Identifying Optimum Sites for Safe Dumping of Rural Waste by Combining the AHP and DRASTIC Methods in the GIS Environment (Case Study: Shavur District, Shoosh County)

1. The practice of choosing the proper location for sanitary disposal of waste is a difficult, complicated, long and expensive process. This cannot be done without using a robust and reliable system that has the ability to use and analyze multiple strata of data. GIS is very suitable because of the capacity to deal with a great quantity of data. The system has the ability to simulate and control the parameters of hydrology, hydrogeology, physiography and the environment. The purpose of this research is to find a suitable waste landfill site in Shavur district of Shoosh city using the analysis of the parameters of the drastic model through the GIS and the hierarchical analysis process. In other words, this research attempts to analyze the components that are important in locating landfill in Shavur, Shoosh, through the GIS and AHP techniques, and identifies the most suitable site for solid waste disposal, which has the least harmful environmental and human impacts, and to provide the findings in the form of the map.
2. THEORETICAL FRAMEWORK: The concept of the landfill is a useful method to choose a landfill or waste site. Locating proper sites for municipal or rural waste disposal is a complex and multidisciplinary process that requires environmental, ecological, social, economic, technical or specialized considerations. Lack of land for landfill and population growth are two greatest challenges in urban and rural areas in the world. Hence, the selection of places for landfill is the major problem facing the waste disposal management system. Given the importance of the rural community and the challenges that such community faces in its development process, recognizing the characteristics of rural development planning and addressing all aspects of it are essential. Therefore, it is necessary to pay particular attention to waste management in national programs. Over the past few years, with the help of GIS capabilities, many studies have been conducted to facilitate the process of selecting waste disposal landfills and to decrease the expense of constructing such sites, in order to keep up the process of environmental protection and to meet the objectives of sustainable regional development as well as logically managing development plans and projects. The hierarchical analysis process is flexible, strong, and simple. It is used in situations where conflicting decision-making criteria make choosing between options difficult to apply. This multi-attribute assessment approach was first proposed in 1980 by Thomas L. Saaty, and has been numerously used in regional planning. In addition, the dramatic model is based on seven hydrological parameters that include ground water static depth, net nutrient level, aquifer material, aquifer environment, soil or soil layer material, topography slope, the effect of the unsaturated environment and hydraulic conductivity of the aquifer.
3. In terms of purposing, the present study is applied, and in terms of its nature and method, it is a descriptive and analytical research. Data collection has been done via documents and surveys. To achieve the objectives of the first research, the site's talent recognition camps for waste sanitary landfill, including five issues related to the human, hydrological, communication, environmental and topographic indicators, were identified with two variables. A total of 10 were identified. These criteria were estimated when a questionnaire was completed by 30 experts, using the AHP hierarchical process analysis, and it was valued in the Excel and Expert Choice environment, and the compatibility of each of the criteria and sub-criteria was estimated. Secondly, in order to prepare a vulnerability map for groundwater due to leakage of leachate, the seven hydrological parameters of the Drastic method were used, which include the following: groundwater depth (D), net nutrient (R), aquifer type or saturated environment (A), Soil layer (S), topographic gradient (T), influence of the environment of Vados, or unsaturated medium (I) and hydraulic conductivity (C). To show the mentioned spatial parameters, the layer of Shavur section of Shoosh was combined with the weights of the criteria in the ArcGIS 10.3 environment and the UTM coordinate system in Zone 39. Interpolation, Distance, and Surface functions in the Arc Toolbox menu were used to adjust the evaluation layers so that the most suitable and most demanding sites for rural waste disposal can be extracted from the output Layers. It should also be noted that for the production of the map of each of the parameters of the drastic method, the data from the study plan of hydro climate balance excavation of the Ahoodasht district of Shoosh city (Company in charge: Water and Power Organization of Khuzestan province) were used.
4. The results of the research show that from the total area of the site, about 39.38% of it is in a very inappropriate level. In other words, these areas are not suitable for waste landfill operations. After that, perfectly appropriate levels with 20.1%, appropriate levels of about 21% and relatively appropriate with 20.4% of the area are the next respectively. What is deducted from the final map is that from the total completely appropriate areas, three sites with titles; Landfill 1 to 3 have the best places to implement the project and have a better priority than other areas.
5. The proposed sites have been identified based on many environmental characteristics such as distance from surface water and underground water, distance from biological complexes such as towns and villages, distance from agricultural areas, distance from protected areas and proximity to major roads for ease of transfer and by taking into account the landfill location criteria. The location of each of the sites is as follows: Landfill No. 1, one kilometer away from Shavur, and two kilometers from the village of Khois, Landfill No. 2, seven kilometers from Alvan and two kilometers from the village of San Karim, and Landfill No 3. It is located nine kilometers from the city of Alvan and one km from the villages of Akiush in the south, and Khalaf Aziz in the north. In the end, it should be noted that any method, while having advantages, has limitations which can be determined in subsequent research by comparing the results of this method with other methods. The more numerous and more precise criteria and indicators are, the better the results will be. As a matter of fact, this requires further research in the future.