Which type of bacteria are primarily involved in the biological treatment of wastewater?

Heterotrophic bacteria play a crucial role in the biological treatment of wastewater because they are capable of using organic matter as their primary source of energy and carbon. In wastewater treatment systems, these bacteria break down complex organic pollutants into simpler compounds, often converting them into biomass, carbon dioxide, and other byproducts. This process is essential for reducing the organic load in wastewater and ensuring it meets regulatory standards before being released into the environment or undergoing further treatment.

In contrast, while autotrophic bacteria can utilize inorganic carbon sources (like carbon dioxide) and are important for certain processes, such as nitrification, they do not primarily target the organic pollutants typically present in wastewater. Facultative bacteria can switch between aerobic and anaerobic respiration depending on available oxygen levels, but their role is more varied and situational, often playing a secondary role in the overall treatment process. Thermophilic bacteria thrive at high temperatures and may be involved in some specialized systems but are not the primary actors in standard wastewater biological treatment. Thus, heterotrophic bacteria are recognized as the chief contributors to the effective breakdown of organic pollution in wastewater processes.