Which stage of wastewater treatment involves the removal of larger solids?

The stage of wastewater treatment that involves the removal of larger solids is preliminary treatment. During this initial phase, the goal is to screen and remove large debris such as sticks, plastics, and other oversized materials that could cause damage to machinery in subsequent treatment processes. This step may include physical processes like screening, grit removal, and sedimentation to efficiently separate these larger solids from the wastewater before it moves on to the next stages of treatment.

In contrast, secondary treatment focuses on the biological degradation of dissolved and suspended organic materials by microorganisms, while tertiary treatment involves advanced processes to remove remaining contaminants, including nutrients and pathogens, often using chemical or physical methods. Disinfection is primarily aimed at killing or inactivating harmful microorganisms at the end of the treatment process before the treated water is released or reused. Understanding these distinctions helps grasp the overall wastewater treatment process and the specific objectives of each stage.