A Mini-Review on Hydrodynamics of Airlift Bioreactors with Net Draft Tube and Their Application in Pollutant Biodegradation

Mixing and oxygenation in tower-type bioreactors are typically driven by gas movement and as a result, these bioreactors have lower shear force as well as lower power requirement than other mechanically diven ones. This paper reviews the hydrodynamic charactersitisc of a special tower-type reactor, the airlift reactor with net draft tube (ALR-nd), and a comparison of these charactersitics was done between this modified airlift reactor with bubble column reactor (BCR) and conventional airlift reactor (ALR). The reviewed results showed that the presence of the net draft tube resulted in better liquid mixing and larger gas-liquid interfacial areas and therefore produces higher mixing efficiency and oxygen transport capability in comparison with that achievable by BCR and ALR. Also a brief review is done on the applications of ailift reactor with net draft tube for different pollutants biodegradation. The high biodegradation rates achieved and their good performance in this area made them highly potential for industrial use and a good choice for even highly toxic wastewater treatment.

Keywords:

Airlift reactor , Net draft tube , Hydrodynamic characteristics , Biodegradation , Bubble column