When sizing the tank for a raised filter bed in a commercial building, what is the required aeration tank size?

The required aeration tank size for a raised filter bed in a commercial building is important for proper treatment of wastewater. The correct answer is three times the daily flow because this size ensures adequate retention time for the wastewater, which is essential for effective biological treatment. A larger aeration tank allows for better aeration of the wastewater, supporting the growth of aerobic microorganisms that help break down organic material.

This sizing also accommodates fluctuations in daily flow, ensuring that the treatment process can handle peak loads without compromising efficiency. It helps maintain optimal conditions for microbial activity, which is crucial in the treatment process for commercial applications, where wastewater volumes can vary significantly throughout the day.

In comparison, options that suggest a size smaller than three times the daily flow would not provide adequate retention time or aeration capacity, which could lead to decreased treatment efficiency and potential overflow issues. A tank equal to the daily flow would be insufficient, and a size of four times the daily flow, while it would ensure sufficient treatment capacity, may be more than necessary, thereby increasing costs unnecessarily without significantly improving the treatment process.