Performance improvement of an integrated anaerobic-aerobic hybrid reactor for the treatment of swine wastewater

Abstract

In this study, performance of a lab-scale anaerobic-aerobic hybrid reactor, treating swine wastewater was evaluated under three different organic loading rates (OLR). The operating of integral hybrid system consisted of two experimental sections: first, an UASB section, and second, a UASB section + aerobic packed-bed with polyethylene rings. During the reactor operation, three assays of SMA were carried out and according to these results (0.26, 0.32 and 0.81 kg COD-CH4/kg VSS·d), the OLR was gradually step increased from 3.26 to 4.02 and finally 10.14 kg COD/m3·d. With this strategy, the removal efficiency of organic matter during the last operational condition increased 34.3% compared to the initial, using the SMA as a control tool. In addition, the nitrogen accumulated that could not be removed in the UASB section was treated by the aerobic packed bed, by nitrification-denitrification simultaneous achieving almost a total removal. This removal was attributed 55 ± 11% to nitrification process, 30% to denitrification and stripping were 11 ± 1%. Therefore, this anaerobic-aerobic hybrid reactor is an integral unit that allowed greater operating efficiencies than other hybrid systems that operate in two or more units, and is capable of complying with current regulations for discharge to water bodies.