n et al. (  ) observed that waste is disposed of in unauthorized waste dump sites in seven urban centres of Gilgit-Baltistan (GB) in Pakistan, despite having officially designated dump sites. This clearly demonstrates either the inability of authorities to curtail the problems adequately or the deliberate negative attitude of the people in not complying with the waste management agencies. The authors of this present study agree with both the two assertions because a common problem for MSW management in most Nigerian cities includes institutional deficiencies, inadequate legislation, resource constraints and improper disposal of trash by the residents, which is a form of illegal dumping.
2.2. Waste Collection Strategy in Nigeria
The practice of disposing of solid waste indiscriminately is costly in terms of collection, transportation, disposal and recycling. Figure 1 illustrates the common practice of solid waste disposal in Kano municipal. From the figure, the major source of solid waste in Kano is categorized into households, commercial, industrial, institutions and street refuse. Waste collection and transportation implies to the system of waste collection from source to disposal sites. Typically, wheelbarrows are used for collecting and transporting solid waste to dump sites from households and marketplaces, and neighborhoods where trucks cannot access. The wheelbarrows usually discharge at a point (intermediate points) where trucks (about 7 tons capacity) collect it for eventual transportation to the final disposal sites/landfills.
Kano’s waste can be categorized into street refuse, urban livestock manure, and industrial or semi-industrial wastewaters  . Malumfashi et al.  noted that the sources of street refuse in Kano are households, markets, drainage clearance, and street sweeping, which are mostly found at the side of the street
Figure 1. Schema of solid waste disposal practices in Nigeria.
and on both authorized and unauthorized dump sites. For example, the free roaming of livestock particularly in the ancient city of Kano directly contributes to the huge pile of street refuse in the city. Malumfashi et al.  further disclosed that industries in the metropolis are the sources of liquid and gaseous waste. Many studies have highlighted the significance of offal discharge (domestic and industrial wastes) into the drainage systems and streams around the metropolis to the source of surface water pollution within the metropolitan Kano (see, for example,  ).
3. Study Area, Materials and Methods
3.1. Study Area
Kano is the administrative centre of Kano state and the third largest city in Nigeria after Lagos and Ibadan. Kano metropolis is located between latitudes 11˚52'N and 12˚07'N and longitudes 8˚24'E and 8˚38'E. It is relatively at the centre of Kano state (see Figure 2). Kano state has a population of approximately
Figure 2. Metropolitan Kano.
more than 10 million  . The demographic expansion of Kano was as a result of its good fertile landscape, commercial city, as well as its accessibility and hospitality. The metropolitan Kano has a population of more than 4 million and is the major trading hub of Northern Nigeria  . Similarly, the modern Kano metropolis is a conurbation of eight Local Government Areas (LGAs) around the main city, which metamorphose to form the present Kano metropolis. The LGAs are Dala, Fagge, Gwale, Kano Municipal, Nassarawa, Tarauni, Kumbotso and Ungogo. These eight LGAs formed the study area for this study.
3.2. Data Sources
Data for this study comprises both primary and secondary sources as follows: the primary data consists of about 300 waste disposal sites collected using Garmin handheld GPS from the eight LGAs within the metropolis. The secondary data consists a high-resolution QUICKBIRD imagery for 2014, topographical map of metropolitan Kano, at 1:5000 scale (obtained from Kano state ministry of Land) and solid waste disposal type and collection schedule from REMASAB.
The schema of the methodology used for this study is presented in Figure 3. From Figure 3, the QUICKBIRD satellite image was handled in Erdas Imagine 11 software for Geometric and Radiometric Correction. ArcGIS 10.2.1 was used in the geometric correction of the topographical map as well as the creation of a simple database (using the location data of the waste disposal sites collected) and shapefiles for the entire project. The various data were then imported into ArcGIS, and using an overlay procedure, a spatial distribution map and other spatial analysis for the entire metropolis was achieved. The results are presented in the form of maps showing the locations of the entire disposal sites on the land use pattern of the metropolis.
Figure 3. Flow chart of the methodology.
4. Result and Discussions
4.1. Distribution of Existing Solid Waste Disposal Sites in Kano Metropolis
The various locations of the existing solid waste disposal sites are displayed in Figure 4. From Figure 4, most of the disposal sites are not properly located considering the environmental and social well-being of the people as suggested by Rahman et al.  . The figure further showed that more than 80 percent of the existing disposal sites are within the range of 30 to 50 meters distance from road networks and are therefore considered not properly sited. Nonetheless, the result of the status of waste disposal sites within the study area (Figure 5) suggests that less than 12 percent of the disposal sites are unauthorized.
