Anaerobic expanded bed reactor(AEBR) is mostly used for the treatment of fairly low strength wastewaters. Since the performance of AEBR largely depends on its hydraulic characteristics, residence time distribution(RTD...Anaerobic expanded bed reactor(AEBR) is mostly used for the treatment of fairly low strength wastewaters. Since the performance of AEBR largely depends on its hydraulic characteristics, residence time distribution(RTD) method is commonly used for investigation of the hydraulic characteristics of AEBR under different ascending velocity of mixed liquor. In this paper, a pilot-scale AEBR reactor is investigated for treatment of municipal sewage in which lithium chloride is used as a tracer. The results show that the AEBR could be considered as the superimposition of several constant stirred tank reactors(CSTR) and the increase of hydraulic up-flow velocity could increase the number of the CSTR and decrease the volume rate of the dead zone. The optimal up-flow velocity of the investigated AEBR was approximately 1.9 m/h in the municipal sewage treatment.展开更多
Activated carbon(AC) was prepared from surplus sludge using chemical activation method with the assistance of ZnCl2. The influences of process parameters on the AC's specific surface area and adsorption capacity f...Activated carbon(AC) was prepared from surplus sludge using chemical activation method with the assistance of ZnCl2. The influences of process parameters on the AC's specific surface area and adsorption capacity for Pb2+ were examined to optimize these parameters. The optimal conditions for the preparation of AC were determined to be activation temperature of 500 °C, activation time of 1 h, impregnation ratio of 1:1(solid-to-liquid volume) with the 30% ZnCl2 solution(mass fraction), giving the BET surface area of 393.85 m2/g and yield of 30.14% with 33.45% ash. Also, the pyrolysis temperature was found to be the most important parameter in chemical activation. FTIR spectra provided the evidence of some surface structures such as C=C and C—O—C. In the adsorption studies, a rise in solution pH led to a significant increase in adsorption capacity when the pH value varied from 3.0 to 7.0, and the optimal pH for removal of Pb2+ was 7.0. It was observed that the pseudo-second-order equation provided better correlation for the adsorption rate than the pseudo-first-order and the Langmuir model fitted better than the Freundlich model for adsorption isotherm. The adsorption capacity of AC to Pb2+ was 11.75 mg/L at solution pH 7.0, the equilibrium time 480 min and 25 °C. Moreover, the adsorption process is endothermic according to the value of enthalpy change.展开更多
文摘Anaerobic expanded bed reactor(AEBR) is mostly used for the treatment of fairly low strength wastewaters. Since the performance of AEBR largely depends on its hydraulic characteristics, residence time distribution(RTD) method is commonly used for investigation of the hydraulic characteristics of AEBR under different ascending velocity of mixed liquor. In this paper, a pilot-scale AEBR reactor is investigated for treatment of municipal sewage in which lithium chloride is used as a tracer. The results show that the AEBR could be considered as the superimposition of several constant stirred tank reactors(CSTR) and the increase of hydraulic up-flow velocity could increase the number of the CSTR and decrease the volume rate of the dead zone. The optimal up-flow velocity of the investigated AEBR was approximately 1.9 m/h in the municipal sewage treatment.
基金Project supported by the Open Fund of State Key Laboratory of Photocatalysis,China
文摘Activated carbon(AC) was prepared from surplus sludge using chemical activation method with the assistance of ZnCl2. The influences of process parameters on the AC's specific surface area and adsorption capacity for Pb2+ were examined to optimize these parameters. The optimal conditions for the preparation of AC were determined to be activation temperature of 500 °C, activation time of 1 h, impregnation ratio of 1:1(solid-to-liquid volume) with the 30% ZnCl2 solution(mass fraction), giving the BET surface area of 393.85 m2/g and yield of 30.14% with 33.45% ash. Also, the pyrolysis temperature was found to be the most important parameter in chemical activation. FTIR spectra provided the evidence of some surface structures such as C=C and C—O—C. In the adsorption studies, a rise in solution pH led to a significant increase in adsorption capacity when the pH value varied from 3.0 to 7.0, and the optimal pH for removal of Pb2+ was 7.0. It was observed that the pseudo-second-order equation provided better correlation for the adsorption rate than the pseudo-first-order and the Langmuir model fitted better than the Freundlich model for adsorption isotherm. The adsorption capacity of AC to Pb2+ was 11.75 mg/L at solution pH 7.0, the equilibrium time 480 min and 25 °C. Moreover, the adsorption process is endothermic according to the value of enthalpy change.
