Using Residual Syrup to Increase Digester Gas Production

Due to economic conditions and ongoing construction projects, a fuel cell project was short of biofuel, potentially reducing the “green” nature of the project. An opportunity to increase digester gas (biogas) production while reducing disposal costs for a local soft drink supplier was identified. The residual high fructose corn syrup from the supplier was fed to a conventional anaerobic sludge digester. Biogas production increased as was expected, confirming that full conversion of the syrup to biogas is being achieved. Further analysis confirmed that the increased biogas production was not the result of increased solids fed to the digester. It is estimated that the gross benefit to the owner of the anaerobic digester is approximately 176 per ton of sugar added as syrup.