1995 Fiscal Year Final Research Report Summary
Hydrodynamic Unit Processes Involved in the Transportation of Flocculated Suspension
| Project/Area Number |
05806031
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Irrigation, drainage and rural engineering/Rural planning
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| Research Institution | University of Tsukuba |
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Principal Investigator |
ADACHI Yasuhisa University of Tsukuba, Institute of Agricultural & Forest Eng., Research Associate, 農林工学系, 助手 (70192466)
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| Project Period (FY) |
1993 – 1995
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| Keywords | Floc / Kinetics / Flocculation Rate / Sedimentation / Scaling Law / Montmorillonite / Viscosity / Rapid Coagulation |
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| Research Abstract |
The transport phenomena of the flocculated suspension has been studied from many viewpoints of practical applications such as solid-liquid separation in the water and wastewater treatments. However, most of the previous investigation has been conducted without definite characterization of the physicochemical properties of used materials which form flocs and hydrodynamic condition of the suspension which surrounds flocs. In the present investigation, series of analyzes into the unit hydrodynamic processes involved in the transportation of flocculated suspension ; the kinetics of flocculation, the sedimentation of a single floc and the rheology of flocculated suspension have been carried out using flocs formed with well-characterized colloidal material in terms of flocculation. The obtained results are summarized as follows :
(1) The rate of coagulation was analyzed with an assumption of simple additivity of orthokinetics and perikinetics. The experimental results demonstrated that this a
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ssumption can be used in the practical sense. In addition, the applied mixing oparation was standardized in terms of collision rate between colloidal particle.
(2) The standardized mixing opation was applied to analyze the kinetics of bridging flocculation. It was found that the conformation of polymer in the solution state has a direct influence on the rate of bridging flocculation. Consistent result with a picture of kinetically controlled polymer adsorption was also obtained.
(3) The sedimentation velocity of a formed floc was measured as a function of floc diameter. The result confirmed the validity of computer simulation to predict the scaling studture of a floc. It was demonstrated that the reported result by Tambo on the settling velocity of a floc is quantitatively misleading.
(4) The viscosity of Na-montmorillonite suspension was analyzed flocculated under alkaine condition. It was clarified that the effect of hydrodynamic interaction is significant even in the dilute limit and taht the state of hydration is a important factor to predict the transpor properties of the suspension. Less
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