Physical characteristics of flocs—I. The floc density function and aluminium floc

Tambo, Norihito

doi:10.1016/0043-1354(79)90033-2

Cited by 391 publications

(151 citation statements)

References 4 publications

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“…In a particular study by Lagvankar et al (1968) it was found that flocs generated during drinking water treatment reduced in densities with increasing size. Similar observations were reported by Tambo et al (1979).…”

Section: Modeling Resultssupporting

confidence: 81%

Experimental and modeling investigation of sewage solids sedimentation based on particle size distribution and fractal dimension

2009

Int. J. Environ. Sci. Technol.

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Sewage solids are usually characterized by non-specific parameters such as suspended solids. The suspended solids has been shown to be an inadequate index for advanced water treatment processes. In this study, the sewages solids particle size distribution was used to provide more detailed information on sewage characteristic. It is hoped that, by introducing particle size distribution, the mechanism of sewage solids sedimentations can be better understood. The particle size distribution of the domestic sewage was measured by the Malvern® laser scattering technique to link to its settlement efficiency. Experimental results show that 77 % of particle volume was removed during the 90 min settling, of which 71.2 % of particle volume was removed in the initial 30 min. The submicron particles were found to be removed by co-settling with large particles. The fractal dimensions of sewage solids could also be derived from the laser scattering measurement. The fractal dimension could also provide useful information on the shape and density of sewage solids. A mathematical model considering the particle sizes, shapes and density changes was then constructed to simulate the settlement of raw sewage particles. Comparison of the modeling results based on discrete and flocculant settling theory shows that settlement can be better predicted by considering the fractal nature of particles. The particle size distribution and fractal dimension data measured by Malvern® laser scattering technique have been shown to be valuable data for in-depth understanding of the mechanisms of sewage solids sedimentation.

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Section: Modeling Resultssupporting

confidence: 81%

Experimental and modeling investigation of sewage solids sedimentation based on particle size distribution and fractal dimension

2009

Int. J. Environ. Sci. Technol.

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“…Therefore, the fractal dimension was determined as a function of the process variables in order to verify whether changes in coagulation rates are to be attributed to different values of 1):. The fractal dimension proved to be independent of impeller speed and of concentration of solids, in agreement with the findings of Tambo and Watanabe (1979) and Oles (1992). However, it was found to be slightly different for the various polystyrene lattices that were used in the course of the aggregation experiments.…”

Section: Dependency Of Coagulation Rate On Process Variablessupporting

confidence: 77%

“…However, experiments (Tambo and Watanabe, 1979;Klimpel and Hogg, 1986;Oles, 1992) have shown that the aggregates formed by shear coagulation are usually 'fractal-like' (Schmidt-Ott et al, 1990) with floc density ( = 1 -porosity) decreasing with floc size according to a power law: where the fractal dimension, D:, is less than the dimension of space, 3. Substituting q~i = i(a/Ri) 3 into eq.…”

Section: K a Kusters Et Almentioning

confidence: 99%

Aggregation kinetics of small particles in agitated vessels

Kusters

Wijers

Thoenes

1997

Chemical Engineering Science

227

272

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Abstract--Rapid coagulation by turbulence in stirred tanks was studied for particles and aggregates smaller than the Kolmogorov microscale. The coagulation kinetics are determined by the floc structure and by the hydrodynamic and colloidal interactions between the colliding particles. The collision efficiency for doublet formation in the heterogeneous shear field of a stirred tank follows from particle trajectory analysis of solid particles in simple shear flow, provided the simple shear rate is made to correspond to the residence time weighted turbulent shear rate. Experimentally, the resulting aggregates proved to be fractal-like with their porosity increasing with aggregate size. Porosity within the aggregates results in penetration of the floc surface by the fluid flow, giving rise to enhanced collision efficiencies compared to solid particles. The collision efficiencies between porous flocs may be estimated by a model that pictures a porous floc as consisting of an impermeable core and a completely permeable shell. With the collision efficiencies from this shell-core model the aggregate growth could be described adequately.

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“…Tambo and Watanabe reported that alum floc density decreases with an increase in floc size [30]. Thus, in an attempt to explore improved filtration performance by the generation of a stronger, denser floc, 10 mg/l of alum was added in addition to the varying doses of M. oleifera.…”

Section: Screening Study With M Oleifera and Alum Coagulant Additionmentioning

confidence: 99%

Innovative physico-chemical treatment of wastewater incorporating Moringa oleifera seed coagulant

Bhuptawat

Folkard

Chaudhari

2007

Journal of Hazardous Materials

160

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Physical characteristics of flocs—I. The floc density function and aluminium floc

Cited by 391 publications

References 4 publications

Experimental and modeling investigation of sewage solids sedimentation based on particle size distribution and fractal dimension

Experimental and modeling investigation of sewage solids sedimentation based on particle size distribution and fractal dimension

Aggregation kinetics of small particles in agitated vessels

Innovative physico-chemical treatment of wastewater incorporating Moringa oleifera seed coagulant

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