Comparison of the Environmental Impacts of Different Municipal Solid Waste Treatments using Life Cycle Assessment (LCA) (Case Study: Tehran)

Background and Objectives: The continuous increase in solid waste generation worldwide due to population growth and industrialization, calls for management strategies that integrate concerns for environmental sustainability. By quantifying environmental impacts of systems, Life Cycle Assessment (LCA) is a tool which can contribute to answering that call. The aim of this study was to evaluate environmental pollutants resulting from various treatment options including anaerobic digestion, incineration, and landfill of Municipal Solid Waste (MSW) generated daily in Tehran. Materials and Methods: First, the physical properties of the waste and consumption of inputs in the study area were determined from September to October, 2014- 2015. Then the different steps of LCA in relation to each of the subsystems were followed (with SimaPro software). Finally, the results based on the CML Baseline 2000 were presented and analyzed. Results: It was found that when the higher rate of separation and processing in any subsystems increases, the emission of environmental pollutants decreases, so that the global warming potential, acidification, eutrophication, and abiotic depletion as the most important impact categories in the subsystems of anaerobic digestion were obtained as -125935 kg CO2/day, -449 kg SO2/day, -1690 kg PO43-/day and -0.43 kg Sb/day, respectively and in incineration were obtained as -264872 kg CO2/day, -974 kg SO2/day, -3471 kg PO43-/day and -0.76 kg Sb/day, respectively, while in the landfill subsystem, they were estimated to be 74478 kg CO2/day, 362 kg SO2/day, 118 kg PO43-/day, and 0.13 kg Sb/day, respectively. Conclusion: According to the constituent processes of each of the subsystems and the results of the evaluation of exhaust emissions subsystems, it can be concluded that in an integrated system of waste management, the energy-generating systems such as anaerobic digestion and incineration should be as the first priority and the traditional subsystems such as landfill should be as the last priority