Effect of liquid flow rate and bed void fraction on the hydrodynamics and performance of a trickle-bed bioreactor

Hydrodynamics has a strong influence on substrate elimination capacity in trickle-bed bioreactors (TBB). The present study reports the influence of liquid mass flow rate and bed void fraction on the TBB liquid residence time distribution (RTD), gas-liquid pressure drop, liquid hold-up, and biofilm wetting efficiency. Most RTD are well represented by a dispersion model. It is also shown that the hydrodynamic parameters increase as superficial liquid mass flow rate increases and as bed void fraction diminishes. The TBB isopropyl alcohol (IPA) mineralization capacity reach its largest values at a bed void fraction of 0.6, and the lowest are obtained when it is 0.44, when the TBB turns anaerobic due to excessive biomass growth. Overall, it is shown that the TBB performance is strongly dependent on hydrodynamics.