A system is disclosed herein for treating wastewater liquid by utilizing
aerobic biological species. The contaminated wastewater stream is
pretreated in a dissolved air flotation system to remove suspended solid
waste, including large particles such as fats, grease, and physically
emulsified oils. The purified wastewater containing dissolved waste is
thereafter oxygenated and further decontaminated in a bioreactor tank.
Biological species in the bioreactor tank consume oxygen and perform
bodily functions that converts dissolved waste into easily removable
carbon dioxide and suspend solids. Oxygen consumed by the biological
species is replenished by pumping the wastewater though a liquid-oxygen
mixer. A controller regulates the speed of the pump based on real-time
oxygen concentration measurements provided by a corresponding oxygen
probe disposed within the wastewater in the bioreactor tank.