USE OF GEOGRAPHIC information SYSTEM IN LANDFILL SITES SELECTION
USE OF GEOGRAPHIC INFORMATION SYSTEM IN LANDFILL SITES SELECTION
Using Remote Sensing and Geographic Information Systems (GIS), this study identifies viable areas for solid waste dumping in the region of Jos-North. Remote sensing was utilised to create a landuse map of the study region, and GIS was used to integrate several layers of information, all with the same spatial reference, to create a solid waste dump suitability map.
The work required a variety of different criteria, each with a different amount of priority. To account for the importance of each criterion, the Multicriteria Decision Analysis (MCDA),
specifically the Analytic Hierarchy Process (AHP), was used. For this aim, nine (9) input map layers were created and used as constraint criteria for determining appropriateness, including settlements, roads, wetlands, slope, geology, soil, landuse, floodplains, and surface water.
For the final suitability map, the weighted overlay tool in ArcGIS 9.3 was utilised, and the results were acceptable. 20.8km2 of the total research area of 291km2 was deemed to be suitable for sustainable landfill siting. The geology, hydrogeology, and land use map layers are based on available data.
The information given by these maps was not entirely sufficient because they were not especially created for landfill site selection purposes. It is recognised that maps depicting the distribution, thickness, and features of unconsolidated surface deposits are more useful than general purpose lithological maps.
Thus, specific purpose engineering geology and hydrogeological maps are necessary for landfill siting investigations. The slope layer must be modified to exclude areas around ridges and hill tops.
1.1 BACKGROUND OF THE STUDY
Yesilnacar and Cetin (2005) argue that solid waste management is critical to public health and environmental conservation. Its primary goal is to offer sanitary, efficient, and cost-effective collection,
transportation, treatment, and/or disposal of solid waste without harming the atmosphere, soil, or water resources, and the management plan should address the aesthetic issue (UNDP, 1997).
The global increase in municipal solid waste creation has been attributed to urbanisation, industrialization, and population expansion, as well as increased living standards (Rao, Brinda, & Harikrihna, 2007).
The United Kingdom is estimated to generate 35 million tonnes of municipal solid waste per year (Koshy, Emma, Sarah, Tim, & Kelly, 2007), and the United States of America generates more than 140 million tonnes per year, while Japan and Germany generated 50.2 million and 43.5 million tonnes, respectively, in 1993 (Sakai et al., 1996).
Africa's predicament is similar to that of the rest of the world. Nigeria creates around 20 kg of solid trash per capita each year, with a population growth rate of about 2.8% per year and an urban growth rate of about 5.5% per year (Imam, Mohammed, Wilson, & Cheeseman, 2008).
Furthermore, the average Nigerian generates roughly 0.49kg of solid garbage each day, whereas commercial centres and families produce nearly 90% of total waste found in urban areas (Solomon, 2009).
Insufficient solid waste disposal is the second most severe problem that city people confront (after unemployment), according to a United Nations Development Programme survey of 151 cities from across the world (UNDP, 1997). To deal with the challenge, a fully sustainable waste management practise is needed.
Solid waste is properly managed in industrialised countries through an effective management process of trash reduction, reuse, recycling, and proper disposal. However, in developing nations, municipal solid waste management systems are either inefficient or primitive, and as a result, solid waste generated has become a concern to the environment (Solomon, 2009).
For example, in Jos North, waste is commonly thrown within culverts and rivers, and when the rainy season begins, flooding becomes a typical occurrence in the city of Jos (Wuyep, 2011). In terms of dumping waste in the River Dilimi,
a major drainage of the Jos-plateau, Abdullahi (2008) finds heavy metals in vegetable crops planted along the river that exceed the WHO limit of exposure and attributes this to waste dumped into the river as well as fertiliser run-off from farm lands. As a result, appropriate garbage disposal is critical for achieving sustainable waste management.
Rao et al. (2007) state that in order to develop a sustainable solid waste management system, policies and practises such as waste recycling, reuse, waste reduction, thermal treatment, landfilling, and so on must be implemented.
Landfilling is the most often used technique in several countries (Yesilnacar & Cetin, 2005). Landfill is a technique for disposing of solid waste onto or into land while considering social, economic, and environmental factors (Rao et al., 2007).
Sanitary landfilling is the technique of disposing of refuse on land that causes no nuisance or danger to public health or safety by using engineering principles to confine the refuse within the smallest practical volume and cover it with a layer of earth at more frequent intervals as needed (UN-HABITAT, 2010).
Open or uncontrolled dumping is widely used as a waste disposal method in Nigeria, but the advantage of sanitary landfill over open dumping methods cannot be overstated because it is pollution-free, thereby eliminating any health or environmental risk that may result from solid waste disposal (UN-HABITAT, 2010).
However, municipal landfill siting is becoming increasingly challenging due to the risk of unfavourable environmental pollution and degradation, as well as health dangers, if the site is too close to a residential area, a river, a water channel, or another delicate ecosystem (UN-HABITAT, 2010).
According to Sakai et al. (1996), a properly designed and wellmanaged landfill can be hygienic and relatively inexpensive, whereas a poorly designed or poorly managed landfill can cause a variety of environmental problems such as ground water contamination,
wind-blown litter, vermin attraction, and uncontrolled emission of landfill gases such as methane. Communities have refused to adopt landfills as a result of such issues (Yesilnacar & Centin, 2005).
To safeguard the ecosystem from disruption and to guarantee a healthy environment for human life, landfills must be carefully located in environmentally acceptable sites (Sakai et al., 1996). The selection of landfill sites entails a thorough examination process in order to locate the best possible disposal location.
This location must comply with fundamental government requirements while also considering ways to minimise significant issues such as health, economic, environmental, and social costs (Siddiqui et al., 1996).
Indeed, different researchers have utilised diverse criteria for site selection, owing to the fact that different criteria apply to different regions (Stinnette, 1996; Sadek & Fadel, 2006).
Many considerations must obviously be considered in landfill location decisions, and Geographic Information System (GIS) and Remote Sensing are suitable for this type of early studies due to their capacity to manage enormous amounts of spatial data from a number of sources.
GIS is useful for storing, retrieving, and analysing data, as well as displaying data based on user-defined parameters (Siddiqui et al., 1996). According to Kao and Lin (1996), GIS can process a significant amount of geographic data, potentially saving time that would otherwise be spent manually picking an ideal site.
Multicriteria Decision Analysis (MCDA) can be used to address the challenges that decision-makers have when dealing with vast amounts of complicated information.
The strategy divides choice issues into smaller, more intelligible sections, analyses each portion separately, and then integrates the parts logically (Malczewski, 1997).
Because GIS enables quick data manipulation and presentation, and MCDA provides consistent ranking of potential landfill regions based on a range of criteria, the integration of GIS and MCDA provides a reliable platform for solving the landfill site selection problem.
As a result, there is a need for this study to use GIS in the identification of suitable landfill sites for sustainable waste management in Plateau State's Jos North Local Government Area (lga).