CO2 removal from biogas by water washing system was investigated with various parameters, including liquid/ gas ratio, pressure, temperature, and CO2 content. The results indicate that CO2 removal ratio could reach 34...CO2 removal from biogas by water washing system was investigated with various parameters, including liquid/ gas ratio, pressure, temperature, and CO2 content. The results indicate that CO2 removal ratio could reach 34.6%- 94.2% as liquid/gas ratio increased from 0.14 to 0.50. Increasing pressure （from 0.8 to 1.2 MPa） could improve gas purification with a constant inflow rate of gas. Temperature played a key role in the process and lower temper- ature in absorption tower was beneficial for reducing CO2 content. CO2 removal ratio could reach 24.4%-83.2% when CO2 content in the simulated gas was 25%-45%. The lowest CO2 content after absorption was 2.6% at 1.2 MPa with 400 L·h-1 gas flow and 200 L·h-1 water flow, which meets the requirement of CO2 content in natural Ras for vehicle fuel.展开更多
Membrane fouling is the main problem of membrane bioreactors (MBR), which seriously influ- ences its wastewater treatment effect and running. The characteristics of microbiology and hydrodynamics concerning membrane f...Membrane fouling is the main problem of membrane bioreactors (MBR), which seriously influ- ences its wastewater treatment effect and running. The characteristics of microbiology and hydrodynamics concerning membrane fouling were investigated and the measure was put forward for optimum operation of MBR. The measure is that 1) the parameters of activated sludge concentration (X) and membrane flux should be lower than the critical values of X and membrane flux respectively, and 2) the activated sludge should be discharged periodically. The experimental results show that the combination backwashing of gas and perme- ated effluent is better than single gas backwashing or single permeated effluent backwashing. This technique can remove the cake layer deposited on the membrane surface, decrease the membrane fouling, and recover the membrane flux effectively. So it is effective for prevention of membrane fouling.展开更多
Biological aerated filter （BAF） is an advanced oxidation process that can sustain high volumetric loads with high quality effluent. However, backwashing process needed for the system limits its applicability. This s...Biological aerated filter （BAF） is an advanced oxidation process that can sustain high volumetric loads with high quality effluent. However, backwashing process needed for the system limits its applicability. This study is to investigate the possibility of removing carbon and nitrogen simultaneously in a biological aerated filter （BAF） with partially packed media without any backwashing process. The upper part of BAF up to 0.5 m depth is packed with plastic media （Kaldnes K1） with diameter and length of 10 mm and 7 mm respectively. This partially packed BAF creates a hybrid system of attached growth and suspended growth combined in a single reactor. Three C：N ratios, i.e. 15, 10 and 4, were compared during this study by varying the nitrogen loading while the carbon loading was kept constant at 1.0±0.54 kg COD/（m^3·d）. The organic loading rate （OLR） ratios were calculated based on carbon and TKN loading. The carbon removal percentage of 86.7±7.3%, 85.1±10.3%, and 91.0±5.6% and TKN removal percentage of 24.7±11.6%, 48.0±25.9% and 62.8±7.9% were achieved after steady-state for the C：N ratio of 15, 10, and 4 respectively. Suspended solid concentration in the effluent was found to be high throughout the treatment, but no clogging occurred during the 4 months of operation period even though backwashing was eliminated.展开更多
基金Supported by the National Technology Research and Development Program of China(2008AA062402)the China-US International Cooperation Project(2011DFA90800)the Ministry of Science and Technology,China
文摘CO2 removal from biogas by water washing system was investigated with various parameters, including liquid/ gas ratio, pressure, temperature, and CO2 content. The results indicate that CO2 removal ratio could reach 34.6%- 94.2% as liquid/gas ratio increased from 0.14 to 0.50. Increasing pressure （from 0.8 to 1.2 MPa） could improve gas purification with a constant inflow rate of gas. Temperature played a key role in the process and lower temper- ature in absorption tower was beneficial for reducing CO2 content. CO2 removal ratio could reach 24.4%-83.2% when CO2 content in the simulated gas was 25%-45%. The lowest CO2 content after absorption was 2.6% at 1.2 MPa with 400 L·h-1 gas flow and 200 L·h-1 water flow, which meets the requirement of CO2 content in natural Ras for vehicle fuel.
文摘Membrane fouling is the main problem of membrane bioreactors (MBR), which seriously influ- ences its wastewater treatment effect and running. The characteristics of microbiology and hydrodynamics concerning membrane fouling were investigated and the measure was put forward for optimum operation of MBR. The measure is that 1) the parameters of activated sludge concentration (X) and membrane flux should be lower than the critical values of X and membrane flux respectively, and 2) the activated sludge should be discharged periodically. The experimental results show that the combination backwashing of gas and perme- ated effluent is better than single gas backwashing or single permeated effluent backwashing. This technique can remove the cake layer deposited on the membrane surface, decrease the membrane fouling, and recover the membrane flux effectively. So it is effective for prevention of membrane fouling.
文摘Biological aerated filter （BAF） is an advanced oxidation process that can sustain high volumetric loads with high quality effluent. However, backwashing process needed for the system limits its applicability. This study is to investigate the possibility of removing carbon and nitrogen simultaneously in a biological aerated filter （BAF） with partially packed media without any backwashing process. The upper part of BAF up to 0.5 m depth is packed with plastic media （Kaldnes K1） with diameter and length of 10 mm and 7 mm respectively. This partially packed BAF creates a hybrid system of attached growth and suspended growth combined in a single reactor. Three C：N ratios, i.e. 15, 10 and 4, were compared during this study by varying the nitrogen loading while the carbon loading was kept constant at 1.0±0.54 kg COD/（m^3·d）. The organic loading rate （OLR） ratios were calculated based on carbon and TKN loading. The carbon removal percentage of 86.7±7.3%, 85.1±10.3%, and 91.0±5.6% and TKN removal percentage of 24.7±11.6%, 48.0±25.9% and 62.8±7.9% were achieved after steady-state for the C：N ratio of 15, 10, and 4 respectively. Suspended solid concentration in the effluent was found to be high throughout the treatment, but no clogging occurred during the 4 months of operation period even though backwashing was eliminated.
