A System Dynamics–Optimization Framework for Sustainable Municipal Solid Waste Management: Integrating Behavioral Feedbacks, Technology Selection, and Circular Economy Pathway

Rapid urbanization and rising waste generation have intensified the environmental and economic challenges of municipal solid waste (MSW) management, particularly in systems that rely on landfills. This study develops a hybrid system dynamic–optimization framework to identify sustainable long-term MSW management pathways by integrating technological, economic, environmental, and behavioral feedback mechanisms. The framework couples a system dynamics model with a β-Hill Climbing optimization algorithm to evaluate waste treatment strategies, including recycling, composting, anaerobic digestion, incineration, pyrolysis, gasification, and landfilling, under alternative policy scenarios for 2027–2050. The proposed framework is applied to Alborz Province, Iran, to optimize technology portfolios while considering citizen participation, financial constraints, and environmental objectives. Results show that integrated policies substantially outperform single-technology approaches, reducing cumulative landfilled waste by 91–93% compared with the baseline scenario. Anaerobic digestion is the most effective option for organic waste management, while the optimal dry-waste treatment pathway depends on participation levels and economic conditions. Under limited participation, pyrolysis is preferred due to lower investment requirements, whereas enhanced participation supports a combination of incineration, pyrolysis, and gasification for improved resource recovery. The optimized strategies transform the MSW system from a net greenhouse gas emission source into a mitigation-oriented system, achieving cumulative reductions of 24.44–25.96 million tons of CO₂-equivalent. The results demonstrate that sustainable waste transitions require coordinated behavioral policies and technology planning rather than isolated technology selection. The proposed framework provides a decision-support tool for designing circular and low-carbon MSW management systems under dynamic socioeconomic conditions.