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a form of coagulation in which fine particles suspended in a liquid or gas form loose, fluffy clusters called floes. In disperse liquid systems, such as sols, suspensions, emulsions, and latexes, flocculation occurs through thermal, mechanical, or electrical means. Soluble polymers, particularly polyelectrolytes, are effective flocculants.

The action of polymeric flocculants is usually explained as the simultaneous adsorption of long-chain macromolecules on several particles. The clusters that develop form flakes that can be easily removed by settling or filtering. Flocculants, for example, polysilicic acid or polyacrylamide, are widely used in treating water for industrial or domestic needs. They are also used in mineral concentration, in the pulp and paper industry, in agriculture (for improving soil structure), in the separation of valuable products from industrial wastes, and in the decontamination of industrial sewage. In water purification, polymeric flocculants are usually used in concentrations of 0.1–5 mg/liter. Flocculation by the organic substances present in bodies of water in nature is an important factor in the self-purification of such waters.


Kul’skii, L. A. Teoreticheskie osnovy i tekhnologiia konditsionirovaniia vody, 2nd ed. Kiev, 1971. Page 138.
Voiutskii, S. S. Kurs kolloidnoi khimii, 2nd ed. Moscow, 1975.
Veitser, Iu. I., and D. M. Mints. Vysokomolekuliarnye flokulianty v protsessakh ochistki vody. Moscow, 1975.


References in periodicals archive ?
Electrostatic interactions, charge neutralization and bridging are among the major interactions involved in dye adsorption and coagulation flocculation.
Coagulation and flocculation studies were performed in a standard jar-test apparatus (Jar Tester Model CZ150) comprises of six paddle rotors (24.
When MRF is under shear stress, flocculation constituents rotate, deform and even crack when the force applied is strong enough.
By contrast, free radical copolymerization has been proven to be a convenient and effective approach, which integrates specific functional groups of monomers while simultaneously generating some new features for improvement of flocculation ability [20-22].
The efficiency of the flocculation was evaluated using the following equation proposed by Zuharlida et al.
Bridging flocculation occurs at low concentrations of polymeric thickener in a colloidal dispersion in which a single polymer chain adsorbs on two or more particles and "binds" them together.
the interactive effects of PAM and clay properties on clay flocculation and PAM adsorption and desorption, is essential to providing scientific knowledge for use of PAM in different soils or regions to reduce soil erosion and to improve soil physical properties.
Scientists and engineers apply these tools to understand, optimize, and control the flocculation process and improve dewatering efficiency in real time.
In another study, VBT with 4,500 ppm of COD was subjected to chemical flocculation and it was achieved 80% of COD removal (Ryan, et al.