What is coagulation in the context of water treatment?

• A. The process of forming larger clumps from tiny particles
• B. The neutralization of particle charges in water
• C. The sedimentation of particles in water
• D. Both A and B

Answer: (D)

Coagulation in water treatment is about making tiny suspended particles unstable so they can come together. This starts when coagulants neutralize the electrical charges on particle surfaces, which reduces the repulsion between particles and lets them collide more easily. As these collisions happen, the particles begin to stick together and form larger clusters. In practice, coagulation is often described as the combination of the chemical charge neutralization and the subsequent growth into larger clumps during gentle mixing, so the option that covers both aspects is the best choice. After these clumps form, the next step is sedimentation, where the larger particles settle out.