**8. Conclusions**

the socio-economic objectives. The WLC was used to create three final landfill suitability maps using different weights applied to the objectives. The scenario (a) allots a weight of 0.75 to the environmental and 0.25 to the socio-economic objective; for scenario (b) both objectives have the same weights and for scenario (c) weights of 0.25 and 0.75 are used for the environmental and the socio-economic objectives, respectively. It should be mentioned that we select the sustainable development scenario which assigned the equal weight to the environmental and socio-economical factors (0.5 for each factor). The final suitability map for the mentioned scenario is shown in **Figure 4**. Using an equal interval classification method, landfill suitability values of the Ariana region were classified into five groups: high suitability (8–10), suitable (8–6), moderate suitability (6–4) and low suitability (4–2) and very low suitable (2–0). This method divides the range of attribute values into equal-sized sub-ranges. This creates an easy to

82 Fuzzy Logic Based in Optimization Methods and Control Systems and Its Applications

**Figure 4.** Landfill suitability map.

Although it is very difficult and expensive to include geological, hydrological and hydrogeological, social, environmental and economical parameters, studies for selecting the sites for solid waste disposal should be performed for every city in Tunisia. To determine an appropriate landfill site, GIS is a very powerful tool that can provide a rapid assessment of the study area. The selection of suitable landfill sites is very decisive for Tunisia. Ariana region was selected as the study area because it is the fast growing and urban in greater Tunis. Initially, landfill site selection criteria were determined depending on the applicable international literature. Thirteen criteria were evaluated in the present study. The areas that were inappropriate for MSW landfill site were at first determined and covered. Thus, these areas were not considered. Each criterion was evaluated and converted into arithmetical values by AHP. The criteria maps were mapped by GIS using the calculated numerical values. Using the same interval classification method, the study area was classified into four groups of high, moderate, low and very low suitability, which covered 3.24, 7.55, 12.70 and 2.81% of the study area, respectively. The results of the analysis were compared with field studies, and two candidate landfill sites (C1 and C2) were selected from the high suitability regions. These sites are also close to highly populated settlements. Finally, it is recommended that the methodology adopted in this research to be developed through integrating the indigenous data which might lead to better site selection.
