Tennessee Wastewater Operator Practice Exam

When biological activity slows down in wastewater treatment, what potential issue may arise?

1. Increased pH levels

2. Decreased oxygen demand

3. Increased influent toxicity

4. Reduced treatment effectiveness

The correct answer is: Reduced treatment effectiveness

When biological activity slows down in wastewater treatment, reduced treatment effectiveness is a significant potential issue. This is because the biological processes in wastewater treatment, such as the breakdown of organic matter and the removal of nutrients, largely depend on the activity of microorganisms. When these microorganisms become less active, their ability to degrade pollutants diminishes, leading to less effective treatment of the wastewater. If biological activity decreases, it can result in insufficient removal of contaminants, such as suspended solids, biochemical oxygen demand (BOD), and nutrients like nitrogen and phosphorus. This compromised treatment can lead to higher concentrations of pollutants in the effluent, which can cause environmental concerns when the treated water is discharged into water bodies. This decline in treatment effectiveness can also lead to regulatory compliance issues, as effluent quality may not meet the required standards. The other potential issues discussed in the choices, such as increased pH levels, decreased oxygen demand, and increased influent toxicity, may not directly correlate to a slowdown in biological activity. For example, while a decrease in biological activity can sometimes lead to an increase in organic matter and thus an initial rise in oxygen demand, it doesn’t inherently lead to decreased oxygen demand. Similarly, increased influent toxicity is more associated with external factors rather than a direct