Seasonal Variations in Biogas Production from Excreta of Monogastric Farm Animals under Tropical Climate

Abstract

The present study analysed the changes in the quantity and composition of biogas produced from the excreta of swine, rabbit and poultry during monsoon and summer seasons. The highest volume of biogas production was observed in rabbit excreta (0.0813 ± 0.0007m3), followed by poultry excreta (0.0778 ± 0.0005 m3) and swine excreta (0.0738 ± 0.0004 m3). Methane concentration was higher in biogas produced from rabbit excreta (70.96 ± 0.19) followed by that from poultry excreta (66.87 ± 0.21) and swine excreta (62.41 ± 0.20), whereas carbon dioxide concentration was highest in swine excreta (28.07 ± 0 .32) followed by rabbit excreta (24.54 ± 0.15) and poultry excreta (22.14 ± 0.14). The biogas production was significantly higher (P less than 0.01) in the summer season compared to monsoon in all three substrates. It was observed that daily mean temperature had a significant positive relationship and relative humidity had a negative relationship with the quantity of biogas produced (P less than 0.01). The gas production also had a significant positive correlation with the temperature and pH of the digesta.