HYDRODYNAMIC CHARACTERISTICS OF A STRUCTURED BED REACTOR SUBJECTED TO RECIRCULATION AND INTERMITTENT AERATION (SBRRIA)

ABSTRACT This work aimed at evaluating the effect of recirculation ratio on the degree of mixing in the flow of a structured bed reactor. Stimulus-response assays were carried out with hydraulic retention times of 6 h and 12 h, subjected to recirculation ratios of 0, 1, 2, 3, and 4. The assays were undertaken with dextran blue as a tracer and without aeration. The results fitted a compartment model, allowing the determination of the mixed-flow and plug-flow volumes inside the reactor. The model application showed that recirculation ratios between 1 and 3 do not increase the mixed-flow volume of the reactor. Higher mixed-flow volumes were obtained at recirculation rates higher than 4 for both 6 h and 12 h of hydraulic retention times. The results obtained in this research are important for future applications of this reactor configuration, promoting a mixed flow in the reactor with a minimum recirculation ratio.