Flocculant

A flocculant is a chemical which causes the particles in a colloidal dispersal to clump together and form 'flocs'.

Flocculants are commonly used to facilitate the removal by filtration of particles of impurity from a liquid which would otherwise be too fine to be caught by a filter. For example, a flocculant may be used in both swimming pool and drinking water filtration to aid removal of microscopic particles which would otherwise cause the water to be cloudy and which would be difficult or impossible to remove by filtration alone.