Life cycle assessment of the dominant scenarios of waste management system in the north of Iran

Environmental life cycle assessment (LCA) is especially important for developing countries like Iran, where waste management practices are often inadequate and have significant environmental impacts. Landfilling is a common waste management practice in Iran, but it can have detrimental effects on the environment and public health. Conducting an LCA for landfill scenarios and their alternatives can help decision-makers identify the most sustainable waste management practices and minimize the negative environmental impacts. LCA can also provide valuable insights into the environmental and economic trade-offs associated with different waste management scenarios, allowing for informed decision-making. By incorporating LCA into waste management planning, Iran can reduce its environmental footprint, mitigate climate change, and improve the overall sustainability of its waste management practices. Accordingly, this study evaluates the environmental impact of two dominant waste management scenarios in the north of Iran: L (all waste is landfilled) and CL (some organic waste is diverted from landfill and composted, the remaining is landfilled). Initial data was collected from the waste management organizations of three main cities - Rasht, Sari, and Gorgan - which serve as centers of their respective provinces. The functional unit: “treatment of 100 tons of municipal solid waste (MSW)” is selected for the present research, and the system boundary is considered from the MSW collection station to either finishing landfill process or compost production. The ReCiPe2016 Midpoint (H) method is also used for life cycle impact assessment to evaluate environmental characterization. Additionally, normalization is used to identify the best scenario. Based on the results, in both scenarios, climate change is the most significant midpoint impact, accounting for over 90% of total normalized impacts. Additionally, direct emissions account for over 95% of the main hotspots in both scenarios. In the CL scenario, the production of compost has a significant effect on reducing other midpoint impacts. The results indicate that transportation, accounting for more than 70%, especially in the landfilling scenario, has the highest environmental burden in most other midpoint impacts. In the final step, a comparison between the two scenarios indicates that the total normalized impact is 30.54 for the L scenario and 6.05 for the CL scenario. Based on these results, it can be concluded that the CL scenario offers several environmental benefits over the landfilling scenario, including reduced greenhouse gas emissions, minimized transportation requirements, and effective waste reduction through the production of nutrient-rich compost. This makes the CL scenario a more sustainable and environmentally friendly approach to waste management.