Which process in water treatment involves the mixing of chemicals for flocculation reactions?

The process that involves the mixing of chemicals for flocculation reactions is flash mixing. Flash mixing is a critical step in the water treatment process where coagulants are rapidly mixed with raw water to ensure that the chemicals are evenly distributed. This rapid agitation facilitates the interaction between the coagulants and the impurities in the water—such as suspended solids, organic matter, and colloids—leading to the formation of larger aggregates known as flocs.

These flocs can then be removed during subsequent stages of treatment, such as sedimentation or filtration. Flash mixing typically occurs before the coagulation and flocculation stages, setting the stage for effective coagulation to happen.

In contrast, coagulation is the overall process that includes flocculation but does not specifically address the rapid mixing phase. Filtration refers to the physical removal of particulates after flocculation and sedimentation, and chlorination is a disinfection step to eliminate pathogens and is not involved in the chemical mixing for flocculation. Each of these processes plays a distinct role within the broader context of water treatment, but flash mixing is specifically where the quick mixing of coagulants occurs to promote flocculation reactions.