جستجوی مقالات مرتبط با کلیدواژه "پسماند جامد شهری" در نشریات گروه "محیط زیست"

The most important objective of this paper is to provide an appropriate model for selecting best waste-to-energy technology for both private and public sector managers and investors. Urban waste management combined with energy recovery can be the most suitable solution not only for preserving environment but also for producing and supplying energy to urban and rural communities. Determining the most appropriate waste-to-energy technology is a challenging and complex process, requiring consideration of a wide range of diverse criteria. For this purpose, this study tries to apply two of the most widely used Multi-Criteria Decision Making (MCDM) methods, TOPSIS and VIKOR. Anaerobic digestion (AD), incineration, and pyrolysis were chosen as the main options for waste-to-energy conversion technologies. These options were evaluated based on three main criteria: environmental, technical, and economic, each of which included various sub-criteria. The results of pairwise comparisons indicate that among main criteria, environmental criterion holds the highest score and importance, followed by the economic and technical criteria, respectively. To ensure reliability, the options were ranked using three different MCDM models methods Analytic Hierarchy Process (AHP), VIKOR, and TOPSIS. The overall results of the decision-making models show that incineration is the best waste-to-energy technology, followed by anaerobic digestion and pyrolysis in respective order.

Due to the increasing use of biomass technologies, especially methane gas produced from the decomposition of organic matter in municipal solid waste and its use as a source of energy production, and the importance of methods used in estimating methane gas and Energy production, a study based on the use of mathematical models to estimate the methane gas produced at the Mashhad landfill.

This research was conducted in 1398 in Mashhad. The method used in this study is based on the use of IPCC mathematical models developed by the US Environmental Protection Agency (EPA).

According to mass balance and stoichiometric calculations performed for two categories of fast biodegradable and slow biodegradable materials, about 53.89% of the total landfill gases are methane and 46.11% are carbon dioxide. According to the calculations, the potential for methane production capacity is 115.33 cubic meters of methane per megagram of waste and the methane production rate is 0.021 per year. The data were analyzed in Landgem software.

According to the results obtained in 1414, the maximum volumetric flow of methane produced is 2.6×107 cubic meters per year. Also, the high and low thermal values of landfill gas are 21.484 and 19.361 megajoules per cubic meter, respectively. In case of direct use of landfill gas in power generators, in 1414, the highest net output power with high and low thermal value of landfill gas can be obtained 11503.633 kw and 10366.83 kw, respectively.

The appropriate site selection is an important issue for waste management activities in developing countries. An inappropriate landfill site may cause negative environmental, economic, and ecological impacts. Sanandaj city, western Iran, with a population of 370, 000 people faces daily production of 330 tons of solid wastes. Current landfill site of the city has caused environmental problems, while losing its capacity. This study attempted to determine appropriate landfill sites for municipal solid wastes in Sanandaj city through combination of Geographic Information System (GIS) and Multi-Criteria Decision Making (MCDM) techniques. For this purpose, nine information layers were weighted according to Analytic Hierarchy Process (AHP) and Inversion Hierarchical Weight Process (IHWP) methods. The final suitability maps for a landfill construction in both methods obtained by using overlay function and seven exclusionary criteria, which were used to prepare the restriction map. The result of this study showed that IHWP method increased the accuracy of the final decision for identifying best quality landfill sites and provided better results in comparison with AHP. Finally, an area with the extent of 87 ha, located approximately 5 km north-west of the Sanandaj, was identified as priority number one to establish a landfill site.

The waste generation is the product of different human activities that have been transformed because of the change of life style and multilateral development. By progression in science and technology, waste management has been reviewed scientifically. Within the eight branches of functional elements of municipal solid waste management system, generation, collection and transportation have especial importance. The significance of waste generation is due to being the first loop in the chain of recycling and reducing production is the base of comprehensive solid waste management pyramid .Otherwise the greatest part of costs for managing solid waste systems relates to collection and transportation of wastes.
In this paper we described municipal solid waste management system and dynamic modeling methodology. After that we reviewed the literature research about dynamic modeling of municipal solid waste management systems. In the next step, we illustrated a dynamic model for generation, collection and transportation of wastes in the city of Tehran. Then we analyzed the findings from the base run of model and examined that with validation tests to gain accredited model.
Result& After achieving a valid model the improved scenario have been built based on 3R techniques and policy and sensitivity analysis. In Tehran city, emphasis on reducing production and decreasing of per capita waste generation, awaken citizens and officials on necessity of separation wet and dry wastes in era and Effort to improving the performance of Dry waste separation plan are the best options to manage generation ,collection and transportation wastes subsystems .

CIE color standard system has been extensively used to determine various physic-chemical characteristics of porous media such as soil. Objective of this study is to evaluate the relationship of C/N ratio and organic matter percentage with parameters of CIELAB color standard system during composting production process.

In this study, changes on parameters of CIELAB color standard alongside with organic matter percentages and values of C/N ratio were measured for 90 days during urban solid wastes materials’ composting process in Arad-Kouh factory in Tehran.

The results showed that there are significant relationships of L* with organic matter (r=0.942, α=0.01) and ratio of C/N (r=0.915, α=0.01) from one hand and parameter of a*/b* with organic matter (r=-0.876, α=0.01) and ratio of C/N (r=-0.893, α=0.01) from other hand.

Statistical interpretation of the obtained results approved that instead of common analytical methods for quality evaluation of composted materials; parameters of L* and a*/b* are easy, inexpensive and quick to estimate ratio of C/N and organic matter percentage of composted urban solid wastes materials reliably.