ENHANCEMENT OF THE ANAEROBIC-DIGESTION OF WINE DISTILLERY WASTE-WATER BY THE REMOVAL OF PHENOLIC INHIBITORS

Wine-distillery wastewater has a high organic pollutant load (40 g COD/litre) which includes various phenolic compounds, the major ones being gallic acid, p-coumaric acid and gentisic acid This feature makes it difficult to treat this wastewater anaerobically without a prior dilution of the wastewater. Partial removal of some of the organic matter and phenolic compounds by aerobic pretreatment with Geotrichum candidum is described in this study. This method provides a partially purified effluent that is more rapidly anaerobically degraded than the original wine-distillery wastewater for the same COD-loading level. The anaerobic bioreactor contained a suspension of micronized clay (saponite) to which the microorganisms responsible for the process adhered Assuming that the overall anaerobic digestion process follows first-order kinetics, the specific rate constant, K0, was obtained under various conditions. In contrast to the anaerobic digestion of unmodified wine-distillery wastewater, the kinetic constants of the anaerobic digestion of aerobically pretreated wine-distillery wastewater were virtually constant over the COD range used (1.0-6.7 g/litre).