Flocculants are used in wastewater treatment to assist in the removal of suspended solids by flocculating them (ie. causing small particles to clump together to make them sink/float). Flocculants are available in two forms; anionic and cationic. In general, an anionic flocculant will be effective for clays, salts and metal hydroxides, while cationic agglomerate silicas and organic substances.