Tennessee Wastewater Operator Practice Exam

Selectors in wastewater treatment are useful for what purpose?

1. Enhancing overall system flow

2. Controlling growth of some filaments

3. Reducing sludge volume

4. Eliminating chemical usage

The correct answer is: Controlling growth of some filaments

Selectors in wastewater treatment play a critical role in controlling the growth of certain filaments, which can significantly impact the efficiency and performance of a treatment system. In particular, selectors are designed to create conditions that favor the growth of desirable microorganisms while suppressing those that lead to filamentous bulking and foaming problems. This selective pressure is essential for maintaining a balanced microbial population, ultimately resulting in better sedimentation and a more stable treatment process. The importance of managing filamentous organisms cannot be overstated; excessive growth of undesirable filaments can lead to sludge bulking, which complicates the separation of solids from liquids in the clarifiers and can even disrupt the overall treatment process. By utilizing selectors, operators can enhance the efficiency of biological treatment processes and ensure that the effluent quality meets regulatory standards. While options regarding enhancing system flow, reducing sludge volume, and eliminating chemical usage may also be relevant to wastewater treatment practices, they do not accurately capture the primary function of selectors. They are specifically engineered to address the challenges posed by filamentous bacteria, making control over these organisms the most critical purpose of selectors in the treatment process.