Texas Wastewater Class B Practice Exam

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Prepare for the Texas Wastewater Class B Exam. Study with flashcards and multiple choice questions, each question accompanied by hints and explanations. Ace your exam!

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How does the rate of returned sludge affect the treatment process?

Affects the concentration of incoming BOD
Influences the growth rate of microorganisms
Affects the temperature in the aeration tank
Has little to no impact on the treatment process

The correct answer is: Influences the growth rate of microorganisms

The rate of returned sludge significantly influences the growth rate of microorganisms within the biological treatment process. In wastewater treatment, returned sludge is comprised of activated sludge that is collected from the settling tank and sent back to the aeration tank. The concentration of this returned sludge directly affects the biomass present in the system. A higher return sludge rate leads to more microorganisms being available to break down organic matter, thereby increasing the efficiency of the biological treatment process. This enhancement in microbial activity is essential for effectively reducing biochemical oxygen demand (BOD) and promoting stabilizing conditions in the aeration tanks, enabling better treatment outcomes. While other aspects such as temperature and concentration of incoming BOD are important, they are not directly influenced by the rate of returned sludge in the same manner.