Life Cycle and Economic Assessment of Anaerobic Co-digestion of Dairy Manure and Food Waste

Abstract A comprehensive life cycle and financial analysis was conducted to evaluate the environmental and economic performance of an anaerobic co-digestion system for dairy manure and food wastes versus a control system that anaerobically digests dairy manure but landfills food wastes. The environmental impacts of co-digestion are lower than the control system for global warming (66.95%), water eutrophication (18.88%), and smog emission (68.93%), but higher for air acidification (39.38%). Co-digestion results in a net energy ratio that is 1.67 times higher than the control system. An economic analysis revealed that co-digestion is more profitable, as the calculated 25-year net value of over $8.4 million is far superior to the -$7.5 million for the control system. Considering both environmental impacts and economic indicators, manure and food waste co-digestion is a preferable solution for waste management and bioenergy production.