Drum filter packing and shipping

2 year ago

46 0

Wuxi Feiyiya Environmental Protection Technology Co., Ltd.

 3 year year

Product details

Owing to its small land footprint and high efficiency,high-efficiency sedimentation tanks are widely used in water or wastewater treatment.For instance,the high-efficiency sedimentation system has been proven to be an efficient and promising technique for the treatment of urban stormwater runoff during the monsoon seasons by virtue of its stable suspended solids removal performance and more compact process compared to conventional flocculation.The high-efficiency sedimentation tank is primarily made up of the mixing zone and the settling zone,both of which possess complex structures.The geometric configuration of a high-efficiency sedimentation tank will influence its flow field distribution and further affect the efficiency of the flocculation and sedimentation process.Therefore,the optimization of the structural design is an important approach to achieve better wastewater treatment effects for the high-efficiency sedimentation tank.In addition,various areas of the high-efficiency sedimentation tank play different functional roles.In the mixing zone(coagulation/flocculation),the flocs should be allowed to grow up and gain enough kinetic energy to cross the overflow wall into the settling zone,while a lower hydraulic shear force is highly desirable for the settling zone to prevent the destruction of the floc structure and achieve good separation efficiency.So,the required hydraulic characteristics differ greatly in different zones of high-efficiency sedimentation tanks.In summary,the geometric structure and operational condition are the two key issues for a high-efficiency sedimentation tank.

1701220913484

The current design of water treatment reactors and the selection of operating parameters mainly depend on the experience of wastewater engineers.Although the semiempirical experimental method has provided helpful support for water treatment engineering,it is very difficult to provide detailed information about hydrodynamics in the high-efficiency sedimentation tank due to the complex characteristics of flow field distribution.Thanks to the rapid development of computer technologies,the computational fluid dynamics(CFD)method provides a powerful tool to analyze flow fields in water and wastewater treatment facilities.It was found that the flow field could be more affected by the height of the under-through channel than its width,and solids’sedimentation concentration at the bottom of the mixing zone was reduced with the decrease in the height of the under-through channel.In summary,CFD has become an efficient and cost-effective tool for the design and optimization of water treatment equipment.

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While significant progress has been made in analyzing water and wastewater treatment processes with the aid of CFD,previous studies mainly focus on specific regions of the high-efficiency sedimentation tank rather than the overall process.Moreover,few researchers pay attention to the effects of dosage of ballast media and inlet velocity on the clarification performance of high-efficiency sedimentation tanks in the CFD simulations.Therefore,this work aims to discover the distributions of the flow field in the full-scale high-efficiency sedimentation tank by the solid–liquid two-phase CFD model,in which an attempt is made to optimize the geometrical configuration and operating conditions of the sedimentation tank.The flow velocity,turbulent kinetic energy,and rate of turbulent kinetic energy dissipation are used as hydrodynamic indicators to evaluate the flocculation/sedimentation performance. Finally,a comparison between a high-efficiency settling tank and a conventional mechanically accelerated clarifier was conducted to illustrate the advantages of the high-efficiency settling tank.
1701219068346

The unstructured grid is used for the flocculation zone of the high-efficiency sedimentation tank.The multiple reference frame method(MRF), dividing the model into the rotation zone containing the stirring paddle and the stationary zone except for the stirring paddle, was employed to model the stirring process.The rotation zone was considered to be the grid encryption.The total number of grids in the current model is 2,833,212,with a mesh aspect ratio of 40.3,a mean mesh skewness of 0.28,an orthogonal quality of 0.023,and an overall mesh score of 0.8.Those parameters indicate that the current calculation meets the accuracy requirement of engineering design.

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