What does the term "flocculation" refer to in water treatment?

The term "flocculation" in water treatment specifically refers to the process of forming aggregates of fine particles or flocs. This occurs when certain chemicals, known as coagulants, are added to the water. These coagulants encourage small suspended particles to clump together, creating larger particles that can be more easily removed from the water through sedimentation or filtration.

This process is crucial in preparing water for subsequent treatment steps, as it enhances the effectiveness of sedimentation by increasing the size of the particles that need to be removed. The formation of these aggregates not only improves the clarity of the water but also helps in reducing the amount of chlorine or other disinfectants needed in the final disinfection step.

While the process of settling of solid particles and the mixing of chemicals may seem related, they do not accurately capture the specific action that flocculation entails. Similarly, the measurement of chemical concentrations does not pertain to the physical or chemical processes involved in the formation of particle aggregates.