Physical characteristics of flocs—II. Strength of floc

Characterization of kaolin flocs formed by polyacrylamide as flocculation aids

“…Floc strength is hard to characterize due to the inherent complexity, fragility and variation in floc size, shape and composition. In earlier study, floc strength was defined from the empirical relationship between the size of the surviving aggregates and the applied shear that flocs were subjected to during turbulent flow (Tambo and Hozumi, 1979). As the shear rate is increased, the maximum floc size decreases and this remains one of the most effective empirical indications of floc strength.…”

A laboratory assessment of the relative importance of turbulence, particle composition, and concentration in limiting maximal floc size and settling behaviour

“…In laboratory studies, aggregates have been formed using many different types of floccdators ranging from shaken bottles (Kranck, 1986) through simple annuiar flumes (e.g. Krone, 1962, PostmaJ967, Mehta and Partheniades, 1975, Muschenheim et al, 1989, to elaborate flocculators such as those of Tambo and Hozumi (1979) or Tsai et ai., (1987). Flocculators of two basic types, paddle and couette, have been used in experiments exarnining the effect of turbulence, usuaIiy expressed as energy dissipation rate or shear, on floc size.…”

“…Missing in out understanding of these processes is a clear definition of the factors that limit maximal floc size in the sea Given the importance of aggregation and disaggregation in a variety of applied fields, numerous laboratory studies have focused on the control of floc size and its effect on settling behaviour. In general, these investigations have found that maximal floc size decreases with increasing fluid shear (e-g. Tambo and Hozumi, 1979) and that particle composition affects maximal floc size (e-g. Kranck and Milligan, 1980). Some work has also been carried out on the effect of suspension concentration, yielding arnbiguous results (e-g. Tsai et al, 1987, Oles, 199 1).…”

Modeling particle-size distribution dynamics in a shear-induced breakage process with an improved breakage kernel: Importance of the internal bonds

“…However, the solid volume observed, would decrease with the size of particles according to a power-law relationship [11,15,28], i.e.…”

“…They provided an elaborate model for breakage kinetics. Other researchers [14][15][16][17][18] found that the fragility of an aggregate is generally proportional to its size -as the aggregate increases in size, it becomes more vulnerable to breakage. Even though the process of colloidal aggregate breakage has been studied in the literature by many researchers through both experimental and modeling approaches [19,20], many questions remained unanswered, such as breakage manners, bonding interactions between the particles within an aggregate body and the irregular shape of fractal.…”