Influence of draft tube cross-sectional geometry on KLa and ε in jet loop bioreactors (JLB)

Due to their compactness, and high flexibility in operation, the new processes like jet loop bioreactors (JLB) show a large potential for high removal efficiency and significant cost reduction in particular for the biological treatment of highly polluted wastewater. The rate of oxygen delivery determines the efficiency of aerobic processes. A modified JLB with square cross-sectional draft tube was developed in this study. Experiments were performed to investigate the effects of cross-sectional geometry, liquid flow rate and gas flow rate on gas hold-up and KLa. The comparison of these parameters as well as KI.a was carried out for two cross-sectional draft tubes geometry. The results indicated that KI.a values were better by 11-13% in square draft tube. In this study, the mass transfer characteristics with the square draft tube configuration have also been studied and a model was developed for this configuration. (D) 2007 Elsevier B.V. All rights reserved.