How does an activated sludge system primarily remove waste from wastewater?

The activated sludge system primarily removes waste from wastewater through biological treatment. In this process, microorganisms, particularly bacteria, are utilized to break down organic matter in the wastewater, effectively treating it by degrading pollutants and converting them into biomass.

During the operation of an activated sludge system, wastewater is aerated in a reactor where it is mixed with a population of these microorganisms. The aeration promotes the growth and activity of the bacteria, which feed on the organic pollutants present. As the microorganisms consume the waste, they multiply and form flocs, which are clusters of bacteria and other particles.

After this biological treatment phase, the mixture is often moved to a settling tank or clarifier, where the biomass can settle out of the treated water. This allows for further purification as the treated water is separated from the sludge, which can be recycled back into the system or discarded if necessary.

In contrast, physical filtration typically involves removing solids by passing wastewater through screens or filters, which doesn’t address the degradation of organic matter. Chemical treatment would involve the use of chemicals to alter the properties of the wastewater or to disinfect it, which is not characteristic of the activated sludge process. Thermal processing involves using heat to treat wastewater, which is not a method used in activated sludge systems