1.1 BACKGROUND TO THE STUDY.
The observed trend of waste accumulation is a continually growing issue of concern not only at local or regional levels but also at the larger global level (Murali, Lakshmana and Nooka, 2014). Management of solid waste is one of the challenges facing urban areas in the world. This is because an aggregation of human settlements has the potential to produce a large amount of solid waste (Oyinloye, 2013). Solid waste therefore refers to the organic and inorganic used-up materials that encompass both a heterogeneous mass of wastes (domestic) as well as a more homogeneous accumulation of agricultural, industrial and mineral wastes (Karsauliya, 2013). Solid waste management on the other hand, refers to “the control of generation, storage, collection, transfer and transport, as well as processing and final disposal” of waste in a fashion that is in accordance to societal and economic needs while at the same time compliant to environmental standards and principles (Rhea, 2003). The main problem of urban waste management however, is worth noting not only due to the large quantities of waste produced and the spatial spread, but also the problems encountered in setting up of the systems for collection, transportation and disposal of the wastes (Murali, Lakshmana and Nooka, 2014). In this regard, solid waste management is a serious problem for cities throughout the world. Municipal solid waste management is one among the fundamental and essential services provided by municipal authorities in any country to keep urban centers clean. The collection, transportation, treatment and disposal of solid wastes, particularly wastes generated in medium and large urban centres, have become a relatively difficult problem to solve (Maity, 2014). In the developing world, indiscriminate waste disposal has been one of the causes of environmental deterioration and they affect environmental parameters such as air, land and water quality. Indiscriminate waste disposal leads to the destruction of the aesthetic beauty of the environment, causes flooding and environmental air pollution (Iro, Okorondu, Mbano and Duru, 2012).
Nigerian cities and other cities in the world are experiencing common problems in managing their Municipal Solid Waste (MSW) as Solid Waste (SW) generation is increasing proportionately with the ever growing urban population. Consequently, thousands of lives are lost every year to environment related diseases such as cholera, diarrhea, malaria fever, typhoid fever, river blindness etc as majority of people in the developing countries live in filthy, cockroaches, rats and mosquitoes infected environment (Idowu, Adagunodo, Esimai and Olapade, 2012). In Sub-Sahara Africa (SSA), the state of Solid Waste Management is fast assuming the scale of a major social and environmental challenge as waste generation, both domestic and industrial, continues to increase world-wide in tandem with growth in population (Ezeah, 2010).
Waste management has been adjudged ineffective in many urban and rural areas of Africa as stated in Federal Environmental Protection Agency for the United Nations Conference on Environment and Development (World Health Organization, 1997). This is consistent with the statement made in the National Assessment Report of World Summit on Sustainable Development in which Nigerian cities were declared to be among the dirtiest in the whole world (Okoye, Odumegwu and Omuku, 2012). Over the years, the spatial organization and existing infrastructure of cities in developing countries pose challenges for sustainable solid waste management programs. Much of the problems arise because the urban spatial structure is characterized by high density, unplanned settlements, limited road access, and ever increasing rural-urban migration (Cohen, 2006).
Urban centers are major attractions for the location of private and public facilities which require strategic spatial decision support to enhance practicable maximum service. The science of locating a facility otherwise referred to as a facility location problem, has attracted much attention over the last five decades (Farahani and Hekmatfar, 2009). According to Miller and Shaw (2001) there are three general types of facility location problems:
- a) Median problems (minisum): the location of facilities to minimize the total or average travel
cost between demand locations and facilities.
- b) Center problems (minimax problems): the location of facilities so as to minimize the
maximum travel that any customer will travel to a facility and,
- c) Requirement problems: the location of facilities according to some pre specified performance
The median problem is specifically relevant in solving waste bin location problems which is usually to minimize distance between waste generation points and service points. The aforementioned supports location modeling in GIS environment as an efficient way to improve service coverage and efficiency in municipal solid waste management. GIS is one of the most sophisticated modern technologies for capturing, storing, manipulating, analyzing and displaying spatial data through the organization of these data into thematic layers in the form of digital maps (Sutton, Dassau, and Sutton, 2009). Therefore, the combined use of GIS with advanced related technologies (e.g., Global Positioning System) will assist in the recording of spatial data and the direct use of these data for analysis and cartographic representation. Hence, with the paramount factors (minimum walking distance, maximum service coverage, as well as consideration of physical and socio-cultural context of the service area) that determine the location of a waste bin being integrated in GIS, it is believed that more efficient results would be produced by applying GIS to waste management in Lokoja.
1.2 STATEMENT OF THE RESEARCH PROBLEM
Lokoja was once the colonial administrative capital of Nigeria (Adah.2014), it became the headquarters of Kogi Local Government Area as far back as 1976 and was later made Kogi State capital in 1991. Since then, there have been massive changes in all activities of Lokoja including its size, structure, population and other socio-economic development (Olawepo, 2009). These changes have not only reflected rapid growth in MSW generation but constitute a problem to effective management of waste within the city.
