Site suitability evaluation of an old operating landfill using AHP and GIS techniques and integrated hydrogeological and geophysical surveys

Abstract

Because of the outdated methods of common landfill selection, it is imperative to reevaluate the usage suitability. To assess the suitability of the existing waste landfill in Zanjan, Iran, we have used a combination of the analytical hierarchy process (AHP) and GIS techniques, along with fieldwork surveys. Four major criteria and 12 subcriteria were considered, and the AHP was applied to assign the relative importance weights of criteria and subcriteria to each other. Finally, a landfill suitability map was generated and ranked based on the final suitability scores. The results show that the unsuitable areas are around Zanjan, in the middle parts of the plain. By contrast, the most suitable areas are uncultivated areas, located mostly in the west, north, and south. The results also indicate that the present landfill is a highly suitable site. After desk studies, geoelectrical surveys and infiltration measurements were conducted to make the final decision. Double-ring permeability tests confirm the landfill is an acceptable site. The electrical sounding shows that the leachate plume has a width of about ~ 450 m, spreads to a depth of about ~ 55 m, and migrates towards the northeast. Considering the groundwater depth, dry climate, and a low infiltration rate of the landfill soils, it can be concluded that leachate plumes will not contaminate groundwater within this decade. The proposed method can be implemented to reevaluate the suitability of any old operating reservoir such as oil reservoirs, petrol filling stations, heavy industrial tanks, and landfills, containing liquid hazardous materials.

Sanitary landfill site selection using multi-criteria decision analysis and analytical hierarchy process: A case study in Azuay province, Ecuador

“…Here, an SLF site selection is conceived from four perspectives: technical, environmental, social, and economic, plus the constraints. Similar studies have been carried out by Kamdar et al (2019), Karasan et al (2019), Pasalari et al 2019, Saatsaz et al (2018), among others. Then, there is the meso-scale, or second level, which looks at those variables that play a significant role into the SLF site selection, called criteria (factors and constraints).…”

“…According to the Ecuadorian regulation, there were considered seven constraints: a buffer of 500 m from urban areas and populated centres to protect public health from air, soil, and water contamination; a buffer of 13 km from airports because odour and noise of SLFs produce an uncomfortable environment for passengers; in the case of aeroplanes, an SLF could cause unfavourable conditions associated with the presence of birds (Saatsaz et al, 2018); an influence zone of 500 m around archaeological sites to maintain the community's historical memory and identity; a proximity area of 200 m from rivers must be restricted (Figure 6(a)), as well as all protected natural areas (Figure 6(b)); and, finally, landslide-prone areas (Figure 6(c)) and floodingprone areas (Figure 6(d)), as they may cause deaths, damage, economic losses, and environmental disasters. Thus, such hazards must be taken into account for assertive SLF building to reduce negative consequences (Eskandari et al, 2016).…”

Framework, method and case study for the calculation of end of life for HWL and parameter sensitivity analysis

“…As shown in Fig. 6c, the aquifer thickness has an approximately logarithmic relationship with the EOL; thus, increases in aquifer thickness will result in increases in the EOL 45 , with much greater growth occurring when the aquifer thickness increases from 5 to 10 m. These findings indicate that, when the aquifer thickness is less than 10 m, the EOL of the landfill will be significantly reduced. Correlation analysis showed that the thickness of the vadose zone and aquifer has a positive relationship with the EOL, with correlation coefficients of 0.99 and 0.72, respectively, indicating that the vadose zone thickness has a greater impact on EOL than the aquifer thickness.…”

A worldwide meta-analysis review of restriction criteria for landfill siting using geographic information systems

“…The depth to groundwater was used in approximately 14% articles reviewed, and the values vary from the minimum 5 m used by Babalola and Busu (2011) and Eskandari et al (2012); this latter article also added that the previous 10 years of groundwater depth variation should be taken into consideration. The maximum groundwater depth value found was 39 m, used by Saatsaz et al (2018), who conducted a local hydrogeological and geophysical survey to determine that the zone is not safe from leachate contamination until this depth. In the statistical analysis, the IQR from depth to groundwater is between 7.5 and 25 m, the median is 15 m, and the mean is approximately 18 m (Table 4 and Figure 7g).…”