Ammonium and nitrite are two substrates of anammox bacteria, but they are also inhibitors under high concentrations. The performance of two anaerobic ammonium-oxidizing (anammox) upflow biofilm (UBF) reactors was inve...Ammonium and nitrite are two substrates of anammox bacteria, but they are also inhibitors under high concentrations. The performance of two anaerobic ammonium-oxidizing (anammox) upflow biofilm (UBF) reactors was investigated. The results show that anammox UBFs become unstable under nitrogen loading rate (NLR) applied higher than 1.0 g/(L·d). The consumptions of acidity in the anammox reaction lead to the increase of pH, which is as high as 8.70-9.05. Free nitrous acid concentration is accompanied to be lower than the affinity constant of anammox bacteria, and then starvation effect appears. Moreover, free ammonia concentration increases to 57-178 mg/L, resulting in inhibitory effect on the anammox bacteria. Both negative effects contribute to the instability of the anammox bioreactors.展开更多
In this study,the effect of number of stages and bioreactor type on the removal performance of a sequential anaerobic-aerobic process employing activated sludge for the treatment of a simulated textile dyeing wastewat...In this study,the effect of number of stages and bioreactor type on the removal performance of a sequential anaerobic-aerobic process employing activated sludge for the treatment of a simulated textile dyeing wastewater containing three commercial reactive azo dyes was considered.Two stage processes performed better than one stage ones,both in terms of overall organic and color removal,as well as the higher contribution of anaerobic stage to the overall removal performance,thereby making them a more energy efficient option.The employment of a moving bed sequencing batch biofilm reactor,which uses both suspended and attached biomass,for the implementation of the anaerobic stage of the process,was compared with a sequencing batch reactor that only employs suspended biomass.The results showed that,although there was no meaningful difference in biomass concentration between the two bioreactors,the latter reactor had better performance in terms of chemical oxygen demand(COD)removal efficiency and rate and color removal rate.Further exploratory tests revealed a difference between the roles of suspended and attached bacterial populations,with the former yielding better color removal whilst the latter had better COD removal performance.The sequential anaerobic–aerobic process,employing an aerobic membrane bioreactor in the aerobic stage resulted in COD and color removal of 77.1±7.9%and 79.9±1.5%,respectively.The incomplete COD and color removal was attributed to the presence of soluble microbial products in the effluent and the autoxidation of dye reduction metabolites,respectively.Also,aerobic partial mineralization of the dye reduction metabolites,was experimentally observed.展开更多
Life on the earth is dependent on dynamic interactions between its physical, chemical and biological components. In fact, all the individual processes are responsible for regulating the environmental equilibrium which...Life on the earth is dependent on dynamic interactions between its physical, chemical and biological components. In fact, all the individual processes are responsible for regulating the environmental equilibrium which can provide biosphere for multiple forms of human life. In order to overcome on shortcomings, the use of immobilized cell bioreactor technology which provides a valuable effective for treatment of waste water is discussed. An immobilized system which in this matter is applied is about absorbed or captured microorganisms in a solid substratum to retain them in a reactor or analytical system. The multiply of these immobilized cells is done when by nutrients be supplied and then migrate to the surfaces which are referred to biofilms. The biofilms can be developed on various support systems such as polypropylene pall, rocks, sands, charcoal, ceramics, and glass beads. The controllable reaction vessels which are used for these colonized surfaces are referred to bioreactors. Bioreactors in both up flows and down flows mode which use of either batch or continuous processes principle can be operated. Synchronic with development in biotechnology, there is also an extensive development in the field of bioreactors like: pumped tower loop reactor (PTLR), liquid impelled loop reactor (LILR), multipurpose tower bioreactor (MTB), fluidized-bed and packed-bed bioreactor, that in this article are discussed them.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
The biodegradation performance of a novel photosynthetic bacterial biofilm reactor for hydrogen production using glucose as the sole carbon source during the start-up stage and steady operation stage was investigated ...The biodegradation performance of a novel photosynthetic bacterial biofilm reactor for hydrogen production using glucose as the sole carbon source during the start-up stage and steady operation stage was investigated experimentally.The effects of operation parameters,such as light intensity,light wave length,inlet substrate concentration,temperature and pH of the substrate medium on the biodegradation efficiency of the photosynthesis hydrogen production biofilm reactor were studied respectively.The experimental results showed that the glucose elimination capacity of the bioreactor increased rapidly in the biofilm formation stage,then fluctuated in the growth stage,and finally kept almost constant in the stabilization stage.The biodegradation efficiency of the photosynthesis hydrogen production biofilm reactor increased with the increase in light intensity,inlet substrate concentration,temperature and pH till the biodegradation efficiency reached a maximum value.Then the biodegradation efficiency decreased with the increase in these parameters.In addition,light wave length had significant influence on the biodegradation efficiency.展开更多
基金Project(2006AA06Z332) supported by the National High-Tech Research and Development Program of ChinaProject(30770039) supported by the National Natural Science Foundation of ChinaProject(2008BADC4B05) supported by the National Science and Technology Pillar Program
文摘Ammonium and nitrite are two substrates of anammox bacteria, but they are also inhibitors under high concentrations. The performance of two anaerobic ammonium-oxidizing (anammox) upflow biofilm (UBF) reactors was investigated. The results show that anammox UBFs become unstable under nitrogen loading rate (NLR) applied higher than 1.0 g/(L·d). The consumptions of acidity in the anammox reaction lead to the increase of pH, which is as high as 8.70-9.05. Free nitrous acid concentration is accompanied to be lower than the affinity constant of anammox bacteria, and then starvation effect appears. Moreover, free ammonia concentration increases to 57-178 mg/L, resulting in inhibitory effect on the anammox bacteria. Both negative effects contribute to the instability of the anammox bioreactors.
