Decarbonizing Food Waste Treatment through Anaerobic Codigestion with Yard Waste: Energy, Engineering, Economic, and Environmental Aspects

This study presents the design and analysis of an anaerobiccodigestion(AcD) system to replace the existing composting system for food waste(FW) and yard waste (YW) treatment on a university campus. By combinationof kinetic models, anaerobic degradability analysis, cost analysis,and life cycle assessment (LCA), a comprehensive energy, engineering,economic, and environmental approach is applied to achieve FW decarbonization.The optimal AcD ratio of FW:YW (3:1) demonstrates a CH4 production rate of 38.2 & PLUSMN; 0.7 mL/g VS/day, with a biomethanationpotential of 0.97 and sludge activity of 100%. The economic analysisreveals a discounted payback period of approximately 2.6 years overa 10 year project lifetime, demonstrating the feasibility and financialviability of the AcD system. Furthermore, the LCA comparison betweenAcD and composting shows a significant carbon emissions reductionof approximately 68% (& SIM;146 kg CO2-eq/t-FW lower)for AcD, resulting in an annual reduction of 32 tonnes of CO2-eq if implemented for the total FW production (219 tonnes per year)on the campus. Lastly, the study proposes potential pathways for achievingcarbon neutrality in decentralized AcD plants, providing directionsfor future research.