This finding is contrary to the initial view of the researchers, whose preliminary investigation of the disposal sites prior to the actual study suggested that majority of the sites are illegal. Similarly, it was observed that the concentration of waste disposal sites decreases from the city centre as one move outwards. This was connected with the high concentration of economic activities and population in the city centre compared to the outskirts of the metropolis. This position was earlier put forward by Lancelet and Nija  , whose study also confirmed a strong relationship between waste generation and concentration of population
Figure 4. Distribution of solid waste disposal sites in the study area.
Figure 5. Status of solid waste disposal sites in Kano Metropolis.
and economic activities in Thodupuzha municipality, Idukki district of Kerala state in India. Overall, unauthorized waste disposal sites constitute significant problems of many local authorities particularly in the suburbs or large urban areas of the developing countries. It is also our position that it is an environmental crime to illegally dispose of on public or private open plots or even discharged in the drains or water bodies, which may result in clogging of drains, pollution of water resources and increase in unsanitary conditions of the urban areas.
4.2. Situation of Solid Waste Disposal Sites in Kano Metropolis
Open dumpsites in developing urban cities are characterized by indiscriminate waste disposal. They are uncontrolled and therefore pose major health threats, which affect the landscape of urban cities   . The findings of this study identified that about 93 percent of the 300 existing waste disposal sites investigated are open space dumping and only about 7% are collected in a container (see Figure 6 and Table 2 for an illustration). This conformed to the earlier assertion of UNEP  , which highlighted that in most developing countries, open dumping is the norm in terms of waste disposal. However, it should be noted that the open dumpsite method is a primitive stage of solid waste management in many parts of the world. It is considered as one of the most poorly rendered services by municipal authorities in developing countries as the systems applied are unscientific, outdated and inefficient  . The waste is often dumped indiscriminately on open plots of land and particularly on streets (refer to Figure 6 and Table 2 for more details). This method is based on “throwaway culture” where wastes are disposed into the nearest open space, on land or surface water without environmental consideration  . Foday et al.  referred this to as “not in my backyard syndrome” where the waste is merely transferred from one location to another location where its nuisance value is perceived to be less.
Table 2. Status of some selected waste disposal sites in Kano Metropolitan.
Figure 6. Open space dumping and container ((a)-(e) are open space dumping, while (f) is a container dumping site).
As highlighted in Table 2, there are various sizes of waste disposal sites within metropolitan Kano. The smaller areas range approximately between 9 m2 (mainly containers) and 500 m2 (mainly open space) (refer to Figure 6), while the larger ones range between 2000 m2 and 120,000 m2 (refer to Table 2 for more details). As pointed earlier, these solid waste disposal sites are found both within and outskirts of the Kano municipal. Certainly, with the current global population increase and the rising demand for food and other essentials, there has been a rise in the amount of waste being generated daily by households. These wastes are thrown into municipal waste disposal sites and due to poor and ineffective management, the dump sites turn to sources of environmental and health hazards to people living within the vicinity of such sites. One of the main aspects of concern is the pollution caused to the earth, be it land, air and water  . It is worth noting that the situation in Kano municipal is not different from most cities in the developing countries. For example, most cities in the developing countries face serious environmental degradation and health risks due to their inadequately developed municipal solid waste management system. In Nigeria, despite the numerous policies and regulations on solid waste, the country remains one of the largest producers of solid waste in Africa and solid waste management is assuming alarming proportions  .
5. Policy Implications, Conclusion and Recommendation
5.1. Policy Implications
Solid waste disposal and management services are public services, in which the local authorities or respective municipal agencies should be responsible for its delivery. Even though private and individuals are involved in this task, it is imperative that municipal authorities should remain in charge of this task in order to achieve an overall metropolitan-wide consistency in solid waste management success. Similarly, private enterprise should be encouraged to participate more under appropriate conditions, to provide similar services provided by the public authorities. It is also important that the authorities should involve all stakeholders (private waste collectors, citizens, industries, academicians and various governmental and non-governmental environmental organizations) whenever it is planning for its solid waste management schemes.
The study used remote sensing satellite data and GIS in understanding the spatial distribution of existing waste disposal sites in Kano metropolis. The results of the study have shown that most of the waste disposal sites are not properly located because much consideration is not given to the environment and social implications of the current trend. It has also been noted that the distribution of solid waste disposal sites is related to the number of economic activities present in a particular area. That is why the disposal points are numerous at the centre of the metropolis compared to other places.
