Abstract
An experimental study has been conducted to analyze an aerobic wastewater treatment using a draft tube air-lift reactor suspended with biologically active carbon particles. The liquid circulation rate and the volumetric gas-liquid mass transfer coefficient were measured under suspending fresh activated carbon particles. Effects of initial substrate concentration, dissolved oxygen concentration and reaction temperature upon the substrate removal rate were measured under the liquid batch operation. The experiments for liquid continuous operation were also performed to obtain conversion versus space time data.
The substrate removal rate is found to obey 0-th order kinetics for the substrate concentration greater than 150 mg·l-1 and Monod kinetics for the substrate concentration smaller than 150 mg ·l-1. In the 0-th order kinetics region, the reaction rate increases with the dissolved oxygen concentration in proportion to the power of 0.2 for the oxygen concentration and the apparent activation energy for the reaction is found to be 33.5 kJ·mol-1. The substrate conversion data for the liquid continuous operation can be predicted well by the model analysis assuming the liquid flow in the draft tube reactor to be a completely mixed flow.
