Combined Treatment of Mezcal Vinasses by Ozonation and Activated Sludge

In Mexico, mezcal production generates huge amounts of vinasses (mezcal vinasses) that cause negative environmental impacts. Thus, mezcal vinasses treatment is necessary before discharging to water bodies. Although there is no information for mezcal vinasses, similar effluents have been treated by biological processes (i.e., anaerobic and aerobic), usually complemented by oxidative chemical pretreatments (ozonation) and physicochemical methods. In this work, mezcal vinasses were first ozonated and then subjected to batch aerobic biological degradation. In the ozonation stage, organic matter removals were 4.5 to 11 % as COD, whereas the removal of aromatic compounds and phenols was 16 to 32 % and 48 to 83 %, respectively. In aerobic post-treatment, COD depletions up to 85% were achieved; removals in ozone-pretreated vinasses were higher (80–85 %) than those in raw vinasse (69 %). It seems that ozonation preferentially attacked the recalcitrant fraction of organic matter present in the vinasses and increased its aerobic biodegradability.