What is the main purpose of primary treatment in wastewater management?

The main purpose of primary treatment in wastewater management is to settle out solids from wastewater. This is achieved through physical methods, primarily sedimentation, where heavier solids fall to the bottom of a treatment tank, forming sludge, while lighter materials, such as oils and grease, rise to the surface as scum. This process significantly reduces the overall volume of solids that need to be further treated, helps to clarify the wastewater before it undergoes secondary treatment, and separates materials that can be more easily removed or managed in subsequent processes.

While the other options involve important aspects of wastewater treatment, they do not specifically pertain to the primary treatment phase. Pathogen removal, aeration, and chemical treatment are typically associated with secondary and advanced treatment processes. In primary treatment, the focus is primarily on the removal of suspended solids to improve the efficiency of subsequent treatment stages.