Tennessee Wastewater Operator Practice Exam

What is one potential consequence of poor solids settling in wastewater treatment?

1. Reduced chemical usage

2. Increased odor problems

3. Higher energy consumption

4. Lower nutrient removal efficiency

The correct answer is: Lower nutrient removal efficiency

In wastewater treatment, inefficient solids settling can have a significant impact on nutrient removal efficiency. When solids do not settle properly, they may remain suspended in the treatment processes. This can lead to a variety of issues, including interference with biological processes designed to remove nutrients such as nitrogen and phosphorus. These nutrients often bind to solids, so when the solids are not effectively separated, the treatment system is unable to adequately process and remove these contaminants. As a result, the effluent can have higher concentrations of nutrients, which can contribute to water quality issues such as algal blooms in receiving waters. The other potential consequences of poor solids settling, while relevant, do not directly point to nutrient removal efficiency. Increased odor problems may arise due to the decomposition of organic matter that is not effectively removed, higher energy consumption could result from needing more mechanical processes to handle poorly settling solids, and reduced chemical usage typically would be a result of better solids handling, rather than poor performance. Thus, the direct correlation to lower nutrient removal efficiency makes that answer particularly significant in the context of wastewater treatment.