ANAEROBIC-AEROBIC TREATMENT OF SWINE WASTEWATER IN UASB AND BATCH REACTORS IN SERIES

In this work it was evaluated the performance of two systems of swine wastewater treatment consisting of two- stage upflow anaerobic sludge blanket ( UASB) reactors, with and without post- treatment in sequencing batch reactor ( SBR), fed continuously, with aerobic phase. The UASB reactors in the first stage had 908 L in the sets I and II, and in the second stage 350 and 188 L, respectively. In the set II the post- treatment was performed in a SBR of 3,000 L. The hydraulic detention times in the anaerobic treatment systems were 100, 75 and 58 h in the set I; 87, 65 and 51 h in the set II; and 240 and 180 h in the SBR. The volumetric organic load applied in the first stage UASB reactors ranged from 6.9 to 12.6 g total COD ( L d)(-1)in the set I and 7.5 to 9.8 g total COD ( L d)(-1) in the set II. The average removal efficiencies of total COD, total phosphorus (Ptotal),andKjeldahlandorganicnitrogen(KN and Norg) in the anaerobic treatment systems were similar and reached maximum values of 97%, 64%, 68%, and 98%. In the SBR, the removal efficiencies of total COD and thermotolerant coliforms were up to 62 and 92% resulting, respectively, in effluent concentrations of 135 mg L-1 and 2x104MPN ( 100 mL)- (-1). For Ptotal, total nitrogen ( TN) and Norg, the average removal efficiencies in the SBR were up to 58, 25 and 73%, respectively.