Estimación del Coeficiente de Transferencia de Masa (KLa) y los parámetros cinéticos empleando la metodología de respirometría en un sistema de lodos activados con burbujas finas

Abstract

Improving activated sludge systems (CAS) for wastewater treatment is a need that has been reflected in recent years. One of the main limitations of the CAS are the high energy consumption associated with mechanical aeration, being between 40-90% of the total energy consumption of the system. For this reason, the objective of this study was to evaluate the influence of fine bubble aeration (BF) on mass transfer and growth rate in a laboratory-scale activated sludge system. The results showed that the mass transfer coefficient (Kla) was much higher in the system with BF (0.0283 s-1), with respect to the system using conventional aeration (0.0111 s-1) indicating an improvement in O2 transfer. Furthermore, based on the literature and the Kla obtained for the BF system, they were classified as Microbubbles (MB). On the other hand, microbial growth showed a significant increase using the MB system umax = 6,789 d-1, indicating the influence of oxygen transfer on the growth rate of microorganisms. In addition, the simulation of the system used, the Monod kinetics, showed a low influence of the affinity coefficient (Ks) on the speed of substrate consumption and also a higher speed of substrate consumption in the MB system with respect to conventional aeration. . The MB system also showed a greater capacity to treat high concentrations of COD in less time (2.3 Kg COD / m3 in 2 hours) compared to the conventional system. Finally, the microbiology associated with the system presented different microorganisms such as protozoa, rotifers and the absence of filamentous bacteria, which indicates a good functioning of the activated sludge system. These results show the importance and influence of mass transfer on the kinetic parameters and consequently on the behavior of the reactor, guaranteeing the removal of pollutants from the waste water in less time and reducing the energy cost associated with conventional aeration.