Remoção simultânea de matéria orgânica, nitrogênio e fósforo em reator sequencial em batelada operado pelo regime intermitente de aeração tratando esgoto sanitário sintético

Abstract

The launching of wastewater containing nutrients, particularly nitrogen and phosphorus, causes important impacts on health and the environment, making it indispensable to incorporate the processes of removal of these compounds into the treatment systems wastewater. In the present work, different stages and operational conditions were studied to promote the joint removal of organic matter, nitrogen and phosphorus in a sequencing batch reactor (SBR), operated in alternating regime, at laboratory scale, fed with synthetic effluent containing TKN in the average concentration of 53.2 mgN/L, organic matter at the concentration of 781 mg COD/L and phosphorus at the concentration of 2.3 mgP/L. In step 1, the reactor was operated in 24h cycles, under anaerobic/aerobic/anoxic regime, obtaining average efficiency of removal of organic matter and nitrogen of 56.7% and 35.1%, respectively, being maintained an average concentration of OD around 1.13 mg/L. In step 2, in which 3 operational conditions were studied, the reactor was operated in cycles of 12h, under anaerobic/aerobic/anoxic/aerobic regime, under an average concentration of OD around 1.12 mg/L. Condition 2, in which the synthetic sewage was used as a carbon exogenous source (ratio C/N equal to 5.3), presented the best cod removal efficiency (93.5 ± 3.1%), N-Total (63% ± 14.7%) and total phosphorus (83 ± 4.6%). In contrast, condition 3 presented the best rate of average efficiency of denitrification 96%, showing that the ethanol applied with ratio C/N equal to 1.25, was the most efficient exogenous source for denitrification. The results showed the feasibility of applying the RSB for joint removal of organic matter and nutrients (N and P).