How does coagulation help remove tiny particles suspended in water?

In a water supply system, coagulation is a critical chemical process used to remove tiny, suspended particles that are too light to settle on their own.1

The process works by adding chemicals, known as coagulants—such as aluminum sulfate (alum)—to the water. These chemicals neutralize the charges on suspended particles, allowing them to collide and clump together into larger, heavier masses of solids called "floc".12

Coagulation typically occurs in two stages:
* Rapid Mixing: Chemicals are dispersed quickly throughout the water to ensure a complete chemical reaction.1
* Flocculation: A period of gentle, slow agitation follows, which encourages further particle collisions and promotes the growth of larger floc.21

Once the particles have been aggregated into these heavier clumps, they can be effectively removed through sedimentation, where the floc settles to the bottom of a basin to be cleared away as sludge. This step is essential for preparing water for subsequent filtration and disinfection.21