It should also be noted that the Kano state government has an agency (REMASAB) that supervises the activities of waste generation and collection; and a policy that encourages an end of month sanitation exercise that is aimed at cleaning the city. This paper suggests that the activities of such agency should be reviewed periodically in order to address the issue of illegal dumping of waste in areas that do not conform to the standards. Similarly, measures should be put in place to step up more stringent policies of waste dumping violation. The present policing of the performance of the policy programmes are inadequate because there is no recourse for periodic checks of the aftermath in order to assess the success or failure of the programmes. The lack of these periodic checks has resulted in the failure of most programmes in the country.
This paper suggests a further detailed research on the suitability assessment of the existing solid waste disposal sites, refuse collection, disposal and management in order to address the problem systematically. This is crucial because many diseases are a waste and refuse related, which can easily be spread out from the disposal or dumping sites.
This research was funded by the Nigerian Tertiary Education Trust Fund (TETFund). The authors also wish to acknowledge REMASAB staff for their cooperation during field investigation.
 Sha’ Ato, R., Aboho, S.Y., Oketunde, F.O., Eneji, I.S., Unazi, G. and Agwa, S. (2007) Survey of Solid Waste Generation and Composition in a Rapidly Growing Urban Area in Central Nigeria. Waste Management, 27, 352-358.
 Babatunde, B.B., Vincent-Akpu, I.F., Woke, G.N., Atarhinyo, E., Aharanwa, U.C., Green, A.F. and Isaac, J. (2013) Comparative Analysis of Municipal Solid Waste (MSW) Composition in Three Local Government Areas in Rivers State, Nigeria. African Journal of Environmental Science Technology, 7, 874-881.
 Tirusew, A.E. and Amare, S.M. (2013) Solid Waste Dumping Site Suitability Analysis Using Weighted Geographic Information System (GIS) and Remote Sensing for Bahir Dar Town, North Western Ethiopia. African Journal of Science and Technology, 7, 976-989.
 Singh, G.K., Gupta, K. and Chaudhary, S. (2014) Solid Waste Management: Its Sources, Collection, Transportation and Recycling. International Journal of Environmental Science and Development, 5, 347-351.
 Rahman, M.D., Mujibor, K.R.S. and Ahasanul Hoque, M.D. (2008) Suitable Sites for Urban Solid Waste Disposal using GIS Approach in Khulna City, Bangladesh. Proceedings of the Pakistan Academy of Sciences, 45, 11-22.
 United Nations Environment Programme (UNEP) (n.d.) Solid Waste Management.
 Hansen, C. (2015) Solid Waste Management in Nigeria. BioEnergy Consult, Powering Clean Energy Future.
 Bakare, W. (2016) Solid Waste Management in Nigeria. BioEnergy Consult, Powering Clean Energy Future.
 Agboje, I.A., Adeoti, A. and Irhivben, B.O. (2014) Performance Assessment of Solid Waste Management following Private Partnership Operations in Lagos State, Nigeria. Journal of Waste Management, 2014, 1-8.
 Kawai, K. and Tasaki, T. (2016) Revisiting Estimates of Municipal Solid Waste Generation per Capita and Their Reliability. Journal of Material Cycles and Waste Management, 18, 1-13.
 Malumfashi, S.L., Muktar, M. and Adamu, Y.M. (2011) Constraints to Waste Management in Kano Metropolis, Northern Nigeria.
 Hussain, A., Begum, S., Hussain, S.W., Khan, Z. and Ali, A. (2016) Analysis of Management and Environmental Effects of Municipal Solid Waste Due to Inefficient Practices through People’s Perception in Gilgit City, Gilgit Baltistan, Pakistan. International Journal of Scientific Research in Environmental Sciences, 4, 12-16.
 Gilgit-Baltistan Environmental protection Agency (GB-EPA) (2013) Quantities and Characteristics of Solid Waste in Seven Urban Centers of Gilgit-Baltistan (GB), Gilgit-Baltistan Environmental Protection Agency, Pakistan.
 Mustapha, A. and Ahmad, H.I. (2017) Hydrochemistry Assessment of River Water Quality Variations in a Highly Heterogeneous Land Use Area along River Kano. Northwest Journal of Social and Management Sciences, 1, 54-71.
 National Population Commission of Nigeria (NPC) (2009) 2006 Facts and Figures.
 Foday, P.S., Xiangbin, Y. and Quangyen, T. (2013) Environmental and Health Impact of Solid Waste Disposal in Developing Cities: A Case Study of Granville Brook Dumpsite, Freetown, Sierra Leone. Journal of Environmental Protection, 4, 665-670.