Introduction
Background to the study
Waste was an early problem of mankind, and a growing one that is of major concern to every nation of the world (Allende 2009). In early pre-industrial times, waste generation was not an issue as populations were smaller. Waste was disposed of in the ground where it would turn to compost to improve soil fertility. Waste management became a growing problem during the transition from nomadic hunting and gathering to farming. Before the industrial revolution, waste reuse and recycling were the major ways of waste management (Anon 2009). However, as populations increased, especially in major cities and urban centres, space for disposing waste became limited and people needed to look for new and better ways for disposing waste. In 400 BC, the first municipal dumpsite was created in ancient Athens in Greece (Anon 1998).
Municipal solid waste management (MSWM) is an ‘important entry point for integrated urban management support (Schubeler 1996)'. It refers to the collection, transfer, treatment, recycling and disposal of solid waste in urban centres (Schubeler 1996). More specifically, it refers to that part of the waste stream that is ‘collected by, or on behalf of, local authorities (Waste Strategy, 2000)'. The primary objective of waste management is to give adequate protection to the general public and environment from harmful effects of waste (Anon 2010).
Municipal solid waste management is a problem that is experienced by all counties in the world. It is an issue mostly witnessed in urban areas as a result of high surge in population growth rate and increase in per capita income thus posing a danger to environmental quality and human health (Javaheri 2006). Because of its nature, it has remained one of the major environmental problems man continues to face.
An investigation into waste management is now becoming increasingly critical in developing countries (Kyessi and Mwakalinga, 2009). Issam et al. (2007) report that waste management that has generally been understudied in developing countries is now receiving increasing attention in the literature. Municipal Solid Waste Management (MSWM) problems have become more pronounced in recent years, as a result of inadequate collection and disposal of wastes. In most cities, wastes are not properly collected and where proper collection is ensured, only a small fraction receives proper disposals (Ayininuola and Muibi 2008).
Solid waste management has become a serious problem in Nigerian cities (Akinola and Salami 2001). The mountainous heaps of solid waste that deface Nigerian cities, and the continuous discharge of industrial contaminants into streams and rivers without treatment motivated the Federal government of Nigeria to promulgate decree 58 for the establishment of a Federal Environmental Protection Agency (FEPA) on 30th December 1988. Despite the formulation of FEPA and national environmental policy, the environment has not been adequately protected with respect to solid waste generation. Waste collection is irregular and restricted to certain areas in the cities while improperly sited open dumps deface several other areas thereby endangering public health by encouraging the spread of odour and disease, uncontrolled recycling of contaminated goods and pollution of water resources. Solid waste generated by an average Nigerian per day is estimated to be around 0.49kg while commercial centres and households contribute almost 90% of the total wastes found in urban centres (Solomon 2009).
Municipal governments at local levels also formulated policies on solid waste management. While some efforts are made to address this issue by organising monthly environmental sanitation exercise, adequate information about appropriate waste collection centres are not commonly available (Lasisi 2009). Sometimes the main objective seems to be to get rid of solid waste in strategic places, though this has not been effectively done as there are many illegal dumpsites. It is clear that there is no adequate plan for proper waste collection and disposal (Lasisi 2009).
The disposal of waste has proved to be a major public health issue and a vital factor affecting the quality of the environment. This, especially in Nigerian cities has become one of the most intractable environmental problems today. Municipal Solid Waste disposal is now a particularly worrying issue that can be likened to a ‘monster' staring the authorities in the face (Kironde 1999).
There are various techniques that are currently being used for solid waste management. These include thermal treatment, biological treatment, landfilling and recycling (Kontos et al. 2005). Out of these, landfilling is the most common method used in many countries (Yesilnacar and Cetin 2005). However, in today's society, finding a site to locate undesirable facilities is becoming a significant problem. (Erkut and Moran 1991). Particularly, landfill siting is a big issue due to the prevalent ‘not in my backyard (NIMBY)' and ‘not in anyone's backyard (NIABY)' concerns from the general public (Kao and Lin 1996). Siting of landfill is now very essential because of the imperative nature of landfills due to population expansion and the corresponding volume of garbage (Or and Akgul 1994).
