The quantity of municipal solid waste generated depends upon a number of factors such as food habits, the standard of living, degree of commercial and industrial activity.

'Municipal solid waste' includes wastes generated in residential and commercial areas; whereas wastes from industrial and agricultural operations are separately considered.

Various commercial establishments generate different categories of wastes depending upon the type of activity. Shops and other establishments generate waste containing a large amount of paper, straw, cardboard packing cases which are generally non-decomposable. Small commercial establishments may discharge the waste along with the municipal waste.

1. Street Wastes

In addition to the waste originating from premises, the waste from streets is also included in the municipal solid wastes. Street wastes fall into three main categories - natural, road traffic and behavioral.

• i) Natural wastes: These include the dust blown from unused land and roads, dead and decaying vegetation, seeds originating either from avenue or blown from marginal areas. It cannot be controlled as it originates from sources other than the streets.

• ii) Road traffic wastes: These originate from wear and tear of the road surface and that from transport vehicles. The motor vehicles while moving on the road deposit petrol, oil and at times, spill their contents on roads. In developing countries multiplicity of vehicles are in use including animal-drawn vehicles which often come from surrounding rural areas. These vehicles deposit mud, animal excrement, etc. on the road adding to the road traffic wastes.

• iii) Behavioural wastes: These originate from wastes thrown by pedestrians, or by persons using the streets and from wastes from adjoining houses, shops, and other premises which spill out due to improper storage. It also includes dried excrement of domestic animals which poses danger to the sweeping staff when the disease organisms become air-borne. Much of this waste can be prevented by a sustained health education program backed by suitable legislation and enforcement.

2. Urban Solid Waste

The quantity of urban solid wastes is known to vary seasonally. During festive occasions, the amount of refuse shows an increase, e.g., the rubbish generated during Diwali in India is considerably higher than in other seasons. During monsoon, tree and hedge cuttings have been recorded to be high. Quantity generated during winter and summer seasons also vary.

In industrialized countries, collection routes are well organized due to which variation in quantities can be identified. The situation is not so in developing countries, interpretation of the variation in daily quantities could at best be a guess.

3. Quantity at Disposal Site

The quantity of waste measured at the disposal site should not be relied upon as it would not represent the generated quantity. Absence of weigh-bridges at disposal sites is a common problem in developing countries. In such cases, the density of the waste multiplied by the volumetric capacity of the vehicles provide the weight of the wastes.

• Measurement of density: The refuse is collected in a small box from the refuse mass (from dustbin or truck or disposal site) weighed by a spring balance and emptied in a box of one cubic metre capacity.

4. Density of Refuse from different Countries

The density of refuse depends upon constituents such as organic content, inorganic content, paper, etc. In developing countries, the percentage of inorganics has been observed to be high. It is partly due to the fact that proper storage bins are not provided and street sweepings and ash tend to get collected along with the refuse. It is also a common practice to include street sweepings in the refuse, increasing the density.

Density value in India and other developing countries range from $ 300 \text { to } 560 \mathrm{kg} / \mathrm{m}^{3} $ (In Table Below) . In singapore, it is as low as 175 $\mathrm{kg} /$ . $\mathrm{m}^{3},$ while in Kathmandu and Dacca 600 $\mathrm{kg} / \mathrm{m}^{3}$ have been reported. In general the value is around $400-500 \mathrm{kg} / \mathrm{m}^{3}$ as measured by cubic metre box.

5. Quantity Forecast

While planning a processing or disposal facility as well as the total solid waste management system, forecasting the future load becomes necessary. Increased commercial and industrial activities would result in increased release of wastes and is known to increase per capita waste generation as well. It is reported that an increase of 1-5% per annum occurs in USA. In the absence of information of the past trend, it is necessary to rely on recognised trends as observed in existing conditions.

6. Per Capita Refuse from Selected Cities

NEERI observations indicated that the per capita waste reaching disposal site was about 0.5 kg/capita/day in Bombay and Calcutta. In Hyderabad, which is a large city in the same State, due to its cosmopolitan nature and higher standard of living, the per capita value was 0.33 kg/capita/day.

The per capita contribution ranged from 0.15 to 0.35 kg/day for the different Indian cities.