What type of water treatment method uses chemical coagulation?

Chemical coagulation is a water treatment method that involves the addition of chemicals, typically coagulants, to destabilize colloidal particles and promote their aggregation. This process effectively removes impurities from water, including suspended solids, organic matter, and certain pathogens. When coagulants are added, they neutralize the charges of suspended particles, allowing them to clump together and form larger flocs, which can then be removed from the water through sedimentation or filtration.

This method is crucial in many water treatment systems and is often one of the first steps in the purification process, particularly for surface water sources. By using chemical treatment, operators can significantly improve the quality of water before it undergoes further treatment processes such as filtration or disinfection.

In contrast, physical treatments focus on methods that do not involve chemical reactions, such as sedimentation and filtration purely through physical barriers. Biological treatment typically involves the use of microorganisms to break down organic matter and is not associated with chemical coagulation. Filtration itself is a separation process but does not involve the chemical reactions necessary for coagulation to occur. Therefore, chemical treatment is the correct classification for the method that utilizes coagulation.