Design of an Efficient Solid Waste Management and Disposal Scheduling System: A Case Study of Enugu Metropolis
Chapter One
Objectives of the Study
The main objective of this research work is to design an effective waste management system that will reduce the operational cost of ESWAMA and improve its waste disposal efficiency. These specific objectives are:
- To establish nine more landfill sites other than the former one at Ugwuaji which will help to reduce the long distances travelled by the
- To develop a solid waste disposal schedule that will minimize cost of transporting the waste generated in the metropolis using a mathematical
- To compare the result with the existing schedule with respect to efficiency and
- To suggest the use of other waste management methods that will help to reduce the quantity or volume of solid waste that go into the landfill.
CHAPTER TWO
LITERATURE REVIEW
Different Approaches to solving solid waste Management problems.
Solid waste management is borne out of the desire to control environmental
pollution with its attendant health hazards and this had stirred up great researchers (foreign and indigenous) to write on waste management. According to Smith S.E (2011), solid waste management is a polite term for garbage management. As long as humans have been living in settled communities, solid waste, or garbage, has been an issue, and modern societies generate far more solid waste than early humans ever did. Daily life in industrialized nations can generate several kilograms of solid waste per consumer, not only directly in the home, but indirectly in factories that manufacture goods purchased by consumers. Solid waste management is a system for handling all of this garbage; municipal waste collection is solid waste management, as are recycling programs, dumps, and incinerators.
From the definition in BusinessDictionary.com, Solid waste management is a systematic control of generation, collection, storage, transport, source separation, processing, treatment, recovery, and disposal of solid waste. In the world today, many countries approach solid waste management problems differently due to the kind of wastes they generate and the type of waste management equipment available in their countries. Therefore, a broad literature is available on studies that deals with different methods used in solid waste management. Some of these literatures according to Toochukwu, O.C (2005) includes: Optimisation of solid waste collection system Agunwamba, J.C (2003), fleet and truck size selection (Ojiako and Nwosu, 1989), Solid wastes: Engineering Principles and Management Issues (Tehbanoglous et al, 1997), Waste generation and Management in a depressed Economy (Odocha, 1994). Other ones are Integrated Solid waste management (MacDonald and Vopni, 1994), Vehicle routing and Optimisation of solid waste collection routes (Chang, et al, 2002) etc. Solid Waste management practices differ for developed and developing nations, for urban and rural areas, and for residential and industrial producers. It is commonly observed that in most third world countries like Uganda, Nigeria (Enugu state) etc, are still battling with the problem of being able to evacuate or dispose all the solid wastes generated daily in their environment, while developed countries like America, Great Britain, Japan and Germany are researching on how to recover all the useful things from their solid wastes. In support of the above statement, Anupam Khajuria et al. (2010) stated that the common problem faced by all developing Asian countries, is the disposal of municipal solid waste and availability of land fill site area. Based on the above statement, it is quite understandable that the waste management approach will be different for the two groups of countries.
This section will present some review of relevant literatures on approaches to solving waste management problems under the following sub-headings:
- Fleet and Truck size Selection
- Minimization of solid waste management
- Integrated or combined solid waste
Fleet and Truck size
Wood (1986) had examined selecting the right vehicle for collection operation as the best way of optimizing the collection problem by considering these factors like total weight, length, and types of collections and operators productivity. Orjiako and Nwosu (1989), proposed a mixed integer-programming model to balance the crew size and the number of vehicles. The mixed integer-programming model was solved using a simplex algorithm instead of the branch and bound method. The model lacks the features of a modern crew selection method. According to Robert M. Clark (1972) collection of solid waste is much more expensive than its disposal. Most municipal collection fleets are made up of packer trucks that service areas with dissimilar topography, population density, and waste generation rates. When vehicles are selected for solid waste collection fleets there is usually very little consideration given to providing the required service at minimum cost. One possibility for minimizing collection costs is to select a fleet of various-sized packer trucks, while simultaneously satisfying the service constraints. To illustrate this approach, the waste collection system of a large metropolitan area is analyzed for proper fleet size and type of packer vehicle. Selection of the optimal fleet size and type of packer truck is formulated and solved as a linear programming problem.
Agunwamba, J.C (2003), did an excellent work on optimization of solid waste collection system in Onitsha, Nigeria. His focus was on the optimal combinations of collecting vehicles, containers and their distributions in each zone, which will ensure efficient collection at minimal cost. The work considered how best to assign different types of vehicles and containers to the six zones of Onitsha such that the waste disposal will be efficient and at a minimal cost. The problem was formulated as an integer problem with a cost objective function and constraints. The solution to the optimization problem formulated from the data collected was obtained using TORA Optimization System. His result showed that the existing distribution and combination of waste collection vehicles require alteration in order to achieve optimality. His optimality cost for effective and regular collection of waste was N 21,039,512.50. In the case of Enugu state, one type of vehicle is being used for waste collection in the metropolis (see appendix 5, 6). The table 2.1 shows one of his optimal tables.
Another excellent work on solid waste management was done by Otti (2010). His research paper was on a model for solid waste management in Anambra State, Nigeria. His research was aimed at determining which type of integrated solid waste management option or programme will be used to implement minimized cost and maximized benefit (benefit cost ratio) over a long period of planning period. He applied a linear programming model that takes into account the scheduling decision, benefit Over-time, budget constraints and constraints on the number of equipment available to effectively implement the project. According to Tomas et al (1979), Linear Programming is an objective function that optimizes cost or gain as it is subjected to the constraints and involves some decisions. His work also contains many innovative features and removes many limitation frequently encountered in most existing optimization modeling for waste management. His optimality cost for effective and regular collection of waste for Anambra state is N 426 Million = USD 2.84 Million.
