Network Analysis of Waste Collection Systems and Guidelines for Finding Landfill Areas a Case Study of Songkhla Municipality, Songkhla Province

Abstract

                The objectives of this research were: 1) to analyze the shortest route for waste collection service in Songkhla Municipality and 2) to determine the suitable areas for constructing landfilling. Geoinformatics technology was applied to consider the route of waste collection from the starting point, the waste collecting points, and the waste dump point for each vehicle in each route and to find suitable areas for new landfilling. According to the selection of spatial factors by using 2 scenarios, the first scene was the factors and criteria for sanitary landfill disposal of Pollution Control Department Regulations under 2 conditions: 1) if pass criteria were 1, if not pass criteria were 0. The second scene was the literature review on various research trends to determine the appropriate factors combined with the Multiple-Criteria Decision Analysis (MCDA). The weighting method and expanding incremental rating of the first scenario were addressed with the Analytic Hierarchy Process (AHP). The results were divided into 3 levels: the most suitable area, the moderately suitable area, and the less suitable area. In addition, the water recourses, moderately suitable area, less suitable area, and the forests were excluded and considered selecting only the size of the area greater than 500 rai. In terms of the shortest route for waste collection, it reduced the distance of waste collection by 13.2 kilometers. In the part of the analysis, the suitable areas based on the first scenario found 8 important factors including 1) geological condition 2) community area 3) natural water source or excavated canal 4) distance from underground wells 5) distance from archaeological/historical sites and sanctuaries 6) watershed quality class 7) airport area and 8) conservation area. The areas that had passed the criteria were 292,214 rai namely Sadao District, Khlong Hoi Khong District, and Ranot District were 87,650 rai, 29,491 rai, and 28,931 rai, respectively. In the second scenario, it was found that there were 5 factors: 1) the aspect of the ancient site, 2) the distance from the main highway, 3) the distance from the natural water source or canal, 4) the distance from the community source and 5) the slope which appeared in Khlong Hoi Khong District and Sadao District. The results of the analysis will be an alternative to support waste management decisions, improve the efficiency of waste collection, and plan guidelines for implementation and determining future landfill sites. Keywords :  Network analysis, waste collection, landfill, the shortest route, Analytic Hierarchy Process