The paper establishes the relationship between the settling efficiency and the sizes of the sedimentation tank through the process of numerical simulation, which is taken as one of the constraints to set up a simple o...The paper establishes the relationship between the settling efficiency and the sizes of the sedimentation tank through the process of numerical simulation, which is taken as one of the constraints to set up a simple optimum designing model of sedimentation tank. The feasibility and advantages of this model based on numerical calculation are verified through the application of practical case.展开更多
Taking the distributing calculation of velocity and concentration as an example, the paper established a series of governing equations by the vorticity stream function method, and dispersed the equations by the finit...Taking the distributing calculation of velocity and concentration as an example, the paper established a series of governing equations by the vorticity stream function method, and dispersed the equations by the finite differencing method. After figuring out the distribution field of velocity, the paper also calculated the concentration distribution in sedimentation tank by using the two dimensional concentration transport equation. The validity and feasibility of the numerical method was verified through comparing with experimental data. Furthermore, the paper carried out a tentative exploration into the application of numerical simulation of sedimentation tanks.展开更多
The overall purpose of this research is to examine the impact of untreated sedimentation tank sludge water( USTSW) recycle on water quality during treatment of low turbidity water in coagulation—sedimentation process...The overall purpose of this research is to examine the impact of untreated sedimentation tank sludge water( USTSW) recycle on water quality during treatment of low turbidity water in coagulation—sedimentation processes. 950 m L of raw water and different concentrations of 50 m L USTSW are injected into six 1 000 m L beakers without coagulant.The results indicate that USTSW characterized as accumulated suspended solids and organic matter has active ingredients,which possess the equivalent function of coagulant. The optimal blended water turbidity is in the range of 10-20 NTU,within which USTSW recycle achieves the highest save coagulant rate. The mechanism of strengthening coagulation effect when USTSW recycle mainly depends on the chemical effect and physical effect. What is more,through scanning electron microscopy( SEM),it is found that the floc structures with USTSW recycle are more compact than those without USTSW recycle. Besides,the water quality parameters of color,NH3-N,CODMn,UV254,total aluminum,total manganese when USTSW recycle is better than the raw water without recycle,indicating that USTSW recycle can improve water quality with strengthening coagulation effect.展开更多
Sedimentation tanks and clarifiers play a significant role in an active sludge system, and the efficiency of the whole system is closely related with the design and operation of the sedimentation tanks. This paper foc...Sedimentation tanks and clarifiers play a significant role in an active sludge system, and the efficiency of the whole system is closely related with the design and operation of the sedimentation tanks. This paper focuses on the sludge concentration in each cross-section of the sedimentation tank. We measured the sludge concentration to explore its distribution inside the tank, carried in-situ tests to research the fluid pattern and real operational rules of the sedimentation tank. We also used the computational fluid dynamics (CFD) software, PHOENICS 3.5, to simulate the solid-liquid two-phase fluid inside the tank and describe the sludge concentration distribution. The numerical results indicate obviously a sludge-water interface and a compression interface inside the sedimentation tank, a stratified sedimentary region with uniform concentration and a compression region with high concentration at the bottom of the tank. Although the simulated concentrations deviated slightly from those of in-situ tests, they were still acceptable for identifying the sludge interfaces and fluid pattern inside a sedimentation tank, which are important parameters for optimizing the tank size and improving the settling efficiency.展开更多
Umbrella-type mud-water diversion labyrinth sedimentation device,which is characterized by the combination of two swash plate and wing plate into an umbrella type with a set angle,the angle range of the two swash plat...Umbrella-type mud-water diversion labyrinth sedimentation device,which is characterized by the combination of two swash plate and wing plate into an umbrella type with a set angle,the angle range of the two swash plate is 15º--100º,the vertical height of the swash plate is 60-70 mm,the parallel axis of the wing plate is the vertical direction,the height is 10-20 mm.the whole adopts the modular combination mode,and can be freely combined and disassembled according to different pond design,swash plate The interval(sedimentation distance)can be freely adjusted,mud take the mud road and water take the water road,to avoid the mutual interference of the water and mud road,to achieve the stability of the water quality.The turbidity of the sedimentation pond is low,stable in 0.3-2.0 NTU.展开更多
文摘The paper establishes the relationship between the settling efficiency and the sizes of the sedimentation tank through the process of numerical simulation, which is taken as one of the constraints to set up a simple optimum designing model of sedimentation tank. The feasibility and advantages of this model based on numerical calculation are verified through the application of practical case.
