Comportamento hidrodinâmico de um reator anaeróbico de lodo fluidizado (RALF) em escala plena tratando esgotos sanitários

Abstract

It was used as an object of study the RALF reactor of the UASB type, full scale (2000 m3) treating domestic sewage with theoretical HRT of 8 h real TDH approximately 5 h, where the average flow measured during tests was 90 L/s. Were evaluated in the reactor dynamic and hydrodynamic behavior, anomalies arising from the hydrodynamic behavior and the mass recovery in the assay. It adopted the pulse type of stimulus-response method with Rhodamine WT tracer for testing. 42 samples were collected over a period of approximately 24 h. The readings of the samples were made in fluorescence spectrophotometer provided the luminescence of each sample. For the concentration of the luminance values were converted using equations obtained in standard Rhodamine WT curve. Varying the concentration of the tracer in the effluent was adjusted by the theoretical mathematical models of small and large dispersion and reactors in series. The actual HDT obtained was anticipation 2.8 h which represents 35% of theoretical THD. The RTD curve indicates the presence of hydrodynamic anomalies, it is possible to observe the sharp peak output tracer and long tail appearance at the end of the curve obtained with the hydrodynamic test data. The anticipation of the peak shows the presence of hydraulic short circuits and preferred paths in the reactor. It was found for the N value of 1.4, this value approaches 1, and according to literature values near 1 fit to the perfect mixing type flow. The N-CSTR model had the best fit with mathematical correlation (r2) of 0.959 indicating behavior that tend to the perfect blend of style in the reactor. During the test were measured cyclically-flow with peaks between 52 L/s and 103 L / s to analyze the fluid flow is observed similar behavior to the perfect blend of reactor. In the analysis of hydrodynamic anomalies it was featured in approximately 663 m3 of dead volume. It was also observed hydraulic short-circuiting, because the value of 0.125 is obtained below the minimum value 0.3 used as a parameter for evaluating the presence of hydraulic short circuit. The mass recovery tracer, Rhodamine WT, was 78% lower than expected getting it was above 85%.