Flocculants and coagulants are two types of chemicals commonly used in water treatment to remove suspended solids and other impurities from water.
Coagulants are chemicals that are added to water to destabilize the suspended particles and bring them together. This process is known as coagulation. The coagulants neutralize the electrical charges on the particles, which allows them to come closer together and form larger particles that are easier to remove. Examples of coagulants include aluminum sulfate (alum), ferric sulfate, and polyaluminum chloride (PAC).
Flocculants are chemicals that are added after coagulation to enhance the process of settling or filtration. The larger particles created during coagulation are still too small to be removed by settling or filtration, so flocculants are added to increase the size of the particles and form larger, denser flocs that are easier to remove. Flocculants are usually long-chain polymers that bind to the particles and cause them to agglomerate.
Overall, the use of coagulants and flocculants is an effective and widely used method for water treatment, particularly in the removal of suspended solids, colour, and turbidity from water.