CHAPTER THREE
MATERIALS AND METHOD.
Data
The data used in this research work were collected from both primary and secondary sources. Some tools of participatory appraisal techniques namely direct observations, semi- structured interviews, questionnaires and literature reviews were all employed. Direct interview method was used to obtain information from ESWAMA staff (table 3.3- 3.5) and NPC staff (table 3.8), while the questionnaire in appendix 55 was administered to some of the inhabitants of the ten zones in the city. Tables (3.6) and (3.7) show the summary of the questionnaire. Table 3.9 depicts the amount of waste generated in the metropolis.
In addition, a purposely-organized field tour to all the ten zones in the metropolis was carried-out. Pictures in appendix 3-53 excluding appendix 41 were taken during each trip to determine the level of waste accumulation in the metropolis. Some important census data were collected from the National Population Commission (NPC), Enugu office. These data were used to determine the population of Enugu metropolis and the average amount of solid waste generated there. Google was used to get the map and road network of Enugu metropolis. From this map in figure 3.1 the nine new landfill sites were proposed based on areas that favours the conditions needed before citing a landfill site. Also, the centre for each zone was chosen by observations and the average distances from each zone (centre) to each landfill site (table 3.1) were determined by measurement (using the scale: 1:35000cm on the map) along the road.
The numbers of ESWAMA dumpsters along the streets of the metropolis were obtained from the ESWAMA operation unit (table 3.5). The average maintenance costs of the compactors for one year were also obtained from the Maintenance Department. The ten zones of which Enugu metropolis were divided into were also obtained from the ESWAMA Operation Unit.
CHAPTER FOUR
RESULTS AND ANALYSIS
Table of Results
The final result of the iterations obtained from chapter three for the land fill site and their corresponding zones is presented in table 4.1 as shown below:
CHAPTER FIVE
Conclusion and Recommendation.
Conclusion
The management of solid waste is a herculean task as wastes are being generated by human activities, animals and plants on every passing minute. However, an attempt had been made in this work to present an efficient method for handling solid wastes in a metropolis ( Enugu metropolis).This design if correctly applied is capable of reducing the total cost of waste disposal in the metropolis under study by 52%.
These research findings are recommended to ESWAMA in particular and to any other organization with similar type of business. This methodology can easily be adapted to other state of the federation in taking care of their solid waste management, even though the original design was applicable to Enugu state waste management Authority.
Some of the specific recommendations are thus:
- ESWAMA should purchase additional twenty (14) compactors as this will help to evacuate the solid waste generated in the metropolis each
- ESWAMA should maintain the five Trips arrangement per day for an efficient disposal of the solid wastes generated in the metropolis each
- ESWAMA should purchase additional three thousand three hundred and eighteen (3318) Dump sters to augment the nine hundred and thirty (930) dump sters already in use.
- ESWAMA should establish nine (9) more landfill sites in addition to Ugwuaji landfill site.
- ESWAMA should establish a branch office in each zone where the compactors will take off
- From the annual saved cost of N22, 974,826.45, the agency can construct nine additional landfill sites at the cost of N6, 300,000; buy four compactors (N10, 400,000) recruit four drivers (N 1,440,000) and twelve crew men (N 2,880,000) which amounts to N 21,020,000 leaving an excess of N 1,954,826.45 that can be used for miscellaneous expenditure such as site maintenance.
- ESWAMA should use a differentiated coloured solid waste buckets placed at different locations with each bucket specified for a particular function. For an example, a red coloured waste bucket should contain radioactive or poisonous waste, green coloured bucket should contain biodegradable waste while yellow and white buckets should contain combustible waste and recyclable wastes
Suggestions for Future Research
In light of the above analysis, it is important to suggest that future work can be carried out to improve the efficiency of ESWAMA.
- A good research work should be done on designing and constructing a recycler that can convert the wastes disposed in the landfill site into useful end
- Direct energy recovery converter such as digesters, bio-gas burners etc., that are affordable to low income earners should be researched upon to aid the preventive mechanism of waste
- The concept proposed by Guido Maria Bazzani (1998) as shown in figure 2.2 should be researched on since it can enhance efficient solid Waste management of the
- Also a good research work should be done on designing an efficient solid waste disposal scheduling system where differentiated coloured solid waste buckets placed at different locations with each bucket specified for a particular
REFERENCES
- Agunwamba, J.C, (2003).Optimization of Solid Waste collection system in Onitsha, Nigeria: International Journal of Environmental Issues, Vol No 1, page 124- 126.
- Ajagbe, W.O, Agbede, O.A,(2004). Solid waste Management in South-Western Nigeria: International Journal of Environmental Issues, Vol 2 No 1&2, page 92-100.
- Aliyu Baba Nabegu (2011). Solid Waste and Its Implications for Climate Change in Nigeria Department of Geography, Kano University of Science and Technology, Wudil,Kano, Nigeria.
- Andrew Jones(2003). What Is Integrated Waste Management? wiseGeek conjecture corporation.pp-1
- Anupam Khajuria, Yugo Yamamoto and Tohru Morioka.( 2010) .Estimation of municipal solid waste generation and landfill area in Asian developing countries
- Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering,Osaka University, 2-1 Yamada-oka, Suita, Osaka – 565-0871, Japan.
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- Ayaji, Kenneth (2008). A semi-structured interview administered to the ESWAMA Officials.
- Chang, N.B., and Wei Y.L. (2002). “comparative study between heuristics waste algorithm and optimization technique for vehicle routing and scheduling in the solid management system.,” civil Engineering and Environmental system, vol.19,No 1,41-65.