In activated sludge treatment, how must microorganisms be maintained for effective treatment?

In activated sludge treatment, microorganisms must be maintained in suspension to ensure effective treatment. This method relies on a diverse community of microorganisms that are kept mixed with wastewater, allowing them to actively metabolize organic matter and break down pollutants present in the water.

Maintaining microorganisms in suspension enhances their contact with the contaminants in the wastewater, leading to more effective degradation of organic compounds. The aeration process not only provides oxygen for aerobic microorganisms but also keeps them suspended in the mixed liquor, which is critical for optimal biological activity.

If microorganisms were allowed to settle out or be removed through sedimentation or filtration, their ability to treat the wastewater would be significantly compromised, as the concentration of active microbes would diminish, resulting in reduced treatment efficiency. Thus, suspending the microorganisms provides an environment where they can thrive, ensuring that wastewater is treated effectively.