Wastewater Treatment Operator Certification Practice Test

What is an air gap?

1. A distance between blowers in an activated sludge system

2. The vertical distance between the surface of wastewater and the top of basin

3. Backflow prevention

4. Type of aeration equipment

The correct answer is: Backflow prevention

An air gap is best described as backflow prevention. Specifically, it refers to a physical separation between the source of water supply and the place where it is discharged, which prevents any contaminant from entering the potable water system. In wastewater treatment, maintaining an air gap is crucial to avoid pollution and ensure that treated water does not flow back into the drinking supply. This is especially important in systems where wastewater could potentially mix with clean water, posing a health risk. The other options relate to components of the wastewater treatment process but do not accurately describe what an air gap is. For example, the distance between blowers in an activated sludge system (the first option) does not pertain to the concept of air gaps. Similarly, the vertical distance between the surface of wastewater and the top of a basin is not a direct indicator of an air gap, although it is related to the physical design of wastewater systems. Lastly, the type of aeration equipment (the fourth option) refers to the mechanisms used to introduce air into the water but does not encompass the idea of an air gap.