What is the primary purpose of coagulation in water treatment?

The primary purpose of coagulation in water treatment is to aggregate particles for easier removal. Coagulation involves adding chemicals, known as coagulants, to water. These coagulants neutralize the charges on suspended particles, allowing them to clump together, or coagulate. When these particles aggregate, they form larger clusters, or flocs, which can then be removed more effectively through subsequent processes, such as sedimentation and filtration. This step is crucial for improving water clarity and overall quality by removing turbidity-causing particles, organic matter, and microorganisms.

In the context of the other options, while lowering pH might be a part of some water treatment processes, it is not the primary function of coagulation. Removing dissolved gases is typically addressed through aeration or other methods, and increasing water temperature is not associated with coagulation but may occur during various treatment processes. Thus, coagulation's main role is clearly focused on enhancing the removal of suspended particles through aggregation.