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Tuesday, December 11, 2012

Municipal Solid Waste Management In Developing Countries (Part II)



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Waste Generation Characteristics

The importance of waste characteristics (both quantities and composition) on the design and selection of waste collection equipment cannot be overestimated. Some of the reasons why waste characteristics vary so much as observed by United Nations Human Settlements Programme (UN-HABITAT), 2010 include: 
  • Cooking and eating habits:  In some countries, the shops sell mostly food that has largely been prepared, either frozen or canned. In other countries and in smaller communities, poultry is purchased alive and vegetables are bought with considerable extra material in addition to the part that is consumed (maize is a good example). If fruit and vegetables are cheap and plentiful, and are often damaged when being transported, large amounts may be discarded. Different types of fruit and vegetables generate different amounts of waste – compare bananas and watermelons for example. 
  • Social and economic factors: Differences in lifestyle can be big, even within one city. This not only affects the type and amount of kitchen waste that is generated, but also the amount of paper (because of higher literacy and the purchase of newspapers and magazines). More affluent citizens are more likely to discard durable items (such as used clothing and electrical equipment) as they become obsolete, instead of repairing them. 
  • Recycling and reuse: In some towns much of the waste is fed to livestock and poultry. Food and drinks containers may be reused for household purposes. Certain items may be segregated from the waste and sold. Waste pickers may sort through wastes, taking out what they can use or sell. Such practices can have a major influence on the waste that is put out for collection. 
  • Architecture:  In cities where the housing is constructed mainly of mud brick and the floors and courtyards are not paved, there are large quantities of soil and dust in the waste. Sweeping of unpaved roads also increases the amount of soil in the waste. The lack of adequate toilets may increase the amount of excreta in the waste. 
  • Climate and geography: Heavy rainfall increases the moisture content of solid waste stored in the open. In tropical climates large amounts of vegetation can be expected in the waste, and seasonal climates may result in huge piles of leaves during certain times of the year. Some cities accumulate large quantities of fine windblown soil. The climate also influences the types and yields of crops, and therefore the food wastes generated by residents, e.g. sugarcane waste in countries where vendors sell cane juice on the streets may result in huge amounts of crushed cane during certain seasons.
The characteristics of municipal solid waste are also influenced by the definition of the term. In some situations, construction and demolition debris may be included with domestic and institutional wastes, and this inclusion can have a significant influence on the overall weights and characteristics of the waste that is collected.
To this point, one can examine several issues related with municipal solid waste generation

Issues Related With Municipal Solid Waste, MSW Generation

municipal solid waste management
a) Non-point source: There are different sources which generate the Municipal solid waste in large quantities which is difficult to manage. Any place where human activity is involved finds solid waste. Waste is generated in the form of vegetable remaining & food waste, used plastic bags, plastic containers/ bottles, from residential area. During celebration of different festivals & events, such waste is generated in significant quantity. Due to urbanization & population growth, many construction activities are seen in recent years resulting into creation of construction/ demolition wastes or debris. To give an example, if the external surface of a building of 20 floors is repaired, the waste generated would be nearly 200 truckloads. One can imagine how much construction debris is generated in recent years. Industries are one of the major sources of MSW generation, this sector generate wastes from activities like raw material packaging, transportation, final product packaging, indisposed defective product etc. Workers working in such sectors also contribute to waste generation through office stationeries, paper. Offices, Commercial Complex, Industries, Educational Institutes, Residential complexes generate overall wastes in remarkable quantities.
b) Attitude: People at large don’t care about waste and so never take efforts to dispose it properly. Waste generation is mostly related with attitude of society towards it. In developed countries people are aware about how to minimize generation of waste. Limited population makes it simple for them. In developing countries particularly with large population things become difficult.
c) Impacts: When the waste is dumped, because of its composition it does not decompose very quickly, making space unavailable for other waste. Given below are some examples to understand how much time it takes for various materials to decompose.

Type of litter Approximate time it takes to degenerate the litter
Organic waste such as vegetable and fruit peels, leftover foodstuffs, etc. a week or two
Paper 10-30 days
Cotton cloth 2-5 months
Wood 10-15 years
Woolen items 1 year
Tin, aluminum, and other metal items such as cans 100-500 years
Plastics one million years
Glass, bottles Undetermined


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