Which type of air stripper utilizes diffused aeration?

The type of air stripper that utilizes diffused aeration is primarily associated with structured systems that involve the introduction of air in a dispersed manner. Specifically, the coke tray aerator is designed to allow air to pass through multiple trays or layers, facilitating efficient mass transfer of volatile compounds from the liquid phase into the air phase. This is achieved by diffusing the air into small bubbles, which enhances the surface area for gas exchange and improves the effectiveness of removing contaminants from the wastewater.

In contrast, the countercurrent packed tower and crossflow tower typically use different mechanisms for air and liquid interaction, where the airflow direction is designed to optimize contact without the use of diffused aeration methods. Although "diffused aeration" is mentioned as a choice, it doesn't refer to an aerator type in the context of this question but rather to the method of air introduction. Therefore, the coke tray aerator stands out as the appropriate choice due to its specific design that incorporates diffused aeration techniques to maximize the removal of volatile substances from wastewater.