7 CONCLUSIONES Y RECOMENDACIONES
TEST DE PENSAMIENTO LÓGICO (TOLT) DE TOLBIN Y CARPIE
Management is a dynamic process and it cannot be limited to a place, time or area(Ezigbo, 2012). Its process involves setting objectives and developing plans to achieve them, implementing the plan through leadership and controlling, and appraising performance against previously set standards(Koontz and Donnel, 1980). Tchobanoglous et al(1993) defined waste management as the discipline associated with the control of generation, storage, collection, transfer, transport, processing, and disposal of waste in a manner that is in accordance with the best principle of public health, economics, engineering, conservation, aesthetics, and other environmental considerations, and that is also responsive to public attitudes.
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Rodgers(2011) defined SWM as a systematic control of generation, storage, collection, transportation, separation, processing, recovery and disposal of solid waste. In the smallest of places, SWM is accepted as a major aspect of the indigenous community organization and traditional home management; hence every house/compound has a designed area for solid waste collection/disposal and or incineration(Sanda, 2008). Among the most crucial environmental challenges facing developing countries is the municipal/urban solid waste. Cointream(1982) defined municipal solid waste (MSW) as non-air and sewage emissions created within and disposed of by a municipality, including household garbage, commercial refuse, construction and demolition debris, dead animals, and abandoned vehicles. And the Department of Environmental Quality Promotion(2002) pointed out that the majority of substances that make up MSW include paper, vegetable matter, plastics, metals, textiles, glass and rubber.
2.6.2.1 Solid waste management techniques
The stages involved in waste management are depicted in Figure 5.
Generally, management of domestic, industrial and commercial waste consists of collection and disposal of the generated waste.
1. Waste Generation: This is building up of discarded materials after the usefulness has been taken from the original products. At present, waste gene- ration is an activity that is yet to be well controlled by man.
2. Waste Collection: This entails both gathering/picking up and hauling of the discarded materials to a location where the collection vehicle is emptied. The unloading of the collection vehicle is also considered part of the collection operation (Tchobanoglous et al, 1993)
Generation
Storage Collection Transportation
Treatment Disposal
Figure 5: A flow chart showing the stages of a waste management system
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i. The hauled-container system: In this system, the waste containers are hauled from the collection point to the final point of disposal, processing facility or trans- fer station. In this system, the collection vehicle empties just one container per trip. In other words, the number of trips equals the number of container locations(Sincero and Sincero, 1996).
ii. The stationary-container system: This system involves emptying the waste container directly into a collection vehicle at the point of collection. There are two types in this system: a) large containers which must be emptied by mechanical means, and b) small containers which can be emptied manually(Sincero and Sincero, 1996). In this second system, the collection vehicle empties more than one container in one trip. Plates 2 and 3 in the Appendices show loaded waste containers waiting for a disposal vehicle(s).
3. Waste Transportation: This is one of the key components of waste manage-ment system. It involves moving the quantities of waste generated at one spot to an-other point of transfer or final disposal. Here various types of vehicles ranging from handcarts to modern mechanized vehicles are used. See Plate 4 of the Appendices.
4. Waste Treatment: This includes all techniques used in preparing and making a collection of waste materials safe for disposal. Rao(2008) presented the important steps in effective hazardous waste management to include the following:
i. Waste minimization
ii. Detoxification and neutralization of liquid waste streams by physical, chemical and/or biological means.
iii. Destruction of combustible hazardous waste in high temperature incinerators.
iv. Stabilization/solidification of sludge and ash from steps (ii) and (iii).
v. Disposal of treated residues in specially designed landfill
5. Waste Disposal: This includes all techniques and practices involved in getting rid of generated waste. Several methods of disposing waste include open dumping, sanitary landfill (controlled tipping), incineration and composting.
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2.6.2.2 Risks/costs associated with improper solid waste management
The poor state of SWM in urban areas (of developing countries) is now not only an environmental problem but also a major social handicap(Daskalopoulos et el, 1998). See Plate 5 in the Appendices. The indiscriminate and improper dumping of MSW is increasing and is compounded by a cycle of poverty, population explosion, decreasing standards of living, poor governance, and the low level of environmental awareness.
Rao(2008) opines that the relationship between solid waste and human disease is difficult to prove. However, improper solid waste handling is a health hazard and causes damage to the environment. It also brings about adverse effects on our environment and may also lead to poor health and well-being of our future generations. Improper management of wastes includes activities like inappropriate siting, design, operation, or maintenance of dumps and landfills. Some of the dangers in poor handling of solid wastes as pointed out in Teleke(2004) include:
i. Uncollected wastes often end up in drains, causing blockages which result in flooding and unsanitary conditions.
ii. Flies breed in some constituents of solid wastes, and flies are very effective vectors that spread disease.
iii. Mosquitoes breed in blocked drains and in rainwater that is retained in discarded cans, tires and other objects. Mosquitoes spread disease, including malaria and dengue.
iv. Rats find shelter and food in waste dumps. Rats consume and spoil food, spread disease, damage electrical cables and other materials and inflict un-pleasant bites.
v. The open burning of waste causes air pollution; the products of combustion include dioxins which are particularly hazardous.
vi. Aerosols and dusts can spread fungi and pathogens from uncollected and de-composing wastes.
vii. Uncollected waste degrades the urban environment, discouraging efforts to keep streets and open spaces in a clean and attractive condition. SWM is a clear indicator of the effectiveness of a municipal administration - if the provision of this service is inadequate large numbers of citizens (voters) are aware of it. Plastic bags are a
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particular aesthetic nuisance and they cause the death of grazing animals which eat them.
viii. Waste collection workers face particular occupational hazards, including strains from lifting, injuries from sharp objects and traffic accidents.
ix. Dumps of waste and abandoned vehicles block streets and other access ways.
x. Dangerous items (such as broken glass, razor blades, hypodermic needles and other healthcare wastes, aerosol cans and potentially explosive containers and chemicals from industries) may pose risks of injury or poisoning, particularly to children and people who sort through the waste.
xi. Heavy refuse collection trucks can cause significant damage to the surfaces of roads that were not designed for such weights.
xii. Waste items that are recycled without being cleaned effectively or sterilized can transmit infection to later users. Examples are bottles and medical supplies.
xiii. Polluted water (leachate) flowing from waste dumps and disposal sites can cause serious pollution of water supplies. Chemical wastes (especially persistent organics) may be fatal or have serious effects if ingested, inhaled or touched and can cause widespread pollution of water supplies.
xiv. Large quantities of waste that have not been placed according to good engineering practice can slip and collapse, burying and killing people.
xv. Waste that is treated or disposed of in unsatisfactory ways can cause a severe aesthetic nuisance in terms of smell and appearance.
xvi. Liquids and fumes, escaping from deposits of chemical wastes (perhaps formed as a result of chemical reactions between components in the wastes), can have fatal or other serious effects.
xvii. Landfill gas (which is produced by the decomposition of wastes) can be explosive if it is allowed to accumulate in confined spaces (such as the cellars of buildings).
xviii. Methane (one of the main components of landfill gas) is much more effective than carbon dioxide as a greenhouse gas, leading to climate change.
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