Florida Drinking Water Operator "B" Practice Test

How is increased aeration in air stripping towers achieved?

1. By reducing water flow

2. By packing and counter current air flow

3. By adding chemicals

4. By increasing water temperature

The correct answer is: By packing and counter current air flow

Increased aeration in air stripping towers is effectively achieved through packing and counter current air flow. This method enhances the contact between water and air, which is crucial for stripping volatile contaminants from the water. Packing in an air stripping tower consists of materials that increase the surface area for gas-liquid interaction. As water flows down through the packing, air is introduced from the bottom and flows upward in a counter current direction. This counter current flow maximizes the contact time between the rising air and the descending water, allowing for more efficient transfer of volatile compounds from the water to the air. The design and operation of the tower facilitate the movement of air, helping to improve the overall effectiveness of the aeration process. In contrast, the other methods, like reducing water flow, adding chemicals, or increasing water temperature, do not specifically address the mechanism of air contact or do not enhance the aeration process as effectively as the packing and counter current flow strategy.