What is the most commonly used biological treatment process for the removal of organic matter from wastewater?

The activated sludge process is the most commonly used biological treatment for the removal of organic matter from wastewater. This method involves aerating the wastewater to promote the growth of microorganisms that digest organic pollutants. The aerated mixture contains a dense population of microorganisms, which effectively break down organic material, forming flocs that can be separated from the treated water.

In contrast, trickling filters, while they are a valid treatment process, primarily involve passing wastewater over a bed of media colonized by microorganisms, allowing for biofilm development. Although effective, they are not as widely used as the activated sludge process in many municipal wastewater treatment facilities.

Sewage lagoons are more passive systems that rely on natural processes and sunlight for treatment over extended periods, making them less efficient for higher loads of organic matter compared to the activated sludge process.

Biofilters utilize similar principles as trickling filters; however, they may not always provide the same level of control over the treatment process due to the variability in the media and flow operation.

The prominence of the activated sludge process is attributed to its efficiency, scalability, and ability to handle varying loads of organic matter, making it the preferred method in most contemporary wastewater treatment facilities.