Biological wastewater treatment utilizes bacteria populations such as protozoa and other microbes to degrade organic contaminants in the wastewater. There are three (3) major biological processes used for wastewater treatment :
1. Aerobic for treatment process requiring oxygen.
2. Anoxic for treatment process with absence of free oxygen, but presence of bound oxygen such as nitrite or nitrate.
3. Anaerobic for treatment process with a total absence of free oxygen (O2) or bound oxygen (NO2, NO3).
Each process is further subdivided into Suspended Growth Systems or Attached Growth Systems.
