California WasteWater Treatment Operator Grade 2 Certification Practice Test

The main objective of primary wastewater treatment is solid-liquid separation to reduce solids concentration. During this phase of the treatment process, the primary goal is to remove large solids and settleable materials from the wastewater. This is typically achieved through processes such as sedimentation, where heavier solids settle to the bottom of a treatment tank, forming a sludge layer, while lighter materials and liquids remain above.

This step is critical for preparing the wastewater for subsequent secondary treatment processes, which focus on further breaking down organic matter and removing finer particles. Although primary treatment may lead to some degree of pathogen removal and organic material reduction, its primary function is to effectively reduce the concentration of solids and suspended materials in the wastewater. By doing so, it plays a vital role in improving the efficiency of further treatment stages and minimizing the potential environmental impact of the effluent.

Disinfection, biodegradation, and complete pathogen removal are typically not the focus in primary treatment but are handled in later stages of the wastewater treatment process.