Synergistic analysis of environmental and economic performance of construction waste disposal through the determination of optimal landfilling fee

The construction industry generates a substantial amount of construction waste (CW) annually, with a large share disposed of via landfilling, contributing significantly to carbon emissions (CE). Despite alternative methods, the lack of a quantitative long-term framework to balance environmental and economic goals hinders effective disposal decisions. This study develops a system dynamics model integrated with multi-objective optimization approach to assess the environmental and economic performance of CW disposal through a weighted sustainability score (WSS). Scenarios are constructed by varying the weightings of environmental and economic criteria and adjusting landfill fees from 100 yuan/ton to 500 yuan/ton in 50 yuan/ton increments. In the landfilling-only scenario, the optimal fee remains at 300 yuan/ton when the environmental weight is between 0 and 0.8, increasing to 500 yuan/ton when the weight reaches 1. In a comprehensive disposal scenario, including recycling, incineration, and illegal dumping, the optimal fee rises progressively with environmental emphasis, ranging from 100 yuan/ton to 500 yuan/ton. These findings suggest that a 300 yuan/ton fee may serve as a stable baseline, supporting a sustainable and cost-effective CW management approach. The framework offers a decision-support tool that accounts for stakeholder priorities and guides sustainable CW management by aligning economic incentives with environmental preservation.