What characterizes the activated sludge process in wastewater management?

The activated sludge process is characterized primarily by the use of aeration in a mixture of wastewater and sludge solids. This method promotes biological treatment of the wastewater by increasing the oxygen content, which encourages the growth of microorganisms that consume organic pollutants. In this process, the wastewater is mixed with a specific population of microorganisms contained in the activated sludge.

As the mixture is aerated, these microorganisms break down organic matter, effectively treating the wastewater. After aeration, the mixture is allowed to settle, separating the treated water from the settled solids, which can then be recycled back into the process. This combination of aeration and microbial action is what fundamentally defines the activated sludge process, making it efficient for reducing biochemical oxygen demand (BOD) and total suspended solids in wastewater.

In contrast, settling solids to remove pollutants primarily refers to sedimentation processes that occur after biological treatment, and while these processes are important, they do not define the activated sludge method itself. Targeting chemical pollutants is typically a characteristic of advanced treatment methods, while stabilizing organic matter using natural processes is more aligned with processes such as soil-based treatment systems or stabilization ponds, rather than the activated sludge process.