文摘Taking the distributing calculation of velocity and concentration as an example, the paper established a series of governing equations by the vorticity stream function method, and dispersed the equations by the finite differencing method. After figuring out the distribution field of velocity, the paper also calculated the concentration distribution in sedimentation tank by using the two dimensional concentration transport equation. The validity and feasibility of the numerical method was verified through comparing with experimental data. Furthermore, the paper carried out a tentative exploration into the application of numerical simulation of sedimentation tanks.
基金Sponsored by the Major Science and Technology Program for Water Pollution Control and Treatment(Grant No.2012ZX07408001,2014AX07405002)the National Science Foundation of China(Grant No.51108118)
文摘The overall purpose of this research is to examine the impact of untreated sedimentation tank sludge water( USTSW) recycle on water quality during treatment of low turbidity water in coagulation—sedimentation processes. 950 m L of raw water and different concentrations of 50 m L USTSW are injected into six 1 000 m L beakers without coagulant.The results indicate that USTSW characterized as accumulated suspended solids and organic matter has active ingredients,which possess the equivalent function of coagulant. The optimal blended water turbidity is in the range of 10-20 NTU,within which USTSW recycle achieves the highest save coagulant rate. The mechanism of strengthening coagulation effect when USTSW recycle mainly depends on the chemical effect and physical effect. What is more,through scanning electron microscopy( SEM),it is found that the floc structures with USTSW recycle are more compact than those without USTSW recycle. Besides,the water quality parameters of color,NH3-N,CODMn,UV254,total aluminum,total manganese when USTSW recycle is better than the raw water without recycle,indicating that USTSW recycle can improve water quality with strengthening coagulation effect.
基金the Key Subject Supporting Project of Shanghai Government (No. 042312067)
文摘Sedimentation tanks and clarifiers play a significant role in an active sludge system, and the efficiency of the whole system is closely related with the design and operation of the sedimentation tanks. This paper focuses on the sludge concentration in each cross-section of the sedimentation tank. We measured the sludge concentration to explore its distribution inside the tank, carried in-situ tests to research the fluid pattern and real operational rules of the sedimentation tank. We also used the computational fluid dynamics (CFD) software, PHOENICS 3.5, to simulate the solid-liquid two-phase fluid inside the tank and describe the sludge concentration distribution. The numerical results indicate obviously a sludge-water interface and a compression interface inside the sedimentation tank, a stratified sedimentary region with uniform concentration and a compression region with high concentration at the bottom of the tank. Although the simulated concentrations deviated slightly from those of in-situ tests, they were still acceptable for identifying the sludge interfaces and fluid pattern inside a sedimentation tank, which are important parameters for optimizing the tank size and improving the settling efficiency.
文摘Umbrella-type mud-water diversion labyrinth sedimentation device,which is characterized by the combination of two swash plate and wing plate into an umbrella type with a set angle,the angle range of the two swash plate is 15º--100º,the vertical height of the swash plate is 60-70 mm,the parallel axis of the wing plate is the vertical direction,the height is 10-20 mm.the whole adopts the modular combination mode,and can be freely combined and disassembled according to different pond design,swash plate The interval(sedimentation distance)can be freely adjusted,mud take the mud road and water take the water road,to avoid the mutual interference of the water and mud road,to achieve the stability of the water quality.The turbidity of the sedimentation pond is low,stable in 0.3-2.0 NTU.
