Anaerobic Co-Digestion of Cow Manure and Palm Oil Mill Effluent (POME): Assessment of Methane Production and Biodegradation Efficiency

The performance of anaerobic co-digestion of cow manure and POME was evaluated. The anaerobic composting process was carried out by using semi-continuous reactors under the mesophilic condition (35 ± 1℃). The addition of POME to the on-going anaerobic composting of cow manure was applied stepwise within a cycle of HRT (20 days). Results showed that the anaerobic co-digestion reactor could produce methane at about six times higher (7.2 L CH4) than the control reactor (1.3 L CH4). An increasing of POME loaded to the on-going anaerobic composting cow manure culture (4% to 64%) did not affect pH of the culture in which pH was still stable between 7.11 and 7.5. Assessment of biodegradation efficiency revealed that nitrogen removal of the anaerobic co-digestion reactor was six times higher (21%) than the nitrogen removal of the control reactor (3.4%). This suggested that the anaerobic co-digestion reactor performed sufficiently well in which no organic acid as well as ammonia accumulated in the reactor that could be effective to decompose the organic matters.

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

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).

Effect Of Co-Digestion Of Source Separated Organics And Manure On Methane Production

Anaerobic co-digestion (AcoD) is more advantageous than conventional mono-digestion, because of higher gas production rate. This study was aimed to study the effect of mixture ratio in codigestion of manure and source separated organics (SSO) in mesophilic condition. Manure and SSO at different mixture ratios of 9:1, 7:3, 5:5, 3:7, and 1:9 on a volumetric basis were used to determine the effect of the mixture ratios on methane production in biomethane potential assay (BMP). Results showed that co-digestion of SSO and manure at the ratio of 1:9 (V/V) resulted in the highest biomethane production rate of 46 mL CH4 /day. In comparison, the maximum methane production rate for anaerobic digestion of manure alone was 43 mL CH4 /day. When manure is mixed with SSO at a ratio of 5:5, about 15% higher cumulative methane production has been achieved. This research also verified the advantages of co-digestion over mono-digestion. Keywords: Anaerobic Digestion, Co-digestion, Source Separated Organics (SSO), Manure