In the activated sludge process, what is the target concentration of DO?

In the activated sludge process, maintaining an appropriate level of dissolved oxygen (DO) is crucial for the effective treatment of wastewater. The target concentration of DO is set at a level that ensures sufficient oxygen is available for the bacteria that break down organic matter during the treatment process.

A concentration of 2.0 mg/L provides a balanced environment that supports the metabolic needs of the microorganisms responsible for biodegradation. This level encourages optimal activity without wasting energy or resources on unnecessary aeration, which can occur at higher concentrations.

Lower concentrations, such as 1.0 mg/L, might not provide enough oxygen for the bacteria to thrive, leading to suboptimal treatment performance. Similarly, while higher concentrations like 3.0 mg/L or 5.0 mg/L could support the bacteria, they can also lead to issues like increased operational costs and potential difficulties in maintaining the aeration system. Therefore, 2.0 mg/L is considered an efficient target for the activated sludge process, ensuring effective wastewater treatment while maintaining cost efficiency.