BIOGAS PRODUCTION FROM POULTRY DROPPINGS THROUGH ANAEROBIC DIGESTION

Abstract

The increasing demand for renewable energy sources highlights the need for optimizing biogas production. This study investigates the potential of poultry droppings as a substrate for biogas generation, focusing on the influence of temperature and pH variations on yield. Additionally, key bacterial species involved in the anaerobic digestion process are identified to better understand microbial contributions. Anaerobic digestion was conducted using poultry droppings over seven weeks/ retention periods using the water displacement method, while temperature and pH variations were monitored throughout the study. Bacterial species were isolated and characterized using standard microbiological techniques. Statistical analysis was performed using one-way ANOVA to determine significant differences in biogas production across retention periods, with a significance level set at p < 0.05. The highest biogas yield was recorded at week 2 (14 days) with 535.00±70.50 mL, while the lowest yield was observed at weeks 3 and 4 (21–28 days) with 0.00 mL. The highest temperature was recorded at week 6 (42 days) with 41.71±0.64°C and the lowest at week 4 (28 days) with 30.20±2.78°C. The lowest pH observed at week 2 (6.15±0.462) after digestion, indicating acidogenesis, while the pH stabilized in the later weeks. Microbial analysis revealed Bacillus subtilis (35.71%) as the most dominant bacterium, followed by Staphylococcus aureus and Escherichia coli (21.42% ) each, while Shigella species had the lowest occurrence with (7.14%). The results of this study indicate that anaerobic digestion of poultry droppings can yield significant amounts of biogas, particularly during the second week of retention. Future research should explore co-digestion strategies as well as microbial inoculation to further optimize biogas yield.