What is the typical oxygen rate in an activated sludge system?

In an activated sludge system, the typical dissolved oxygen level required for effective microbial activity and optimal treatment of wastewater generally falls within the range of 2-4 mg/L. This level of oxygen supports the survival and metabolism of the microorganisms that are critical for the aerobic biological treatment processes.

Maintaining dissolved oxygen within this range is essential for completing the biological decomposition of organic matter, as it allows the microorganisms to efficiently oxidize organic materials in the presence of oxygen. If the dissolved oxygen level is too low, the microbes may not be able to perform at their best, leading to incomplete treatment and the potential for odors or other issues. Conversely, excessively high levels of oxygen can lead to increased energy costs without additional benefits to the treatment process.

This optimal oxygen range is supported by various operational guidelines and standards in wastewater treatment, ensuring that the system operates efficiently while maintaining the health of the microbial population.