Alternative biological systems for the treatment of vinasse from wine
This work studied alternative treatment schemes for the vinasse wastewater from wine distilleries aiming at overcoming the problems caused by the high nitrogen and sulfur concentrations. A plexiglas laboratory-scale upflow anaerobic sludge blanket (UASB) reactor of 20 L volume that was operated at 45°C and hydraulic retention time 1 d, was included in all the examined systems. System 1 was the conventional UASB reactor, system 2 was the UASB reactor supplemented with iron. System 3 consisted of the UASB reactor supplemented with iron and a CSTR reactor that operated under the following conditions: Diluted Oxygen 1.2 mg/L, Hydraulic Retention Time 1 d, pH 6.7 and Temperature 45°C. System 3 aimed at converting ammonium directly to dinitrogen gas under anaerobic conditions but it needed to be preceeded by a first partial nitrification step. All systems had high COD efficiencies over 75%. Ferrous iron addition apart from enhancing the performance of systems 2 and 3, it was able to retain all sulphur content of the wastewater as ferrous sulfide stripping the biogas from hydrogen sulfide. System 3 also managed to meet its goal, since it achieved an 86% nitrogen reduction. Conclusively, system 3 seems to be a very promising environmental technology for the treatment of distillery and winery byproducts, as well as industrial wastewater with high sulfur and nitrogen content.
Keywords: anammox, ferrous iron, nitrogen reduction, UASB, vinasse