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J M Poyatos - One of the best experts on this subject based on the ideXlab platform.
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influence of sludge retention time and temperature on the sludge removal in a submerged membrane bioreactor comparative study between pure oxygen and air to supply Aerobic Conditions
Journal of Environmental Science and Health Part A-toxic\ hazardous Substances & Environmental Engineering, 2014Co-Authors: F A Rodriguez, Juan Carlos Leyvadiaz, Patricia Reboleirorivas, J Gonzalezlopez, E Hontoria, J M PoyatosAbstract:Performance of a bench-scale wastewater treatment plant, which consisted of a membrane bioreactor, was monitored daily using pure oxygen and air to supply Aerobic Conditions with the aim of studying the increases of the aeration and sludge removal efficiencies and the effect of the temperature. The results showed the capacity of membrane bioreactor systems for removing organic matter. The alpha-factors of the aeration were determined for six different MLSS concentrations in order to understand the system working when pure oxygen and air were used to supply Aerobic Conditions in the system. Aeration efficiency was increased between 30.7 and 45.9% when pure oxygen was used in the operation Conditions (a hydraulic retention time of 12 h and MLSS concentrations between 4,018 and 11,192 mg/L). Sludge removal efficiency increased incrementally, from 0.2 to 1.5% when pure oxygen was used at low sludge retention time and from 1.5% to 15.4% at medium sludge retention time when temperature Conditions were lower tha...
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influence of mixed liquid suspended solids and hydraulic retention time on oxygen transfer efficiency and viscosity in a submerged membrane bioreactor using pure oxygen to supply Aerobic Conditions
Biochemical Engineering Journal, 2012Co-Authors: F A Rodriguez, Patricia Reboleirorivas, E Hontoria, Francisco Osorio, M V Martineztoledo, J M PoyatosAbstract:Abstract The performance of a wastewater bench-scale membrane bioreactor (MBR) treatment plant using pure oxygen Conditions was monitored daily to provide Aerobic Conditions. The results showed the capacity of the MBR system to remove organic material over at hydraulic retention time (HRT) of 12 h and 18 h. The alpha-factors of aeration were determined at three different mixed liquid suspended solids (MLSS) concentrations, in order to understand the system performance when pure oxygen was used to provide the Aerobic Conditions of the MBR system. Under these working Conditions, an alpha-factor in the range 0.90–0.12 was obtained when the HRT of 18 h was performed, and the MLSS concentration increased from 4300 to 10,275 mg/L. Additionally, an alpha-factor in the range of 0.28–0.02 was obtained at HRT of 12 h and the MLSS increased from 4071 to 11,192 mg/L. Our study suggested significant changes in the behaviour of the biological system (viscosity, aeration efficiency, organic matter removal) when the concentration of MLSS was increased and the HRT decreased in the bioreactor, decreasing the aeration efficiency in both cases. Furthermore, the efficiency of aeration seems to be more affected by MLSS concentration than by HRT under our operating Conditions over the range studied.
P. Xu - One of the best experts on this subject based on the ideXlab platform.
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Microbial fed-batch production of 1,3-propanediol by Klebsiella pneumoniae under micro-Aerobic Conditions
Applied Microbiology and Biotechnology, 2003Co-Authors: X. Chen, W. T. Qi, Z. L. Xiu, S. J. Gao, D.-j. Zhang, P. XuAbstract:The microbial production of 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae under micro-Aerobic Conditions was investigated in this study. The experimental results of batch fermentation showed that the final concentration and yield of 1,3-PD on glycerol under micro-Aerobic Conditions approached values achieved under anAerobic Conditions. However, less ethanol was produced under microAerobic than anAerobic Conditions at the end of fermentation. The batch micro-Aerobic fermentation time was markedly shorter than that of anAerobic fermentation. This led to an increment of productivity of 1,3-PD. For instance, the concentration, molar yield, and productivity of 1,3-PD of batch micro-Aerobic fermentation by K. pneumoniae DSM 2026 were 17.65 g/l, 56.13%, and 2.94 g l(-1) h(-1), respectively, with a fermentation time of 6 h and an initial glycerol concentration of 40 g/l. Compared with DSM 2026, the microbial growth of K. pneumoniae AS 1.1736 was slow and the concentration of 1,3-PD was low under the same Conditions. Furthermore, the microbial growth in fed-batch fermentation by K. pneumoniae DSM 2026 was faster under micro-Aerobic than anAerobic Conditions. The concentration, molar yield, and productivity of 1,3-PD in fed-batch fermentation under micro-Aerobic Conditions were 59.50 g/l, 51.75%, and 1.57 g l(-1) h(-1), respectively. The volumetric productivity of 1,3-PD under microAerobic Conditions was almost twice that of anAerobic fed-batch fermentation, at 1.57 and 0.80 g l(-1) h(-1), respectively.
Dongzhi Wei - One of the best experts on this subject based on the ideXlab platform.
