Effect of the pH influent conditions in fixed-film reactors for anaerobic thermophilic treatment of wine-distillery wastewater

In anaerobic treatments, the pH conditions affect the efficacy and operation of the process. The main purpose of this research is to compare the effect of the pH influent on the performance of a high rate technology at laboratory scale, upflow anaerobic fixed-film reactor, treating distillery wastewater (wine vinasses) in thermophilic conditions. The results obtained shown that the pH influent influences the performance of the biodegradation process: the depurative efficiency is higher for the operation with alkaline influent. The operation with acid influent allows us to operate at organic loading rates (OLR) around 5.6 kgCOD/m³/d (hydraulic retention time: 1.5 days), maintaining total Chemical Oxygen Demand removals (COD_r) of 77.2%; the operation with alkaline influent allows total COD_r of 76.8% working at OLR around 10.5 kgCOD/m³/d. The greatest efficiency of substrate removal was 87.5% for OLR 3.2 kgCOD/m³/d and hydraulic retention time of 4.0 days operating with alkaline influent. Therefore, the operation with alkaline influent implicates senior levels of purifying efficiency for similar organic load rate.