Organic flocculants are mostly polymers. They may be polyelectrolytes, that is, polymers carrying anionic or cationic charge, or uncharged non-ionic polymers. They may be synthetic or natural.
Flocculation is the process whereby the manifestation of destabilization is realized in practicable terms: in effect, flocculation accelerates floc formation, influences the physical characteristics of flocs formed including their strength, size and density, and governs the final number concentration of destabilized particles. Polyelectrolytes or Polymers act through a combination of cell surface charge neutralization and particle bridging to form flocs. The effectiveness of polyelectrolyte or polymer flocculants is influenced by the following factors: the molecular mass or chain length of the polymer; the charge density on the molecule; the dose used; the biomass concentration; the ionic strength and pH of the broth; and the mixing in the fluid.