Water treatment flocculants are chemical substances used to aid in the removal of suspended solids, organic matter, and other impurities from water during the clarification or filtration process. These flocculants promote the aggregation of fine particles into larger, settleable flocs, making it easier to separate them from the water.

Here are some commonly used types of flocculants in water treatment:

1. Inorganic Flocculants:

   - Alum (aluminum sulfate): It is a widely used coagulant/flocculant that forms aluminum hydroxide flocs. Alum is effective in removing suspended solids and precipitating phosphates.

   - Ferric chloride: It is another common coagulant/flocculant that forms iron hydroxide flocs. It is effective in removing color, turbidity, and heavy metals.

2. Organic Flocculants:

   - Polyacrylamide (PAM): Polyacrylamide is a synthetic polymer that can be cationic, anionic, or non-ionic. It is highly effective in particle aggregation and sedimentation and is widely used as a flocculant in water treatment processes.

   - Polyelectrolytes: These are water-soluble polymers with high charge density, which helps in destabilizing suspended particles and promoting flocculation.

3. Natural Flocculants:

   - Chitosan: It is derived from chitin, a natural polymer found in the exoskeleton of crustaceans. Chitosan has flocculating properties and can be used as an alternative to synthetic flocculants.

   - Starch and cellulose derivatives: These natural polymers can act as flocculants and are sometimes used for water treatment applications.

The selection of the appropriate flocculant depends on various factors, including the specific properties of the water to be treated, the type and concentration of impurities, as well as the desired treatment efficiency. It is important to consult water treatment experts or professionals to determine the most suitable flocculant and its optimal dosage for a particular water treatment process.