Hydrodynamic Performance of an Expanded Granular Sludge Bed Reactor for the Removal of Organic Matter

摘要

Expanded granular sludge bed (EGSB) reactors are classified as third-generation anaerobic systems. They operate using a fluidized bed, which allows an increase in organic load, a decrease in hydraulic retention times, an increase in cell retention times, and higher treatment efficiencies compared with upflow anaerobic sludge blanket reactors. In this research, two EGSB reactors were employed and the upflow velocity, temperature, and organic load were varied. Reactors were operated with synthetic wastewater using a biodegradable substrate (dextrose). The residence time distribution of the reactor was analyzed using tracer tests. A temperature of 35 degrees C influenced bacterial degradation kinetics, allowing an increase in the percentage of organic matter removal. At ambient temperature, a removal of 89.49% was obtained with an organic loading rate (OLR) of 3.39 kg/m(3).day, while at 35 degrees C the best removal was 93.98% with a higher OLR (4.23 kg/m(3).day). Recirculation in reactors improved fluidization of the bed and mixing, favoring granulation of biomass and allowing operation of reactors under a fully mixed tank model. Biomass granulation improved settleability and made the process more efficient. It was found that an upflow velocity of 6 m/h at ambient temperature produced a high removal of chemical oxygen demand (96.83%).