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

Abstract

This study presents the design and analysis of an anaerobic codigestion (AcD) system to replace the existing composting system for food waste (FW) and yard waste (YW) treatment on a university campus. By combination of 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 ± 0.7 mL/g VS/day, with a biomethanation potential of 0.97 and sludge activity of 100%. The economic analysis reveals a discounted payback period of approximately 2.6 years over a 10 year project lifetime, demonstrating the feasibility and financial viability of the AcD system. Furthermore, the LCA comparison between AcD and composting shows a significant carbon emissions reduction of approximately 68% (∼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 achieving carbon neutrality in decentralized AcD plants, providing directions for future research.

Role of Lignocellulosic Biomass Composition to Regulate Microbial Mutualism for Organic Mineralization and Humification during Digestate Composting

“…Food waste from households, restaurants, and food processing facilities accounts for the largest organic fraction in solid waste from the built environment. , Food waste is a major source of pollution if it is not properly managed. However, it is also a valuable resource for organic fertilizer and energy production. − In a modern circular economy, food waste is segregated and used as feedstock for anaerobic digestion to produce energy (in the form of biogas) and digestate that can be converted to soil conditioner …”

Understanding Anaerobic Co-digestion of Organic Wastes through Meta-Analysis

“…Anaerobic co-digestion (AcoD) is a widely employed strategy for managing organic waste and recovering energy. It offers several advantages over mono-digestion, such as improved digestibility, better buffering capacity, and optimal nutrient balance, all of which lead to increased process stability, higher biomethane yield, and improved digestate quality. , The effectiveness of AcoD relies on selecting co-substrates with compatible spatial and temporal availability and characteristics, which helps ensure a consistent supply of feedstock and reduces the need for storage and transport . In the wastewater and solid waste treatment sectors, AcoD has gained popularity for its role in sustainable resource recovery.…”