Aerobic treatment is a biological wastewater treatment process that takes place in the presence of oxygen. Aerobic biomass converts organics in the wastewater into carbon dioxide and new biomass.

Aerobic treatment technologies can act as stand-alone systems for treating raw wastewater, or can be used to polish anaerobically pretreated wastewater to further remove biochemical oxygen demand (BOD) and total suspended solids (TSS). Aerobic technologies can also be used specifically as a biological nutrient removal system (BNR) to remove nitrogen and phosphorus.