Comparing the Scenarios of Current Conditions and the Development Plan for the Waste Management System in Rasht County Using the Life Cycle Approach

Improper waste management threatens the sustainability of the environment. Defining an optimal and sustainable system for waste disposal requires the examination of all processes within the system, their impact on the environment, economic aspects, implementation, and energy consumption in each part. The present study was conducted with the goal of modeling the municipal solid waste management system of Rasht County based on the life cycle assessment approach. In this regard, two existing disposal scenarios and the development plan for the future were compared. The first scenario (existing disposal) includes the sale of recycled waste, biological processing (compost production), and landfilling. The second scenario (development plan) involves the use of an incinerator in addition to previous disposal methods. After collecting data using the IWM-2 model, the environmental impacts of each scenario were assessed. The results show that if the second scenario assumptions are applied, the amount of energy consumption, pollutants, and global warming will decrease relative to the first scenario. Total energy consumption in the first and second scenarios is respectively +3891 and -1683234 Gj. In addition, the global warming potential is reduced due to the reduction of landfills, reduced transportation and fuel consumption, improved equipment, and energy recovery in the second scenario. In general, environmental performance in the second scenario will be improved if appropriate action is taken. Reducing landfill and greenhouse gases, increasing recycling, etc., are the main reasons. Although incineration reduces landfilling in Saravan, it is still the proper design of the landfill, and energy utilization from it provides a favorable life cycle of waste management based on the second scenario. Moreover, the use of waste incineration is justified only if pollution and energy recovery standards are respected. Modifying the components and capacity of each disposal option produces new results. In this context, it is suggested to use alternative models.
Extended Abstract
1-Introduction
Increasing municipal waste generation is one of the drawbacks of modern urban life. Improper waste management threatens the sustainability of the environment and has a significant contribution to many environmental problems such as greenhouse gas emissions, reduction of resources, etc. Defining an optimal and sustainable system for waste disposal requires the examination of all processes within the system, their impact on the environment, economic aspects, implementation, and energy consumption in each part. In this context, life cycle assessment as an environmental management tool can help decision-makers and managers recognize the environmental characteristics of options and optimal selection. Currently, the waste management system in Rasht County generally includes burial and biological processing. According to the sensitive and vulnerable ecosystem of the region, the investigations show that the management methods of waste disposal have not been effective and have not been successful in achieving the goals of optimal waste management. The present study was also conducted with the goal of modeling the waste management system of Rasht County based on the life cycle assessment approach. This study emphasizes the comparison of energy consumption and global warming potential in different waste disposal scenarios.
2-Materials and Methods
This study focused on a comparison of the current state of Rasht's waste management system and its future development conditions. In this regard, two disposal scenarios: the existing (sale recycling waste (0/5 percent), biological processing (8/7 percent), and landfilling (90/8 percent)) and the development plan (sale recycling waste (4/9 percent), biological processing (43/3 percent), landfilling (4/6 percent), and incineration (47/2 percent)) have been compared. It is emphasized that the applied percentages are based on the current situation and the forecasted information for the waste management of Rasht County in the future. Also, the studied border starts from the collection of waste from Rasht City as a transfer point and ends when it reaches the final disposal site. After collecting data using the IWM-2 model, the environmental impacts of each scenario were assessed. The windows in this model include the stages of collection, separation, and recycling of materials, biological processing, thermal processing, landfill, and energy production, respectively. The necessary information and assumptions at this stage were included based on the statistics obtained from the waste management organization as well as the contractual data available in the comprehensive waste management software.
3- Results and Discussion
1156 tons of municipal waste are produced and disposed of in Rasht County daily. According to the physical analysis of waste, most components of it are organic materials with a share of 58.72 percent and a weight equal to 678.8 tons of total waste. The results show that if the second scenario assumptions are applied, the amount of energy consumption, pollutants, and global warming will decrease relative to the first scenario. Total energy consumption in the first and second scenarios is respectively +3891 and -1683234 Gj. The results show that the recycling of one kilogram of recycled materials preserves significant energy compared to the production of the same material from raw sources. In addition, the global warming potential is reduced due to the reduction of landfills, reduced transportation and fuel consumption, improved equipment, and energy recovery in the second scenario. In general, environmental performance in the second scenario will be improved if appropriate action is taken. Reducing landfill and greenhouse gases, increasing recycling, etc., are the main reasons. The most greenhouse gases produced in the first scenario are CH4 and CO2, which are released during the illegal landfilling in Saravan.
4- Conclusion
Conducting a life cycle assessment study by comparing the environmental burdens caused by disposal processes allows decision-makers to identify the weak points and also the most appropriate disposal pattern and plan in line with sustainable development. Although incineration reduces landfilling in Saravan, it is still the proper design of the landfill, and energy utilization from it provides a favorable life cycle of waste management based on the second scenario. Moreover, the use of waste incineration is justified only if pollution and energy recovery standards are respected. Modifying the components and capacity of each disposal option produces new results. In this context, it is suggested to use alternative models. The results of this study were conducted according to the conditions and composition of the waste in the study area and can be different from the results of other studies. Therefore, it is not possible to compare the results and generalize them to different regions, and naturally, the necessary measures will change based on environmental limitations and capabilities.