Before undertaking solid waste management, it is essential to have some knowledge about the solid waste materials that are normally encountered. Generally, solid waste materials are classified into two broad categories:
1. Household solid waste, and
2. Commercial waste.
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Generally, household solid materials are collected locally and the amount depends upon the size and consumption habits of the population. It is disposed off on either public property or private contractors’ sites. Commercial wastes are generated by commercial establishments but are usually disposed of by public facilities. Industrial wastes are those generated by manufacturing firms.
A detailed classification:
The detailed statistics for the generation and disposal of wastes are not available for developing countries. The typical analyses of some of the waste materials discharged at Kanpur, Calcutta and Nagpur are another study carried out by Bhide et al, on refuse in Indian cities, is In this case, the classification has been done on the basis of population.
The effect of population on the composition of solid wastes is obvious; for example, paper, rubber and leather, plastics, metals and glass increase with the increased population of the city. The total compostable matter also increases with the size of the city. A similar study carried out in Nigeria, another developing country, by Oluwande.
The figures available from the United States indicate that 10 lb of waste per capita per day is generated. But only 5.12 lb per day per capita is collected. It is common practice for each household in the US to burn a large proportion of its rubbish in a back-yard incinerator. Mainly food scraps, bottles and unburnable articles are collected. This is, of course, socially undesirable.
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In the United States, the growth rate between 1922 and 1965 was about 1.2 percent but a growth rate of 1.4 percent was expected for the period 1965 to 1980.
The selected components of solid wastes, by weight, for some of the important countries/cities, are given a clear scrutiny of the composition, both in developing and developed nations, clearly indicates that the percentage of paper, rubber, leather, plastics, metals and glass increases considerably with increasing industrialization due to wide application of these materials in day-to-day life.
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