Tennessee Wastewater Operator Practice Exam

How can an operator determine when the air filters on aeration blowers need cleaning?

1. By visually inspecting the filters

2. By measuring the differential pressure between inlet and discharge side of the filter

3. By checking the noise level of the blower

4. By measuring the air temperature

The correct answer is: By measuring the differential pressure between inlet and discharge side of the filter

The correct answer is determined by measuring the differential pressure between the inlet and discharge side of the filter. This method is critical because it gives a quantitative assessment of the performance of the air filters. As filters become clogged with particulates, the differential pressure increases, indicating that the blower is working harder to push air through the blockage. A significant increase in differential pressure signals that the filters need cleaning to maintain efficient operation of the aeration system and to ensure optimal air supply for the biological treatment process. Visual inspections can provide some insights into the condition of the filters, but they may not reveal subtle blockages or issues that could affect airflow and system efficiency. Similarly, checking the noise level of the blower may provide indications of overall performance but does not specifically indicate filter condition. Measuring air temperature is not a reliable indicator of filter cleanliness either, as temperature variations can arise from various factors unrelated to filter status. Thus, differential pressure measurement is the most effective and reliable method for determining when air filters require cleaning.