Tennessee Wastewater Operator Practice Exam

What is a characteristic of stable, viscous brown foam in wastewater?

1. Indicates high nutrient levels

2. Indicates low microbial activity

3. Associated with certain filamentous organisms

4. Always harmful to treatment processes

The correct answer is: Associated with certain filamentous organisms

The characteristic of stable, viscous brown foam in wastewater is associated with certain filamentous organisms. This type of foam often forms as a result of the growth of specific filamentous bacteria that can thrive in an environment with high organic loading and nutrient levels. These organisms can contribute to the stability and viscosity of the foam due to their filamentous structures, which create a matrix that traps air and forms bubbles. In a treatment process, the presence of this type of foam can be indicative of an imbalance in the microbial population, often pointing to conditions such as nutrient overloading or a lack of grazing organisms that would normally keep filamentous bacteria in check. Understanding this association helps operators manage and maintain the proper balance of microorganisms in the treatment system to ensure effective processing of wastewater.