Tennessee Wastewater Operator Practice Exam

As temperature decreases, what is the following effect on biological activity?

1. Biological activity increases

2. Biological activity remains unchanged

3. Biological activity slows down

4. Biological activity is eliminated

The correct answer is: Biological activity slows down

As temperature decreases, biological activity typically slows down due to the lower kinetic energy of molecules in the environment. In the context of wastewater treatment, microorganisms play a crucial role in breaking down organic matter. These microorganisms are sensitive to temperature changes; when the temperature drops, their metabolic processes and enzymatic reactions become less efficient. The reduced temperatures can lead to slower rates of growth and reproduction for these microorganisms, ultimately resulting in a decrease in the overall biological activity within the treatment system. This slowdown can impact the effectiveness of processes like aerobic and anaerobic decomposition, making it essential for operators to monitor and manage temperature conditions when assessing biological treatment performance. It is important to understand that while some microorganisms are adapted to survive and even thrive in colder conditions, the general trend is a reduction in biological activity as the temperature falls below optimal ranges.