Impact of solid waste classification on urban ecology and economy in Beijing: A quantitative research

The challenge of Municipal Solid Waste (MSW) management has become a critical barrier to the harmonious development of society. China has implemented MSW classification as a pivotal strategy for fostering ecological civilization. Despite extensive research on waste management, there is a lack of comprehensive evaluations that integrate both socio-economic and environmental impacts of MSW, particularly in the context of urban ecological systems. In response, this paper developed an integrated system dynamics (SD) model to evaluate the impacts of MSW classification on urban ecology and economy in Beijing, China. This model comprises three subsystems: waste generation, socio-economic benefit, and environment-resource benefit subsystem. It incorporates feedback loops, sensitivity tests, and extreme scenario testing, all of which have validated the robustness and consistency of the model. Scenario analysis was conducted to examine benefits and loss of MSW classification under different conditions. Using the MSW classification in Beijing from 2010 to 2019 as a case, the model assesses the socio-economic, environmental, and resource effects of waste classification. The assessment of results indicate a correlation between increasing separation rates of MSW and socio-economic gains. Specifically, as the separation rate rises, the socio-economic benefits shift from negative to positive. At optimal MSW separation rates, these benefits could represent up to 0.78% of Beijing's GDP. Environmentally, the model suggests that greenhouse gas emission reductions (in CO2 equivalent) over the 2010–2019 period could have varied from 2.4–3.62 million tons annually. Additionally, our findings reveal that for every 1% increase in MSW separation rate, the yearly potential land savings might range from 1,069.92 m² to 1,276.98 m². These insights from the SD model underscore the importance of waste classification. They serve as a valuable resource for policymakers, and motivate resident participation in waste classification, highlighting the significant role of waste classification in sustainable development.