One of the most essential classes of chemicals used in water treatment is coagulants. Coagulation is the process of aggregating fine particles in water into larger clusters, or flocs, that can be easily removed. The most commonly used coagulants are aluminum sulfate (alum) and ferric chloride. When these chemicals are added to water, they neutralize the charges on suspended particles, allowing them to bind together. As a result, larger particles are formed, which can then be removed through sedimentation or filtration. Coagulation is critical for removing turbidity and settling out organic matter, microorganisms, and other contaminants.