Tennessee Wastewater Operator Practice Exam

What does the presence of large amounts of crisp white foam in an activated sludge basin usually indicate?

1. High temperatures

2. Start up conditions

3. Excessive sludge age

4. Low dissolved oxygen levels

The correct answer is: Start up conditions

The presence of large amounts of crisp white foam in an activated sludge basin is generally indicative of start-up conditions. During the initiation phase of an activated sludge process, conditions are often unsteady as the microbial population is developing and adjusting to the new environment. This can lead to the formation of foam due to the presence of surfactants, which are organic compounds that lower the surface tension of liquids and can be produced by microbial activity. In the context of wastewater treatment, particularly during the start-up phases, the formation of this foam can be attributed to the abundant growth of microorganisms and their metabolic activities that can lead to the accumulation of air bubbles, thereby creating visible foam in the basin. Understanding this phenomenon is crucial for operators, as it can guide them in monitoring the health and operational status of the treatment system.