Scenario-Based LCA of Kitchen Waste Management Incorporating Transport Logistics: A Case Study of Aya Town, Japan

Kitchen waste management strongly affects greenhouse gas (GHG) emissions, especially in small municipalities with limited treatment options. This study assessed alternative strategies for Aya Town, Japan, by integrating life cycle assessment (LCA) with Geographical Information System (GIS)-based transport analysis. Six scenarios were designed, ranging from mandatory composting with frequent collection to full incineration at a regional waste-to-energy (WtE) facility. Emissions were estimated from transport, composting, and incineration processes, with sensitivity tests on composting electricity use (20, 50, and 90 kWh per ton) and WtE efficiency (15%, 17.9%, 20%, and 25%). The results showed that reducing collection frequency lowered emissions by about 9% relative to the current system, while decreasing composting participation further reduced emissions. Full incineration yielded the lowest emissions, whereas sensitivity analyses confirmed that facility parameters influenced absolute values but not the relative ranking of scenarios. These findings emphasize the importance of transport logistics, participation rates, and infrastructural context. High-quality compost may justify limited voluntary composting; however, WtE incineration remains the most robust option for climate mitigation in Japan’s incineration-based waste management system.