Impacto do fenol no desempenho e estabilidade de um reator de lodo granular aeróbio

Abstract

This work evaluated the impact of phenol on the performance and stability of an aerobic granular sludge reactor operated in sequencing batch mode with alternating anaerobicaerobic conditions for combined organic matter, nitrogen and phosphorus removal. The reactor was fed with synthetic wastewater whose phenol concentration was gradually increased from 2 to 200 mg.L-1 , while the other carbon source (acetate) was reduced. Up to 20 mg.L-1 of phenol, the mean COD removal was above 90%, while the removal of ammonium, phosphorus and phenol was approximately 100%. The incorporation of higher concentrations of phenol into the influent associated with problems in reactor maintenance (e.g., sludge age control) affected the activity of polyphosphate-accumulating organisms and nitrifiers, leading to a drastic reduction in phosphorus and ammonium removal, in addition to partial nitrification. Although the overall COD removal was not affected by the addition of phenol, most of it was removed in the aeration phase of the cycle and no longer anaerobically during feeding, especially at 200 mg.L-1 of phenol, which led to proliferation of filamentous organisms that changed the characteristics of granular biomass.