What does the presence of white pillowing foam on an aeration tank indicate?

The presence of white pillowing foam on an aeration tank typically indicates that the aeration process is underloaded organically. This phenomenon occurs when there is insufficient organic material in the tank for the microorganisms to consume. As a result, the microbial population can become excessive relative to the available food supply, leading to increased foam formation. This foam can be indicative of an imbalance in the aeration tank where the amount of organic matter is not sufficient to support the microbial activity effectively.

In contrast, overloads—either hydraulic or organic—would generally manifest differently, such as through the presence of different types of foam, changes in water clarity, or operational disturbances. Understanding the implications of white pillowing foam is essential for maintaining the efficiency of the aeration tank and ensuring proper treatment of wastewater.