Estudo teórico e experimental de um reator anaeróbio de fluxo ascendente e manta de lodo tratando águas residuárias domésticas.

Abstract

The thesis work in question had for general objective to accomplish a theoretical/experimental study to evaluate the fluid dynamic of an anaerobic reactor of ascending flow and sludge blanket (Upflow Anaerobic Sludge Blanket – UASB), treating domestic wastewater, seeking to contribute to improve the performance of the phases separation devices. For the experimental study, it was accomplished the monitorially of the operational stability and the efficiency of the reactor treatment through physical-chemical analyses from samples of its affluent and effluent, as well as, the pressure along the reactor. The results obtained experimentally proved that the reactor presented a good operational stability. The efficiency of removal organic matter was considered low (42%); while for the total solid in suspension the removal efficiency varied around 70%. The pressure values presented a decreasing linear relationship as the taken of pressure distanced itself of the digestion zone. For the numeric study, meshes were developed in the space bi and three-dimensional representative of the UASB reactor modifying the dispositions and inclinations of the reflector of gases. Different simulations were accomplished using the Ansys CFX 10.0 for different flows. The numeric results verified that the disposition and inclination of the gases diverter besides exercising great influence on the distribuition of speed in the reactor, they also affected considerably the acting of the devices of phases separation (gases diverter and three-phase separator). In relation to the mass flow, it was verified that the same one presented a relationship directly proportional with the efficiency of suspended solid retention, for the strip studied in the present work (10-4 to 0,11 kg/s). The comparative analysis of the numeric and experimental results of the pression and of the sludge concentration in the exit of the reator with inclination of the diverter returned upward they presented differences of the order of 2 kPa and of 10 mg/L, respectively, being considered satisfactory.