Tennessee Wastewater Operator Practice Exam

What impact does adding more oxygen have on the treatment of wastewater?

1. Increases chemical reactions

2. Decreases nutrient removal

3. Reduces pH levels

4. Promotes slime buildup

The correct answer is: Increases chemical reactions

Adding more oxygen to the treatment of wastewater significantly increases chemical reactions, particularly those involved in the biological treatment processes. In aerobic treatment systems, microorganisms use oxygen to break down organic matter. This enhanced availability of oxygen supports faster and more efficient microbial activity, which leads to a more effective breakdown of pollutants. The process is essential in aerobic digestion and activated sludge systems, where the microbial oxidation of waste occurs. As microorganisms metabolize organic substances in the presence of oxygen, they convert these materials into carbon dioxide, water, and biomass, which can then be separated from the treated water. This increased rate of metabolic activity due to enhanced oxygen levels directly impacts the overall efficiency of the wastewater treatment process, resulting in better removal of biochemical oxygen demand (BOD) and other harmful compounds. In contrast, the other options do not reflect the primary effects of adding oxygen in wastewater treatment. While nutrient removal can be affected by various factors, increased oxygen typically supports rather than decreases nutrient removal. Oxygen does not directly reduce pH levels in a significant way; pH changes are generally influenced by other chemical processes. Lastly, promoting slime buildup is not a key effect of increased oxygen; rather, excessive organic loading can contribute to such occurrences in some contexts. Therefore, the impact of