Abstract

FERRARA-GINER, Griselda  and  RAMIREZ, Armando. Settleability analisys of biological sludges produced in SBR during effluent biological reactor denitrification. Rev. Fac. Ing. UCV [online]. 2013, vol.28, n.1, pp.37-44. ISSN 0798-4065.

The sedimentation behavior of mixed liquor sludge of a sequential batch reactor (SBR), operated to laboratory scale (10 liters capacity) under anoxic conditions in order to denitrify a substrate integrated by the effluent of a attached growth bioreactor feeded with a synthetic residual liquid. The denitrifyng process was operated by 6 hours cycles and under three different conditions of volumetric fraction (50%, 20% y 0%) required to balance the organic carbon content. The operational sequence consisted of the following phases: filled, 15 min; anoxic reaction, 4 hours and 30 min; "polished" (aireation/agitation), 15 min; sedimentation, 45 min; decant, 15 min. Four experiments were done for each supplementary carbon fraction and the sedimentation rate was measured in a 1 liter graduated cylinder. This permitted to evaluate the sludge sedimentation behaviour: the sludge volumetric index (IVL), sedimentation rate at the interphase (r_s) and the critical time (t_c).The sludge characteristics obtained indicate that the IVL values showed an excellent sedimentation behaviour when the volumetric fraction used was 20% and very good for 50% and 0%. The sedimentation rate reached relatively high values and the critical time values were similar to other previous experiments.

Keywords : Biological reactors; Denitrification; Sludge behaviour; Sequential batch reactors; Wastewater treatment.

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