Investigation of the effects of starting pH, mass and retention time on biogas production using poultry droppings as feedstock

Abstract

The effect of starting pH, mass and retention time on biogas production was studied using poultry droppings as the feedstock. A full factorial experiment was designed and performed with starting pH set at 5, 6, 7, 8 & 9 for feedstock mass of 100g and 200g at specific retention times. The results presented an optimal biogas yield at pH=7 with a volume of 722 and 1046cm3 while pH=5 had the least with 255 and 481 cm3 at 100g and 200g mass respectively. The starting pH, mass and retention time and the interaction of starting pH and mass had significant effect on biogas yield at 5% significance level. The R-Square value obtained from the analysis was 92.1%. Thereafter, a log-linear regression model for predicting biogas yield was generated and was found to provide adequate prediction given its MAPE value of 19.97. Keywords: Biogas Production, Mass, Poultry Droppings, Retention Time, Starting pH.