Flocculation

[clarification needed] According to the IUPAC definition, flocculation is "a process of contact and adhesion whereby the particles of a dispersion form larger-size clusters".

[5] In colloid chemistry, flocculation refers to the process by which fine particulates are caused to clump together into a floc.

High dispersibility of soil colloids not only directly causes turbidity of the surrounding water but it also induces eutrophication due to the adsorption of nutritional substances in rivers and lakes and even boats under the sea.

[6] Flocculation is thus the initial step leading to further ageing of the emulsion (droplet coalescence and the ultimate separation of the phases).

[9] In civil engineering, and in the earth sciences, flocculation is a condition in which clays, polymers or other small charged particles become attached and form a fragile structure, a floc.

The addition of synthetic flocculants to the bioreactor can increase the average particle size making microfiltration more efficient.

For drinking water, typical treatment processes consist of grates, coagulation, flocculation, sedimentation, granular filtration and disinfection.

[16] The coagulation and flocculation steps are similar, causing particles to aggregate and fall out of solution, but may use different chemicals or physical movement of water.

[17] A variety of salts may be added to adjust the pH and act as clarifying agents, depending on the water chemistry.

[17] Polydiallyldimethyl ammonium chloride (polyDADMAC) and epiDMA (a copolymer of epichlorohydrin and dimethylamine) are common choices, though these can produce carcinogenic nitrosamines.

[18] Chitosan is not only biodegradable but also exhibits a unique ability to bind with a wide range of contaminants, including heavy metals and organic pollutants, effectively removing them from water sources.

Usually, in higher pH ranges, in addition to low ionic strength of solutions and domination of monovalent metal cations, the colloidal particles can be dispersed.