Prior to Lokoja becoming the state capital in 1991, it had population that was below 40,000 and by 1991 it increased to 61,784 (Kogi State Ministry of Budget and Planning). However at present, according to the 2006 census declaration, over 196,643 persons now inhabit the city (National Population Commission, 2006) in (Alabi, 2011). The underscoring factors of this population explosion include amongst other factors; the city’s geographical location that portrays it as a nodal town thereby making it witness massive influx of both resident and transit migrants; the city’s proximity to the Federal Capital Territory (FTC) as well as the city being a connection point between the southern and northern parts of the country. The implication of this therefore manifests in daily accumulation of solid wastes which are already common sights within the city; its associated health and environmental hazards as well as its aesthetic depletion.
In Lokoja, and all of Kogi State, solid waste management is solely undertaken by Kogi State Sanitation and Waste Management Board (KSSWMB) which apparently seems helpless to organize adequate and prompt collection and safe disposal of waste within the city in the face of steady overwhelming population growth (Uzondu, 2012).
The complexity of growth in Lokoja in relation to its inhibiting factors has equally complicated the problem of prompt evacuation of solid waste within the city. Meanwhile, waste collection and transportation, a vital aspect of waste management is the contact point between the waste generators (residential, commercial and industrial establishments) and the waste management system. This relationship needs to be carefully managed to ensure an effective system as the environmental impact caused by municipal solid waste demands special social and environmental attention (Siddam, Khadikar and Chitade, 2012). However, how this contact point can be efficiently managed in Lokoja has not been studied. Equally, in reality, there, are no provisions for standard waste collection (dumpsters) facilities in the city except the only recently improvised drums. The drums get filled up in no time owing to their limited sizes and spread to litter the immediate environment thereby further worsening environmental condition.
With the absence of these standard dumpsters, the residents of the city resort to dumping of waste on open plots, abandoned buildings, river banks, drainage channels, road divides, etc. These wastes often eventually dissipate into water body especially river Niger and pose series of health risks to the people who use the river for domestic purposes around Sintaku, Kpatakpoli, Icheu
This practice of indiscriminate dumping of MSW has the potential of giving rise to water and air pollution, green house gas emission and may give rise to other gases that cause serious problems to the human health and environment (Remigios and Wiseman, 2012). The upsurge in MSW recently has tasked the environmentalists to conceive various management practices that one could engage in while managing waste. Several management in the past and present include open dumping, burning, scavenging, separation, recovery, storage, evacuation and recycling. Pivotal to the aforementioned management practices is collection and transportation of MSW to places where these respective management practices could be enhanced. This prompt transport or movement of MSW however, could only be ascertained if MSW bins are strategically located where they could swiftly and promptly be evacuated. Several related works like Aremu (2012), employed GIS for finding the optimum location of municipal solid waste bins in parts of Ilorin. He was able to establish some optimum points of waste bin location but his work was silent on how to access the location of bins for waste evacuation to the approved sites. Equally, the work of Anifowose, Omole and Akingbade (2011) was on waste disposal site selection using Remote Sensing and GIS for Akure and environs. They identified potentially suitable sites for landfill after buffering the environment. However, little or nothing was said by them on the efficient routes for transporting waste from Akure environs to the identified landfills. Ogwuche (2013), in almost a related way to Anifowose, Omole and Akingbade (2011), employed GIS in determining spatial location of dumpsite and scheduling in Bauchi, Nigeria. He identified disposal method in place, data on solid waste generation, and schedules for households and the dumpsites in the area. However, his work fails to identify how to evacuate waste from the identified indiscriminate dumpsites to areas designated for waste disposal using optimized routes. In addition, Thompson, Afolayan and Ibidunoye (2013) developed a system that enhances waste management in planning and combating the menace of improper solid waste disposal by allocating and relocating of bins. In a like manner, their work does not incorporate effective collection means of waste from located and relocated bins. Babalola and Busu (2011) apply GIS for selecting landfill site in Damaturu by combining Analytic Network Process used in determining relative importance of weights of factors like land suitability. Transporting waste to the identified appropriate landfill was not discussed.
From these related works, GIS was used to identify suitable sites of dumpsters, landfills but fails to integrate transport system, a vital aspect of waste management into the works. It is therefore apparent that appropriate locations of dumpsters as well as best route ways for transporting evacuated waste have not been fully studied in Lokoja, Nigeria. It is this gap in knowledge that motivates this research work.
1.3 AIM AND OBJECTIVES
The aim of this study is to develop an effective waste collection and disposal system in Lokoja metropolis, Kogi State, Nigeria.
In a bid to achieving this aim, the following objectives would be painstakingly pursued. They are as follows, to;
- Assess the state of Municipal Solid Waste Management in Lokoja Metropolis.
- Examine problems of collection and disposal of Municipal Solid Waste in
- Identify important criteria for locating waste collection sites in a cost effective manner.
- Identify optimal routes for MSW collection and disposal points in Lokoja.
1.4. THE STUDY AREA
1.4.1. GEOGRAPHICAL LOCATION
Lokoja is located within latitudes 7° 45′ N and 7° 51′ N and longitudes 6°41’E and 6°45’E. It is the administrative headquarters (Capital) of Kogi State situated at the confluence of the Niger and Benue rivers within the lower Niger trough with an estimated area of 63.82 sq km(Figures 1 and 2). It serves as the gateway to the north and the south of Nigeria. The status of Lokoja as an administrative headquarters of Kogi State brought some institutions like the Federal University Lokoja, Kogi State Polytechnic, the Federal Medical Centre, Kogi State specialist hospital and a host of other institutions in the city.