SUMMARY
The increasing generation of MSW is one of the greatest challenges faced by developing nations across different continents. In order to mitigate the impact of solid waste disposal on the environment and public health, a fast decision-making process regarding the identification of a suitable site for the final disposal of the MSW is required. The task of selecting the most suitable site for solid waste disposal remains the major focus and motivation for this study. The study aimed to select suitable sites for landfill application in Warri using the best methodology and also by taking into account the scientific and environmental, economic social criterions which are followed in advanced countries.
In this study, eleven (11) criterions were used in an over laying analysis of potential areas with GIS to identify a suitable landfill site inWarri. A combination of GIS, AHP and Fuzzy logic models were used; layers such as; flood extent buffer distance, river buffer distance, streams buffer distance, swampy area buffer distance, groundwater elevation, road buffer distance, slope, Built-up areas buffered distance, airport buffered distance, palaces buffered distance, point of interest(POIs)buffered distance were considered. The criteria weightings were derived from the AHP-GIS method by constructing a matrix of pairwise comparisons between criteria. The outcome of the study revealed three potential sites identified by both AHP-GIS method as suitable for landfill application. These three potential sites are located around SPDC scrap yard and Otokutu area. Ground trothing verified and validated the geographical location of the three potential sites for landfill. Site 2 (Otokutu Community) and site3 (Otokutu Community) are not acceptable while site 1(SPDC Scrap Yard) is acceptable because of the result of ground truthing. The fuzzy logic modelling which has the same characteristics with site1 (SPDC Scrap Yard), gave river buffer distance of 2.5km, ground water elevation of 15m, road buffer distance of 2.5km, land slope of 60 and built-up area buffer distance of 20.5km as the most suitable condition for landfill site selection.
The common are as identified in both methods showed the suitable lands for waste disposal with an appropriate criteria buffer distance. Therefore, the result showed that the integration of GIS, AHP and Fuzzy models using multi-scientific with a combination of environmental, economic and social criteria could be used to develop an effective and efficient methodology for selecting suitable landfill sites. It can be concluded that the methodology applied in this present study is in-line with current practice and possess the potential for locating suitable landfill sites in Warri and Nigeria at large. It also can be concluded that the objective set out for this research work has been achieved.
