Due to a prolonged operation time and low mass transfer efficiency, the primary challenge in the aeration process of non-Newtonian fluids is the high energy consumption, which is closely related to the form and rate o...Due to a prolonged operation time and low mass transfer efficiency, the primary challenge in the aeration process of non-Newtonian fluids is the high energy consumption, which is closely related to the form and rate of impeller, ventilation, rheological properties and bubble morphology in the reactor. In this perspective, through optimal computational fluid dynamics models and experiments, the relationship between power consumption, volumetric mass transfer rate(kLa) and initial bubble size(d0) was constructed to establish an efficient operation mode for the aeration process of non-Newtonian fluids. It was found that reducing the d0could significantly increase the oxygen mass transfer rate, resulting in an obvious decrease in the ventilation volume and impeller speed. When d0was regulated within 2-5 mm,an optimal kLa could be achieved, and 21% of power consumption could be saved, compared to the case of bubbles with a diameter of 10 mm.展开更多
A practice wastewater treatment plant was operated using intermittent aeration activated sludge process to enhance biological nitrogen and phosphorus removal. When the influent concentrations of COD Cr , BOD 5, T...A practice wastewater treatment plant was operated using intermittent aeration activated sludge process to enhance biological nitrogen and phosphorus removal. When the influent concentrations of COD Cr , BOD 5, TN, TP, NH 3\|N, TKN, and SS varied in a range of 207.5—1640 mg/L, 61.8—637 mg/L, 28.5—75.6 mg/L, 4.38—20.2 mg/L, 13.6—31.9 mg/L, 28.5—75.6 mg/L, and 111—1208 mg/L, the effluent means were less than 50 mg/L, 20 mg/L, 5 mg/L, 1.0 mg/L, 5 mg/L, 10 mg/L, and 20 mg/L, respectively. Based on a long time of operating results, this process is very suitable for nutrient biological removal for treating the municipal wastewater those water characteristics are similar as that of the Songjiang Municipal Waste Water Treatment Plant(SJMWTP).展开更多
Water quality determines the success of inland aquaculture.The factor determining water quality is the concentration of dissolved oxygen(DO).To find effective paddlewheel aerators to enhance DO concentration,nine mode...Water quality determines the success of inland aquaculture.The factor determining water quality is the concentration of dissolved oxygen(DO).To find effective paddlewheel aerators to enhance DO concentration,nine model aerators were examined:aerator 4 blades,6 blades and 8 blades with variations of 12 holes per blade,16 holes per blade and 20 holes per blade.They were rotated at 80 RPM,100 RPM,120 RPM and 140 RPM.The results show the higher the rotation speed is,the bigger the increment of DO concentration is,but their relationship is not linier.There is a condition when increasing rotation does not affect the DO concentration meaningly.The results also indicate the greater number of blades increase more DO concentration.The results also suggest the greater number of holes per blade initially increase DO concentration increment,but after 16 holes the increment tends to reduce.It is predicted owing to that widening surface interaction due to the holes in the blade is taken over by reducing the volume of splashed water.In this research,likely the aerator with 8 blades,16 holes per blade and rotated at 120 RPM is the optimum one to increase DO concentration.However,if the energy consumption is also the concern,the aerator with 6 blades and 16 holes per blade likely is the better choice.展开更多
基金financial support of the National Natural Science Foundation of China(21776122).
文摘Due to a prolonged operation time and low mass transfer efficiency, the primary challenge in the aeration process of non-Newtonian fluids is the high energy consumption, which is closely related to the form and rate of impeller, ventilation, rheological properties and bubble morphology in the reactor. In this perspective, through optimal computational fluid dynamics models and experiments, the relationship between power consumption, volumetric mass transfer rate(kLa) and initial bubble size(d0) was constructed to establish an efficient operation mode for the aeration process of non-Newtonian fluids. It was found that reducing the d0could significantly increase the oxygen mass transfer rate, resulting in an obvious decrease in the ventilation volume and impeller speed. When d0was regulated within 2-5 mm,an optimal kLa could be achieved, and 21% of power consumption could be saved, compared to the case of bubbles with a diameter of 10 mm.
文摘A practice wastewater treatment plant was operated using intermittent aeration activated sludge process to enhance biological nitrogen and phosphorus removal. When the influent concentrations of COD Cr , BOD 5, TN, TP, NH 3\|N, TKN, and SS varied in a range of 207.5—1640 mg/L, 61.8—637 mg/L, 28.5—75.6 mg/L, 4.38—20.2 mg/L, 13.6—31.9 mg/L, 28.5—75.6 mg/L, and 111—1208 mg/L, the effluent means were less than 50 mg/L, 20 mg/L, 5 mg/L, 1.0 mg/L, 5 mg/L, 10 mg/L, and 20 mg/L, respectively. Based on a long time of operating results, this process is very suitable for nutrient biological removal for treating the municipal wastewater those water characteristics are similar as that of the Songjiang Municipal Waste Water Treatment Plant(SJMWTP).
基金the Ministry of Education and Culture,Research and Technology,Higher Education of the Republic of Indonesia(grant number 069/E5/PG.02.00.PT/2022).
文摘Water quality determines the success of inland aquaculture.The factor determining water quality is the concentration of dissolved oxygen(DO).To find effective paddlewheel aerators to enhance DO concentration,nine model aerators were examined:aerator 4 blades,6 blades and 8 blades with variations of 12 holes per blade,16 holes per blade and 20 holes per blade.They were rotated at 80 RPM,100 RPM,120 RPM and 140 RPM.The results show the higher the rotation speed is,the bigger the increment of DO concentration is,but their relationship is not linier.There is a condition when increasing rotation does not affect the DO concentration meaningly.The results also indicate the greater number of blades increase more DO concentration.The results also suggest the greater number of holes per blade initially increase DO concentration increment,but after 16 holes the increment tends to reduce.It is predicted owing to that widening surface interaction due to the holes in the blade is taken over by reducing the volume of splashed water.In this research,likely the aerator with 8 blades,16 holes per blade and rotated at 120 RPM is the optimum one to increase DO concentration.However,if the energy consumption is also the concern,the aerator with 6 blades and 16 holes per blade likely is the better choice.
