In wastewater treatment, what is the role of microorganisms?

Microorganisms play a crucial role in wastewater treatment primarily by breaking down organic matter and pollutants present in the wastewater. This biological process is essential for reducing the levels of harmful substances, making the water safer for discharge into the environment or for reuse. The microorganisms utilize the organic materials as a food source, converting them into simpler, less harmful compounds.

This microbial action not only helps in degrading organic pollutants but also contributes to the overall stabilization of the wastewater, aiding in the reduction of biochemical oxygen demand (BOD) levels. A healthy population of microorganisms is vital for the effective operation of biological treatment processes, such as activated sludge systems and biofilters, which rely on these organisms to treat waste.

In contrast, filtering out solid waste is primarily the function of physical processes in the treatment system, while aeration primarily serves to enhance the activity of these microorganisms by supplying them with oxygen. Chemical reactions for disinfection, such as chlorination or ozonation, are distinctly separate processes from the biological digestion performed by microorganisms. Thus, the role of microorganisms in breaking down organic matter and pollutants is fundamental and essential within the wastewater treatment process.