Tennessee Wastewater Operator Practice Exam

Why should brown foam be removed from the activated sludge basin and clarifier surfaces?

1. To improve odor control

2. To reduce the numbers of filamentous bacteria

3. To enhance process efficiency

4. To prevent foam overflow

The correct answer is: To reduce the numbers of filamentous bacteria

The removal of brown foam from the activated sludge basin and clarifier surfaces primarily addresses the issue of filamentous bacteria. When foam accumulates, it indicates possible excess filamentous growth, which can disrupt the biological treatment process. High numbers of filamentous bacteria can lead to poor settling characteristics in the clarifier, resulting in increased suspended solids in the effluent. This can impact overall effluent quality and compliance with discharge standards. Filamentous bacteria thrive in conditions where nutrients are abundant, and their overgrowth can lead to bulking sludge, making it difficult for the system to separate solid and liquid phases effectively. By removing the foam, which is an indicator of filamentous bacteria presence, operators help maintain the appropriate microbial balance essential for effective wastewater treatment processes. Thus, controlling the levels of filamentous bacteria helps improve operational stability and enhances the performance of the entire system. Other options address different aspects of wastewater treatment, but they do not focus specifically on the correlation between foam removal and filamentous bacteria control in this context.