Characterizing Life Cycle GHG Emission from Trap Grease-to-Biodiesel Production Pathway

摘要

Trap grease is a mixture of fats, oils, greases (FOG), wastewater and solids that accumulate in the grease trap of restaurants and food processing facilities. The FOG in the trap grease is the major cause of sewer pipe clogging. Utilizing trap grease as a feedstock for biodiesel production is expected to be a win-win solution for both waste management and improving air quality through biofuel production. In order to confirm if this waste-to-energy practice is environmentally sustainable, this paper presents a life cycle analysis of its GHG emissions for the first time. The system boundary of this paper includes the stages of raw material acquisition, FOG separation and pre-treatment, biodiesel production, solids for anaerobic digestion, and waste disposal. It was shown that utilizing the solids in the trap grease for AD would render the production life cycle carbon-negative (-55.49 g CO_2 eq/gal biodiesel), indicating that trap grease can be a sustainable feedstock for biodiesel production.