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					Table 2.2: Sources and Types of Municipal Solid Waste
Sources              Typical waste generators                Types of solid waste

                                                             Food wastes, paper, cardboard, plastics, textiles,
                                                             glass, metals, ashes, special wastes (bulky items,
Residential          Single and multifamily dwellings
                                                             consumer electronics, batteries, oil, tires) and
                                                             household hazardous wastes

                     Stores, hotels, restaurants, markets,   Paper, cardboard, plastics, wood, food wastes, glass,
                     office buildings                        metals, special wastes, hazardous wastes

                     Schools, government center, hospitals, Paper, cardboard, plastics, wood, food wastes, glass,
                     prisons                                 metals, special wastes, hazardous wastes

                                                             Street sweepings, landscape and tree trimmings,
                     Street cleaning, landscaping, parks,
Municipal services                                           general wastes from parks, beaches, and other
                     beaches, recreational areas
                                                             recreational areas

                     New construction sites, road repairs,
Construction and
                     renovation sites, demolition of         Wood, steel, concrete, dirt

                     Heavy and light manufacturing,
                     refineries, chemical plants, power      Industrial process wastes, scrap materials, off-
                     plants, mineral extraction and          specification products, slay, tailings

                     Crops, orchards, vineyards, dairies,    Spoilt food wastes, agricultural wastes, hazardous
                     feedlots, farms                         wastes (e.g. pesticides).

Source: World Bank/IBRD, 1999. What A Waste: Solid Waste Management in Asia

In the Stakeholders’ Guide: Sustainable Waste Management, the UK Environment
Council (2000) also employed source classification to identify the major sources of
waste as municipal sources, commerce and industry, agricultural sources, demolition
and construction activities, dredged spoils, sewage sludge and mining and quarrying
operations. Classifying wastes by their sources is a useful way of determining the
relative contributions of the different sectors of society to the waste stream and how to
plan for their collection and disposal.

Frequently, the material composition of the waste stream is also used to classify
wastes into such types as organic waste, paper and cardboard, plastic, glass, ceramics,
textiles metal and inert waste (Table 2.3). An example of waste classification based
on material composition was conducted by the Surrey County, UK in 2002/2003. An
analysis of household waste streams in the county identified nine main types of

materials: paper/card, plastic film, dense plastic, textiles, miscellaneous combustibles,
glass, ferrous metal, garden waste and food waste (Surreywaste.info, online).

Table 2.3: Material classification of waste
  Waste type                                                 Examples
Paper            Newspapers, cardboards, office waste paper, magazine/glossy
Plastics         Bottles, expanded polystyrene, film plastic, other rigid plastics
Glass            Clear glass, green glass, amber glass, non-recyclable glass
Metals           Steel cans, aluminum cans, other ferrous, other aluminum
Organics         Yard waste-grass, yard waste-other, wood, textiles, diapers, fines, other organics
Inorganic        Electronics, carpets, drywall, other construction and demolition, other inorganic

Using the physical state of waste substances, the materials in the waste stream can
also be categorised into liquid, solid, gaseous and radioactive wastes. Examples of
these types are shown in Table 2.4.

Table 2.4: Classification of waste based on physical state of waste substances
Waste type              Examples
Liquid waste            Sewage sludge, waste water from bath house and kitchens
Solid waste             Food waste, paper, plastic, metal, debris
Gaseous waste           Factory smoke, vehicle exhaust smoke, fumes from burning waste dumps
Radioactive waste       Radiation, uranium, plutonium, excess energy

Furthermore, the potential health or pollution risk of waste materials is used to
classify wastes into hazardous or non-hazardous waste (Table 2.1). On the one hand,
hazardous waste refers to wastes with properties that make them potentially harmful
to human health or the environment (DELM, 1993; US EPA, 2008). According to the
US EPA (2008), hazardous wastes can be liquids, solids, contained gases, or sludge
commercial products like cleaning fluids or pesticides. Because of their potential
pollution danger, hazardous waste materials require rigorous and cautions means of
disposal (DELM, 1993). In the EPA’s Hazardous Waste Listings (2008) the
categories of hazardous wastes include ignitable waste, corrosive waste, reactive
waste, toxicity characteristic waste, acute hazardous waste and toxic waste. Special
waste is one type of hazardous waste which is usually so dangerous to treat, keep or
dispose of that it requires special disposal arrangements (US.EPA, 2008). Examples
include hard clinical waste such as human parts, contaminated swabs and sharps. On

the other hand, non-hazardous waste does not pose a danger and can be dealt with
easily, examples being inert materials such as uncontaminated earth and excavated
waste such as bricks, sand, gravel and concrete slates (Environment Council, 2000).

Waste can also be classified by whether it is biodegradable or non-biodegradable
waste. Biodegradable waste typically originates from plant or animal sources and can
easily be broken down by bacterial action or by other living organisms and so has a
relatively short lifespan in the environment. This type of waste is commonly found in
municipal solid waste as food waste, yard waste and paper. Other biodegradable waste
materials include human excreta, animal droppings, sewage and slaughterhouse waste
(Lapidos, 2007). In contrast with biodegradable waste, non-biodegradable waste,
which includes most plastics, metals and ceramics, are waste substances that cannot
be broken down by natural processes or living organisms (Lapidos, 2007).

The classification of waste into types, as discussed above, is very important for waste
management planning. Among other things, it provides useful information that
enables municipal authorities to organize waste management operations including the
frequency and means of collection, and appropriate disposal methods. The developed
countries have made great advances in waste data generation and analysis which have
enabled them to improve waste management over the years. In most developing
countries, however, even the most basic data on waste such as the quantities generated
and composition of the waste stream are lacking, making it difficult to organise waste
management effectively (Hardoy et al., 2001).

2.1.3. The concept of waste management
The business of keeping our environment free from the contaminating effects of waste
materials is generally termed waste management. Gbekor (2003:18), for instance, has
referred to waste management as involving “the collection, transport, treatment and
disposal of waste including after care of disposal sites”. Similarly, Gilpin (1996:201)
has defined waste management as “purposeful, systematic control of the generation,
storage, collection, transportation, separation, processing, recycling, recovery and
disposal of solid waste in a sanitary, aesthetically acceptable and economical manner”
while Schubeller et al. (1996:7) focus on municipal solid waste management which
they define as “the collection, transfer, treatment, recycling, resource recovery and


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