Treatment of Swine Wastewater in Anaerobic Sequencing Batch Reactors in Series Followed by Polishing Ponds

Abstract

In this study, two anaerobic sequencing batch reactors (ASBR) installed in series were evaluated in pilot-scale testing (volumes of 280 L and 140 L, respectively) for the treatment of swine wastewater with total solids suspended (TSS) around 10,000 mg/L. The organic loading rates (OLR) applied on the first ASBR varied from 4.43 to 12.75 g total COD per (L d). For the post-treatment of the effluent generated in the ASBR, two polishing ponds were used (1000 L volume each) in series. The mean removal efficiencies of total chemical oxygen demand (COD) and of TSS varied from 53 to 86% and from 56 to 85%, respectively, in the anaerobic treatment system composed by the RSBAn. The volumetric methane production of the anaerobic treatment system with the ASBR varied from 0.628 to 0.796 m3/(m3d). 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. The mean removal efficiencies of total Kjeldahl nitrogen (TKN) and total phosphorus (total-P) varied from 30 to 82% and 42 to 100%, respectively, in the anaerobic treatment system with the ASBR following by the polishing ponds. The use of the polishing ponds in series has allowed the maintenance of mean removal efficiencies above 80% for Zn and 76% for Cu. The number of fecal coliforms was reduced to 8x103 MPN/100 mL.