What is the primary role of activated sludge in waste water treatment?

Activated sludge plays a critical role in the biological treatment of wastewater by removing dissolved and suspended solids. This process primarily occurs through the action of microorganisms present in the activated sludge, which consume organic matter in the wastewater. As they metabolize these compounds, the microorganisms contribute to the reduction of pollutants, effectively improving water quality.

The microorganisms thrive in aerated conditions, allowing them to break down organic materials into simpler substances. This not only removes harmful contaminants but also promotes the growth of more microorganisms, facilitating a continuous cycle of treatment. The result is cleaner effluent that is safer for discharge into the environment, or for potential reuse.

The other options, while related to water treatment, do not capture the primary function of activated sludge. For example, increasing the pH is not a direct role of activated sludge; rather, pH adjustments are managed through other chemical processes. Similarly, while enhanced sedimentation rates and stabilization of organics can be outcomes of a well-functioning activated sludge system, these are secondary benefits of its primary function of removing solids.