Describe the process of flocculation.

Flocculation is a key process in water treatment where fine particles suspended in water are agglomerated into larger clusters known as flocs. This process typically follows coagulation, which adds chemicals (coagulants) to destabilize the particles, causing them to bond together. The outcome of flocculation is the formation of these larger aggregates, which can then easily be removed from the water through sedimentation or filtration processes.

The reason this option is the correct choice is that it accurately represents the core function of flocculation, which is the uniting of tiny particles into larger, more manageable forms. The larger flocs produced are not only easier to remove but also improve the overall quality of the treated water by reducing turbidity and enhancing the effectiveness of subsequent purification steps.

In contrast, breaking down large particles refers to a process of disintegration, which is not part of flocculation. Removing dissolved substances pertains more to processes like adsorption or advanced oxidation, which operate differently than flocculation. Filtering water through sand is related to the physical removal of particles but does not involve the agglomeration process that defines flocculation.