Texas Wastewater Class B Practice Exam

If an operator notices excessive air usage with no change in organic or hydraulic loading in an activated sludge system, what could be a possible issue?

1. Improper blending of chemicals

2. Leaks in the system piping

3. Insufficient bacteria in the system

4. Low water temperatures

The correct answer is: Leaks in the system piping

Excessive air usage in an activated sludge system, despite no changes in organic or hydraulic loading, can often indicate leaks in the system piping. When there are leaks, the system must compensate for the lost air, leading to increased air flow and usage to maintain adequate aeration levels. This can significantly affect the efficiency of the aeration process and may suggest an underlying issue that requires immediate attention. While other options may seem relevant, they do not directly address the symptoms of excessive air consumption without changes in loading. For example, improper blending of chemicals typically affects treatment efficacy rather than air usage. Insufficient bacteria would lead to inadequate treatment, potentially resulting in other observable indicators, but not specifically increased air usage. Low water temperatures can affect the overall biological activity but do not inherently cause an increase in air requirement unless there is a significant impact on oxygen solubility or bacterial performance. Thus, the identification of leaks as a potential issue is most aligned with the context of excessive air consumption.