Anaerobic Co-digestion of Press mud and Molasses-based Distillery Wastewater for Enhanced Biogas Production

Abstract

With goals in determining the effect of diluting the distillery wastewater (DWW) and of varying the amount of DWW and press mud (PM), anaerobic co-digestion study was carried out at mesophilic condition in a 2-L Erlenmeyer flask, with a working volume of 800 mL for Batch 1 and 1500 mL for Batch 2 experiments. For Batch 1, two different ratios of DWW and tap water, with 2:3 and 3:2, were used to assess the effect of dilution on the methane yield, where same volumetric amount of PM was added. For Batch 2, following ratio of PM and DWW were used: a) 1:0, b) 1:1, c) 1:1, d) 2:1, and e) 1:2. All samples had the same amount of inoculum, except that Batch 1 samples had bagasse. The parameters that were assessed after 42 days of digestion were: pH, COD, BOD, TSS, VS, Cu, Ca, Mg, Mn, TOC, TN, and methane yield. For the effect of dilution, a significant difference in the methane yield between samples with higher and lower dilution ratio was seen, and in the first batch, the optimal dilution ratio of DWW and H2O, with 3:2 gave higher methane yield of 78.23% (v/v). Meanwhile, optimal volumetric ratio of DWW and PM from the Batch 2 experiments, with value of 1:2, gave the highest methane yield of 79.43% (v/v).