THE EFFECT OF CO-DIGESTION ON BIOGAS PRODUCTION WITH Bidens pilosa L. AND POULTRY MANURE THROUGH ANAEROBIC DIGESTION

Abstract

Biogas is an eco-friendly renewable energy source through the anaerobic digestion of organic waste materials. In this study, biogas production from co-digestion of Bidens pilosa(BP) and poultry Manure (PM) in five mix ratios (100%BP, 75%BP:25%PM, 50%BP:50%PM, 25%BP:75%PM and 100%PM) were evaluated under at 38ºC using a batch mode digester over 21 days of fermentation. In all treatments, physico-chemical parameters such as pH, total solid, volatile solid, moisture content, organic carbon, total nitrogen and carbon to nitrogen ratio were measured before and after anaerobic digestion. The daily biogas production was subsequently measured by the water displacement method for 21 days. The pH values of all substrates increased after anaerobic fermentation. The highest pH value after anaerobic digestion was recorded at 50% BP:50%PM. The highest moisture content before anaerobic fermentation (64.00%) was observed at 100%BP, whereas the lowest (59.67%) moisture content was observed from 100%of PM. After aerobic digestion, the highest (76.05%) %MC was observed from 25%BP:75% PM and the lowest (70.65%) was record from 100%of BP. The highest value of TS (86.88%) was observed in the mixed ratio of 75%BP with 25%PM before anaerobic fermentation. Whereas the lowest value (80.33%) was recorded in the treatment of 100% PM. The maximum % of carbon was recorded in a digester of 100%BP, whereas the lowest value was observed in the treatment of 100%PM. The highest % of carbon reduction was noticed in the 25%BP:75% PM mixed substrate ratio. In this study, the highest total nitrogen was recorded (1.907%) in the mixed substrate combination of 25%BP: 75%PM before anaerobic digestion. All measured physico-chemical parameters of each substrate were significantly varied between before and after AD, p<0.05%.Gas production was noticed in all of the substrate types from the first day of digestion and became zero on the 21 day in all substrates. Biogas yield was found to be higher when the two substrates were co-digested than when digested alone. Assessment of cumulative biogas production revealed that a substrate with a mixed ratio of 25% of Bidens pilosa L and 75% poultry manure showed the highest biogas production (1081.7mL), suggesting this mixed ratio of the two substrates was the optimal mix. Overall results indicate that the increment in biogas yields and VS and TS reduction could be enhanced when poultry manure and Bidens pilosa L. are co-digested.