Generation of solid waste is a result of natural, human and animal activities. Knowledge of generation of solid waste is important in the planning, designing and operation of solid waste management system. Generation of solid waste has two aspects: One is the quality of solid waste and the other is the quantity of solid waste. Quality includes the sources, types and typical composition of solid waste along with its properties whereas the quantity represents the generation rates and total quantities and volumes of waste generated.
Quantity of the Solid Waste
Determination of the generation rate of solid waste is the most important parameter required in the design of management and subsystems. Solid waste is usually quantified in terms of generation rate i.e. amount of waste generated by a person or a facility in one day. The estimated generation rate for municipal solid waste of Peshawar as reported is 0.65 kg/capita/day.
Quality of Solid Waste
The quality of solid waste not only encompasses different types and sources of solid waste but also include its physical chemical and biological characteristics.
Measures of Quantities
- Volume measurement.
- Weight measurement.
Care is required in using volume measurement because of the distinction between compacted and loosened waste. Both have different weight and volume. Weight of the solid wastes is the most accurate and preferred basis for records regardless of whether the waste is loose or compacted.
Units of Measurement
- Residential and Commercial – kilogram per capita per day (Kg/c/d).
- Agricultural – Kilogram per hectare per year (kg/ ha/ year).
Methods Used to Determine Generation Rate
Load count analysis:
Counting the number of loads over a specified period of time. Knowing the weight of each load, the maximum and average generation rates can be determined.
Measuring the volume of the truck and knowing the average density of waste, the generation rates can be determined.
Material Balance approach:
Indirect calculation of generated waste, by drawing correlations between activities and waste generation. For example, a commercial activity worth X Million Rupees will generate Y kgs of waste. If we have the data, then such correlations can be established for all areas. Expensive and inaccurate in the beginning, but saves a lot in the long run.
Factors Affecting Generation Rates
Factors that affect the generation rate of solid waste include:
- Geographical location – related primarily to the different climate and also the culture that can influence both the amount generated and collection operation.
- Season of the year.
- Frequency of collection of solid waste.
- Characteristics of population: e.g. Income and education levels, also profession classes.
- Extent of salvage and recycling of wastes.
- Legislation regarding solid waste generation, collection and its disposal.
- Public attitude towards solid waste.