基金supported by Takmiliran textile dyeing factory(272219601)Materials and Energy Research Center(MERC)(99392003).
文摘In this study,the effect of number of stages and bioreactor type on the removal performance of a sequential anaerobic-aerobic process employing activated sludge for the treatment of a simulated textile dyeing wastewater containing three commercial reactive azo dyes was considered.Two stage processes performed better than one stage ones,both in terms of overall organic and color removal,as well as the higher contribution of anaerobic stage to the overall removal performance,thereby making them a more energy efficient option.The employment of a moving bed sequencing batch biofilm reactor,which uses both suspended and attached biomass,for the implementation of the anaerobic stage of the process,was compared with a sequencing batch reactor that only employs suspended biomass.The results showed that,although there was no meaningful difference in biomass concentration between the two bioreactors,the latter reactor had better performance in terms of chemical oxygen demand(COD)removal efficiency and rate and color removal rate.Further exploratory tests revealed a difference between the roles of suspended and attached bacterial populations,with the former yielding better color removal whilst the latter had better COD removal performance.The sequential anaerobic–aerobic process,employing an aerobic membrane bioreactor in the aerobic stage resulted in COD and color removal of 77.1±7.9%and 79.9±1.5%,respectively.The incomplete COD and color removal was attributed to the presence of soluble microbial products in the effluent and the autoxidation of dye reduction metabolites,respectively.Also,aerobic partial mineralization of the dye reduction metabolites,was experimentally observed.
文摘Life on the earth is dependent on dynamic interactions between its physical, chemical and biological components. In fact, all the individual processes are responsible for regulating the environmental equilibrium which can provide biosphere for multiple forms of human life. In order to overcome on shortcomings, the use of immobilized cell bioreactor technology which provides a valuable effective for treatment of waste water is discussed. An immobilized system which in this matter is applied is about absorbed or captured microorganisms in a solid substratum to retain them in a reactor or analytical system. The multiply of these immobilized cells is done when by nutrients be supplied and then migrate to the surfaces which are referred to biofilms. The biofilms can be developed on various support systems such as polypropylene pall, rocks, sands, charcoal, ceramics, and glass beads. The controllable reaction vessels which are used for these colonized surfaces are referred to bioreactors. Bioreactors in both up flows and down flows mode which use of either batch or continuous processes principle can be operated. Synchronic with development in biotechnology, there is also an extensive development in the field of bioreactors like: pumped tower loop reactor (PTLR), liquid impelled loop reactor (LILR), multipurpose tower bioreactor (MTB), fluidized-bed and packed-bed bioreactor, that in this article are discussed them.
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The biodegradation performance of a novel photosynthetic bacterial biofilm reactor for hydrogen production using glucose as the sole carbon source during the start-up stage and steady operation stage was investigated experimentally.The effects of operation parameters,such as light intensity,light wave length,inlet substrate concentration,temperature and pH of the substrate medium on the biodegradation efficiency of the photosynthesis hydrogen production biofilm reactor were studied respectively.The experimental results showed that the glucose elimination capacity of the bioreactor increased rapidly in the biofilm formation stage,then fluctuated in the growth stage,and finally kept almost constant in the stabilization stage.The biodegradation efficiency of the photosynthesis hydrogen production biofilm reactor increased with the increase in light intensity,inlet substrate concentration,temperature and pH till the biodegradation efficiency reached a maximum value.Then the biodegradation efficiency decreased with the increase in these parameters.In addition,light wave length had significant influence on the biodegradation efficiency.
