What is the primary purpose of adding coagulants in water treatment?

Adding coagulants in water treatment primarily serves to promote the aggregation of particles to form larger flocs. This process, known as coagulation, is essential in water treatment because it helps to remove suspended solids, bacteria, and other impurities from the water. When coagulants, such as alum or ferric chloride, are added to water, they cause small particles to clump together into larger masses, or flocs, which can be more effectively removed during subsequent filtration and sedimentation processes.

This is crucial for improving water clarity and quality before it reaches the filtration stage. The formation of larger flocs ensures that more contaminants are captured and settled out of the water, leading to cleaner and safer drinking water. While other processes involved in water treatment may focus on taste enhancement, mineral removal, or gas filtration, the primary function of coagulants is the aggregation of particles into flocs.