Statement of problem
In many Nigerian cities, there has been a phenomenal increase in the volume and range of wastes generated daily within the past few years (Ogwueleka 2009). This is due largely to the increasing rates of population growth, urbanisation, industrialisation and general economic activities. In these cities, the habit of dumping and disposing waste indiscriminately has become the order of the day and a common practice among dwellers (Sule 1982, Adedibu 1986, Solomon 2009).
Ibadan North is the largest local government in Ibadan (Ayininuola and Muibi 2008). One of the main problems facing the region is open and indiscriminate dumping of refuse (Omoleke, 2004). Piles of decaying garbage are found in strategic locations in the heart of the city. Wastes in such places are obviously a source of air and water pollution, land contamination and environmental degradation. Ayininuola and Muibi (2008) report that one of the factors responsible for poor environmental conditions threatening public health and quality of life of urban dwellers is poor waste management. The situation of solid waste management in this area has now called for a quick action as it would seem that many goals of the Millennium Development Goals (MDGs) might not be achieved by 2015 since waste disposal affects some issues that the MDGs seek to address.
Justification of the study
The environment in which man lives today is heading towards risk as a result of improper waste disposal. ‘Domestic, industrial and other wastes, whether they are of low or medium level are causing environmental pollution and have become perennial problems for mankind' (Ramasamy et al. 2003). Failure to properly handle this situation in a timely manner can lead to a more catastrophic event. With the current level of urbanisation coupled with an absence of places to dispose wastes properly, Ibadan North faces a great environmental problem. This area is not the only area being faced with the problem of improper waste disposal but as there are a lot of changes in daily activities and operations throughout the various parts of the area, particularly in demographic expansion, it has become necessary to look into the issue of waste disposal.
Since there is no adequate provision for proper waste management and disposal system, it is therefore imperative that a landfill facility for proper disposal be developed using GIS. This is because landfilling is now accepted as the most widely used method for disposing solid waste as it is the most economical and environmentally acceptable method in all countries of the world (Tchobanoglous et al. 1993, Sumiani et al. 2009).
Aim and objectives of the study
The primary aim of the study is to identify a suitable site for the construction of a solid waste landfill. The objectives are to:
It is targeted that the results achieved by this study will help policy makers in Ibadan North Local Government Area find a suitable site for collecting and disposing wastes generated in the area and this will in turn assist in solving the problem of indiscriminate dumping as a result of absence of disposal sites which Nigeria as a country is being faced with (Ogwueleka 2009). As there is no study currently that has explored how GIS and MCE can be applied in site selection for waste disposal. This work will spark up an interesting study about the contribution of MCE to GIS in the area of landfill siting Nigerian cities where waste disposal is currently an issue.
The study area
Ibadan North Local Government Area is one of the five local governments that make up the Ibadan metropolis. This area covers wards from Beere roundabout through Oke-Are to Mokola in the South-West and Samonda to New Bodija in the South-East. The local government falls between latitude 7023'00" and 70 27'30" North and longitudes 3052'45" and 3056'00"East (Figure 1). It covers an area of 145.58km, which is approximately 46.6% of the total land area of the city. This makes it the largest in Ibadan (Faniran 1990). It is also the most populated local government area with an estimate population of 202,270 inhabitants (NPC 2006).
Ibadan is the capital of Oyo State and Nigeria's largest city and the largest city in tropical Africa. As the crow flies, it is 128 km northeast of Lagos and 345 km southwest of Abuja, the federal capital. Since its founding the city has had rapid growth, both in area and in population. According to 2006 population census in Nigeria, Ibadan North was estimated to have 306,795 inhabitants. The local government is characterised by large and small industries (manufacturing and agro allied industries); households; and commercial, educational religious and medical centres, as well as other various types of institutions.
