What type of system uses microorganisms to treat wastewater?

Biological treatment systems utilize microorganisms to break down organic matter in wastewater. This process is essential for removing pollutants before the water is released back into the environment or further treated. In these systems, bacteria and other microorganisms consume organic matter as their food source, leading to the degradation of contaminants.

The use of biological treatment is based on the natural processes of decomposition, making it a cost-effective and efficient method for reducing biochemical oxygen demand (BOD) and other harmful substances in wastewater. Common methods of biological treatment include activated sludge systems, trickling filters, and anaerobic digesters, all of which harness the abilities of these microorganisms.

In contrast, mechanical treatment systems primarily involve physical processes to remove solids from wastewater, such as screening and sedimentation. Chemical treatment systems rely on the addition of chemicals to facilitate the removal of contaminants through processes like coagulation and disinfection. Physical treatment systems, similar to mechanical, involve processes that do not biologically alter the water's composition through biological reactions. Therefore, the distinctive feature of biological treatment systems is their reliance on living organisms to achieve wastewater treatment goals effectively.