Análise cinética de um reator anaeróbio-aeróbio de leito fixo com recirculação da fase líquida tratando esgoto sanitário

Abstract

Brazil presents a considerable deficit in relation to the treatment of effluents, from this perspective is of extreme importance the studies that aim at the modeling of treatment units. This study was based on data from the Magassy (2017) reactor, which used an CAAFBR (Combined Anaerobic-Aerobic Fixed Bed Reactor) with liquid phase recirculation treating sanitary sewage. The unit operated with 8h hydraulic detention (𝜃ℎ) and with three values for recirculation ratio (𝑟= 0, 1 e 2). Each kinetic estimation was related to two ideal models: ideal tubular and perfect mixture. For each recirculation ratio, two mass balances were performed, totaling six estimated kinetic constants (𝑘) in total. All the balance sheets considered that the degradation process followed first order kinetics. It was adopted the kinetic value that best represented each ideal flow model. The estimation of the kinetic constant for the ideal tubular model or pug-flow, presented a reaction rate for the removal of organic matter from 0,271 h-1, without recirculation of the liquid phase. The perfect mixture model resulted in 𝑘= 1.477 h-1 for 𝑟= 2. Considering the literature, the results showed that the CAAFBR presents satisfactory kinetic values for degradation of organic matter, it was also possible to observe that the recirculation ratio does not change the kinetics in the tubular model, but for perfect mixing the recirculation promotes a significant increase in the velocity of degradation of organic matter.