Reator anaeróbio-aeróbio de leito fixo em escala piloto, com recirculação da fase líquida, aplicado ao tratamento de esgoto sanitário

OLIVEIRA NETTO, A. P. (2011). Anaerobic-aerobic pilot-scale fixed-bed reactor, with recycle of the liquid phase, applied to the treatment of domestic sewage. Sao Carlos, Thesis Escola de Engenharia de Sao Carlos, Universidade de Sao Paulo. This work was based on design, technology development, scale up and performance evaluation of an up-flow combined anaerobic-aerobic fixed bed system, with recycle of the liquid phase, for treatment of domestic sewage. The pilot scale reactor was built in a fiberglass cylindrical shape with a total volume of approximately 2.5 m, aiming at the development of a system capable of operate as a single treatment unit for organic matter and nitrogen removal, with low sludge production and energy consumption by the advantages of combination of anaerobic and aerobic processes. The improved operating results were found for the condition with overall hydraulic retention time (HRT) of 12 hours and recycle ratio (r) equal to 3.0, with average removal efficiencies of COD, TKN and TSS of 92 ± 3%, 68 ± 11% and 75 ± 7%, respectively, with average effluent values of 54 ± 22 mgCOD/L, 14 ± 10 mgTKN/L and 70 ± 42 mgTSS/L. The average values of removed organic loading rate (OLR) and nitrogen volumetric loading (NVL) reached 1.06 ± 0.04 kgCOD/m.d and 0.06 ± 0.02 kgTKN/m.d for this phase. The operational stability during the stage with HRT of 12 h, the high organic matter and nitrogen removal, without addition of exogenous carbon source (electron donor) to promote the denitrification process, with no supplementation of alkalinity consumed during nitrification, and the reduced maintenance due to manufacturing technology adopted, proved the technical feasibility of the combined fixed-bed reactor as a compact unit for small communities or low inflow rates, for treatment of domestic sewage.