Which process involves chemical addition that neutralizes particle charges, allowing aggregation?

• A. Flocculation
• B. Coagulation
• C. Sedimentation
• D. Disinfectant added

Answer: (B)

Coagulation is the process where a coagulant chemical is added to water to neutralize the surface charges on suspended particles. This charge neutralization reduces electrostatic repulsion between particles, destabilizing the colloids so they can come together and start forming aggregates. That initial destabilization is what makes aggregation possible, and it sets the stage for the next step, flocculation, where gentle mixing helps these particles grow into larger flocs that can then be removed by sedimentation. Disinfectants don’t promote aggregation; they inactivate microbes, and flocculation is the physical-chemical step that follows coagulation to build larger particles.