On this study the performance of two anaerobic sequencing batch reactors (ASBR) installed in series was evaluated on a pilot-scale testing (volumes of 280 L and 140 L, respectively) for the treatment of swine wastewater with total suspended solids concentrations (TSS) around 10.000 mg L-1. For the post-treatment of the effluents from the anaerobic treatment system with ASBR, two polishing ponds were used (1.000 L of volume each) in series. The organic loading rates (OLR) applied on the first ASBR varied from 4.43 to 12.75 g totalCOD (L d)-1. The mean removal efficiencies for totalCOD and TSS varied form 52 to 86% and from 54 to 87%, respectively, on the anaerobic treating system. The volumetric methane productions on the anaerobic treating system varied from 0.628 to 0.786 m³ (m³ reactor d)-1. The use of polishing ponds in series has allowed the maintenance of mean removal efficiencies above 89% and 91% for total COD and TSS, respectively.
anaerobic digestion; organic loading rate; two stages; post-treatment
