Biological wastewater treatment is the process by which microorganisms, bacteria, archaea, and other microbes are used to break down and remove organic contaminants, nitrogen, and phosphorus from wastewater. It is the treatment stage that does the most fundamental work in any ETP or STP, and it operates through three distinct microbial environments: aerobic, anaerobic, and anoxic. Understanding the difference between these three conditions is not a technical luxury; it is the foundation for designing, operating, and troubleshooting any biological treatment system.
