According to the chemical composition, flocculant can be divided into inorganic flocculants, organic flocculants and microbial flocculants three categories.

   Inorganic flocculant including aluminium salt, ferric salt and polymer. Organic flocculants in accordance with the charge properties of polymerization monomer charged groups, can be divided into anionic polyacrylamide, cationic polyacrylamide, nonionic polyacrylamide, amphoteric polyacrylamide to wait for a few kinds, according to its source and can be divided into synthetic and natural polymer flocculant two kinds big. In practical application, often according to the nature of inorganic flocculant and organic flocculant is different, they are complex, made from inorganic organic composite flocculant. Microbial flocculant is a combination of modern biology and water treatment technology, is the current research development and application of flocculants is an important direction.