Landll siting is a complex and challenging operation. It is one of the fundamental problems in waste management, where it is necessary to consider different conditions when it comes to selecting an appropriate site for landll in each area. The factors or criteria we used in this article are environmental, economic, and social criteria. In this research, the Geographic Information System (GIS) and the Analytical Hierarchy Process (AHP) were utilized to select the most suitable sites for landll in Paveh, which the current landfill in this county does not follow environmental laws. In the process of zoning sites for landll in Paveh, twelve various criteria were mapped and join for cover analyses within GIS application to construct the last suitability index map for the site. The weightings of criteria were done with the help of AHP, and the weightings of the criteria were identified based on various factors. For this purpose, we used experts opinions, governmental regulations, and previous literature. Paveh is located in Kermanshah in the western part of Iran with 736 km^2area. The results show that almost 93% of the study areas is improper for landfill sitting.

The AHP technique was expanded by Saaty (1980) and called Analytic Hierarchy Process. It is a usual way of Multi-Criteria Decision Making (MCDM) since it is based on theoretical authority. It has a great ability to solve complex problems throughout the decision-making process in any domain .This method, which reflects natural behavior and human thinking, authorize the decision maker to present the interaction between different criteria in complex and unstructured situations. The AHP method is employed to recognize the consistency of weightings for each criterion, which it works by constructing a pair-wise comparisons matrix. The aim of this chapter is to examine this method in detail in a tangible example for the field of the environment (landfilling). For obtaining this aim, an important criterion that can influence the environment was considered by using geometric integration in Expert Choice with merging the AHP technique and GIS software.