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effects of over expression of glycerol dehydrogenase and 1 3 propanediol oxidoreductase on bioconversion of glycerol into 1 3 propandediol by klebsiella pneumoniae under micro Aerobic Conditions
Bioprocess and Biosystems Engineering, 2009Co-Authors: Li Zhao, Yu Zheng, Dongzhi WeiAbstract:Glycerol dehydrogenase (GDH) and 1,3-propanediol (1,3-PD) oxidoreductase had been proved two key enzymes for 1,3-PD production by Klebsiella pneumoniae. Fed-batch fermentations of the recombinant K. pneumoniae strains, over-expressing the two enzymes individually, were carried out under micro-Aerobic Conditions, and the behaviors of the recombinants were investigated. Results showed that over-expression of 1,3-PD oxidoreductase did not affect the concentration of 1,3-PD. However, it enhanced the molar yield from 50.6 to 64.0% and reduced the concentration of by-products. Among them, the concentrations of lactic acid, ethanol and succinic acid were decreased by 51.8, 50.6 and 47.4%, respectively. Moreover, in the recombinant the maximal concentration of 3-hydroxypropionaldehyde decreased by 73.6%. Over-expression of GDH decreased the yield of ethanol and 2,3-butanediol, meanwhile it increased the concentration of acetic acid. No significant changes were observed both in 1,3-PD yield and glycerol flux distributed to oxidative branch.
F A Rodriguez - One of the best experts on this subject based on the ideXlab platform.
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influence of sludge retention time and temperature on the sludge removal in a submerged membrane bioreactor comparative study between pure oxygen and air to supply Aerobic Conditions
Journal of Environmental Science and Health Part A-toxic\ hazardous Substances & Environmental Engineering, 2014Co-Authors: F A Rodriguez, Juan Carlos Leyvadiaz, Patricia Reboleirorivas, J Gonzalezlopez, E Hontoria, J M PoyatosAbstract:Performance of a bench-scale wastewater treatment plant, which consisted of a membrane bioreactor, was monitored daily using pure oxygen and air to supply Aerobic Conditions with the aim of studying the increases of the aeration and sludge removal efficiencies and the effect of the temperature. The results showed the capacity of membrane bioreactor systems for removing organic matter. The alpha-factors of the aeration were determined for six different MLSS concentrations in order to understand the system working when pure oxygen and air were used to supply Aerobic Conditions in the system. Aeration efficiency was increased between 30.7 and 45.9% when pure oxygen was used in the operation Conditions (a hydraulic retention time of 12 h and MLSS concentrations between 4,018 and 11,192 mg/L). Sludge removal efficiency increased incrementally, from 0.2 to 1.5% when pure oxygen was used at low sludge retention time and from 1.5% to 15.4% at medium sludge retention time when temperature Conditions were lower tha...
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influence of mixed liquid suspended solids and hydraulic retention time on oxygen transfer efficiency and viscosity in a submerged membrane bioreactor using pure oxygen to supply Aerobic Conditions
Biochemical Engineering Journal, 2012Co-Authors: F A Rodriguez, Patricia Reboleirorivas, E Hontoria, Francisco Osorio, M V Martineztoledo, J M PoyatosAbstract:Abstract The performance of a wastewater bench-scale membrane bioreactor (MBR) treatment plant using pure oxygen Conditions was monitored daily to provide Aerobic Conditions. The results showed the capacity of the MBR system to remove organic material over at hydraulic retention time (HRT) of 12 h and 18 h. The alpha-factors of aeration were determined at three different mixed liquid suspended solids (MLSS) concentrations, in order to understand the system performance when pure oxygen was used to provide the Aerobic Conditions of the MBR system. Under these working Conditions, an alpha-factor in the range 0.90–0.12 was obtained when the HRT of 18 h was performed, and the MLSS concentration increased from 4300 to 10,275 mg/L. Additionally, an alpha-factor in the range of 0.28–0.02 was obtained at HRT of 12 h and the MLSS increased from 4071 to 11,192 mg/L. Our study suggested significant changes in the behaviour of the biological system (viscosity, aeration efficiency, organic matter removal) when the concentration of MLSS was increased and the HRT decreased in the bioreactor, decreasing the aeration efficiency in both cases. Furthermore, the efficiency of aeration seems to be more affected by MLSS concentration than by HRT under our operating Conditions over the range studied.
X. Chen - One of the best experts on this subject based on the ideXlab platform.
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Microbial fed-batch production of 1,3-propanediol by Klebsiella pneumoniae under micro-Aerobic Conditions
Applied Microbiology and Biotechnology, 2003Co-Authors: X. Chen, W. T. Qi, Z. L. Xiu, S. J. Gao, D.-j. Zhang, P. XuAbstract:The microbial production of 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae under micro-Aerobic Conditions was investigated in this study. The experimental results of batch fermentation showed that the final concentration and yield of 1,3-PD on glycerol under micro-Aerobic Conditions approached values achieved under anAerobic Conditions. However, less ethanol was produced under microAerobic than anAerobic Conditions at the end of fermentation. The batch micro-Aerobic fermentation time was markedly shorter than that of anAerobic fermentation. This led to an increment of productivity of 1,3-PD. For instance, the concentration, molar yield, and productivity of 1,3-PD of batch micro-Aerobic fermentation by K. pneumoniae DSM 2026 were 17.65 g/l, 56.13%, and 2.94 g l(-1) h(-1), respectively, with a fermentation time of 6 h and an initial glycerol concentration of 40 g/l. Compared with DSM 2026, the microbial growth of K. pneumoniae AS 1.1736 was slow and the concentration of 1,3-PD was low under the same Conditions. Furthermore, the microbial growth in fed-batch fermentation by K. pneumoniae DSM 2026 was faster under micro-Aerobic than anAerobic Conditions. The concentration, molar yield, and productivity of 1,3-PD in fed-batch fermentation under micro-Aerobic Conditions were 59.50 g/l, 51.75%, and 1.57 g l(-1) h(-1), respectively. The volumetric productivity of 1,3-PD under microAerobic Conditions was almost twice that of anAerobic fed-batch fermentation, at 1.57 and 0.80 g l(-1) h(-1), respectively.