Which component is typically removed first in the primary sewage treatment process?

In primary sewage treatment, the main focus is on the removal of solids from wastewater. Suspended solids are typically the first component removed during this stage of treatment. This is achieved through processes such as sedimentation, where the heavier solid particles settle at the bottom of a treatment tank, forming a sludge layer.

Removing suspended solids is crucial because these particles can carry a variety of contaminants, including pathogens, organic matter, and nutrients. By eliminating these solids first, the treatment process helps reduce the overall burden on subsequent treatment stages, which may focus more on biological and chemical processes to remove other types of pollutants. While pathogens, nutrients, and organic compounds are important to address in later stages of sewage treatment, the immediate priority in primary treatment is to clear out the larger particles and solids to facilitate better flows and conditions for further treatment steps.