uopt, at which the largest COD removals were achieved in treatment of industrial wastewaters of various strength conducted in the inverse fluidized bed biofilm reactor. The largest COD removals were achieved at the following air velocities uopt and retention times ts, and (Vb/VR) = 0.55: i) for CODo = 72,780 mg/l at uopt = 0.052 m/s and ts = 80 h;ii) for CODo = 62,070 mg/l at uopt = 0.042 m/s and ts = 65 h;iii) for CODo = 49,130 mg/l at uopt = 0.033 m/s and ts= 55 h;iv) for CODo = 41,170 mg/l at uopt = 0.028 m/s and ts = 45 h;v) for CODo = 35,460 mg/l at uopt = 0.025 m/s and ts = 27.5 h;and vi) for CODo = 26,470 mg/l at uopt= 0.014 m/s and ts = 22.5 h. In the treatment operation conducted in a reactor optimally controlled at the above values of uopt, ts and (Vb/VR), the following decreases in COD were obtained: i) from 72,780 to 5410 mg/l;ii) from 62,070 to 3730 mg/l;iii) from 49,130 to 2820 mg/l;iv) from 41,170 to 1820 mg/l;v) from 35,460 to 1600 mg/l;and vi) from 26,470 to 1180 mg/l, that is, approximately a 93%, 94%, 95%, 96%, 95% and 96% COD reduction was attained, respectively.
文摘A new bioreactor on the basis of a dynamic fluidized bed was designed, which combines advantages of the fluidized bed and a biological contactor. The experiments of start-up, nor- mal operation and parameter adjustment are carried out. The re- sults show that the bioreactor can be quickly started up in the condition that the fill is 50%, the hydraulic retention time is 72 min, aerate speed is 2.5 m3/h, rotation-cage rotated speed is 1.5 r/min, and the removal rates of chemical oxygen demand (CODCr) and Ammonia nitrogen (NH3-N) are 75.34% and 80.98% respec- tively. The influence of the operation parameter on removal rates of the bioreactor is analyzed, and an appropriate operation pa- rameter is provided.
文摘A continuous fluidized bed bioreactor （FBBR） with nylon support particles was used to treat synthetic sulfide wastewater at different hydraulic retention time of 25, 50 and 75 min and upflow velocity of 14, 17 and 20 m/hr. The effects of upflow velocity, hydraulic retention time and reactor operation time on sulfide oxidation rate were studied using statistical model. Mixed culture obtained from the activated sludge, taken from tannery effluent treatment plant, was used as a source for microorganisms. The diameter and density of the nylon particles were 2-3 mm and 1140 kg/m3, respectively. Experiments were carried out in the reactor at a temperature of （30 ± 2）°C, at a fixed bed height of 16 cm after the formation of biofilm on the surface of support particles. Biofilm thickness reached （42 ± 3） μm after 15 days from reactor start-up. The sulfide oxidation, sulfate and sulfur formation is examined at all hydraulic retention times and upflow velocities. The results indicated that almost 90%-92% sulfide oxidation was achieved at all hydraulic retention times. Statistical model could explain 94% of the variability and analysis of variance showed that upflow velocity and hydraulic retention time slightly affected the sulfide oxidation rate. The highest sulfide oxidation of 92% with 70% sulfur was obtained at hydraulic retention time of 75 min and upflow velocity of 14 m/hr.
基金The authors gratefully acknowledge the supports from China Postdoctoral Science Foundation （Grant No. 2014M550327）, the opening foundation of the State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, and the National Natural Science Foundation of China （Grant No. 11372275）. The authors are also grateful to Chengbo Yu and Liang Yu for their introduction of the choanoid fluidized bed bioreactor and helpful discussions.
文摘Choanoid fluidized bed bioreactors （CFBBs） are newly developed core devices used in bioartificial liver- support systems to detoxify blood plasma of patients with microencapsulated liver cells. Direct numerical simulations （DNS） with a direct-forcing/fictitious domain （DF/FD） method were conducted to study the hydrodynamic performance of a CFBB. The effects of particle-fluid density ratio, particle number, and fil- ter screens preventing particles flowing out of the reactor were investigated. Depending on density ratio, two flow patterns are evident： the circulation mode in which the suspension rises along one sidewall and descends along the other sidewall, and the non-circulation mode in which the whole suspension roughly flows upward. The circulation mode takes place under non-neutral-buoyancy where the particle sedimentation dominates, whereas the non-circulation mode occurs under pure or near-neutral buoy- ancy with particle-fluid density ratios of unity or near unity. With particle-fluid density ratio of 1.01, the bioartificial liver reactor performs optimally as the significant particle accumulation existing in the non-circulation mode and the large shear forces on particles in the circulation mode are avoided. At higher particle volume fractions, more particles accumulate at the filter screens and a secondary counter circulation to the primary flow is observed at the top of the bed. Modelled as porous media, the filter screens play a negative role on particle fluidization velocities; without screens, particles are fluidized faster because of the higher fluid velocities in the jet center region. This work extends the DF/FD-based DNS to a fluidized bed and accounts for effects from inclined side walls and porous media, providing some hydrodynamics insight that is important for CFBB design and operation optimization.
