Comparative life cycle environmental impacts of two scenarios for managing an organic fraction of municipal solid waste in Rasht-Iran

Population growth and increasing rapidly expanding urbanization in developing countries have led to an increase in municipal solid waste. Accordingly, the municipal solid waste management is a challenging and revolute issue which requires more informed decision making by authorities and experts from a variety of perspectives. Various methods have been suggested for the treatment of municipal solid waste to solve the problems and challenges. However, environmental sustainability should be considered by decision-makers in different ways. The life cycle assessment as a tool can help authorities and experts in the selection of stability methods of municipal solid waste management. Therefore, the objective of this study is to evaluate and compare two scenarios, namely, composting and anaerobic digestion, for managing the organic fraction of municipal solid waste of Rasht city, Iran from an environmental sustainability perspective. Life cycle assessment was used to evaluate the environmental impact of composting and anaerobic digestion of organic fraction of municipal solid waste. In this study, the functional unit is defined as 100 t municipal solid waste and the system boundaries include all proceedings for municipal solid waste transportation from the city to the end of the production process in each scenario. The results showed that the treatment of organic wastes by the anaerobic digestion scenario compared with the composting scenario leads to a reduction of 66.67% in damage to human health, 47.84% in damage to ecosystem quality, and 89.64% in the climate change. Also, the result represents that the treatment of organic wastes by the anaerobic digestion scenario leads to a redaction 21 times in damage to resources compared with when organic wastes are treated by composting scenario. More specifically, the presented results in this study showed anaerobic digestion scenario owing to the treatment of organic wastes and convert them into value-added material/energy has favorable environmental impacts. (C) 2020 Published by Elsevier Ltd.