What is the primary method used for removing suspended solids?

The primary method used for removing suspended solids in wastewater treatment is settling. This process relies on gravity to separate solid particles from the liquid. When wastewater is allowed to sit in a tank, suspended solids tend to settle at the bottom due to their density. This sedimentation process is often facilitated in a sedimentation basin or clarifier, where the heavier particles form sludge at the bottom, allowing the clearer liquid above to be decanted or further treated.

While methods like filtration, the activated sludge process, and flotation also play roles in solid removal, settling is most fundamental and widely employed as the first line of defense in solids removal in wastewater treatment. Filtration typically targets finer particles after initial settling, the activated sludge process is involved in biological treatment rather than direct removal of solids, and flotation is used for specific types of solids and can enhance the settling process but is not the primary method.