Tennessee Wastewater Operator Practice Exam

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

1. Increase nutrient concentrations

2. Improve water color

3. Reduce loadings to secondary treatment

4. Eliminate all pathogens

The correct answer is: Reduce loadings to secondary treatment

The main purpose of primary treatment in wastewater management is to reduce loadings to secondary treatment. During primary treatment, physical processes such as screening, sedimentation, and floatation are utilized to remove a significant portion of suspended solids and organic matter from the wastewater. This step is crucial because it lessens the volume and strength of the wastewater that must undergo further treatment in secondary processes. By minimizing the load on secondary treatment, it enhances the efficiency and effectiveness of biological treatment methods that follow, ultimately leading to better overall treatment performance and reducing operational costs. In the context of the other options, increasing nutrient concentrations is not a goal of primary treatment, as the focus is primarily on solids removal rather than nutrient enhancement. Improving water color is typically associated with secondary and tertiary treatment processes, where further treatment can address aesthetic qualities of the water. While reducing pathogens is an important concern in wastewater treatment, primary treatment does not eliminate all pathogens; this is typically addressed more effectively in subsequent treatment stages.