Newsletter and Technical Publications
<Municipal Solid Waste Management>
Collection and transfer
1.3.5 Technical, regional, and development issues and criteria
In collection, as in any of the other topic areas, it
is critical that both the "hard" aspects of the system (set-out
containers, vehicles, and transfer points) and the "soft issues"
(scheduling, fee systems, and legal framework) be geographically and
socio-economically appropriate to the setting. This is perhaps the single most
important factor in achieving sound practice in solid waste collection. It is
fair to say that no collection system designed without taking these factors into
account can be expected to arrive at sound practice, or even to function
acceptably. Some examples of points to consider are given below.
Geography, settlement pattern, and cultural preferences
Collection and transfer vehicles must take into account terrain, climate, and
settlement pattern. For example, the use of open trucks or carts is often
appropriate in dry climates, but there should be both dust control and the
option to cover loads in the rainy season or when it is windy. If such vehicles
are piled high with waste, the waste will fall off, thus greatly reducing the
efficacy of the collection system.
In selecting a vehicle, an important consideration is the density of housing
stock and the split between single- and multi-family dwellings, which affect how
often the vehicle will have to stop. Street layout, grades, traffic, and road
surfaces affect how easy it is to maneuver.
Compactor trucks work poorly in extremely wet climates, where wastes are
often wet and dense. Compactor trucks in this situation tend to squeeze out the
moisture and discharge leachate onto the street. Also, in coal- burning areas
wastes are high in ash, which cannot be compacted much further. The
industrialized country models of compactor collection with several crew members
may be the appropriate goal in industrialized or rapidly modernizing cities with
formal streets that are wide enough for such trucks. In some cases, compactor
trucks are feasible when paired with a small satellite collection vehicle, such
as a propane- or muscle-driven cart, that collects waste from congested areas
and brings it to the truck.
Cultural attitudes towards waste can govern frequency of set-out or choice of
set-out container system. Vehicle traditions and the availability of drivers
affect the choice of vehicle. Cultural considerations also include whether it is
acceptable for people to see the waste in the vehicle or whether it should be
immediately hidden from view; whether it is offensive to hear an announcement of
the truck's arrival; the issue of who can handle waste and under what
circumstances, and what point of set-out is acceptable. It is worth noting that
cultural attitudes are sometimes altered through education, to some extent.
Waste composition and characterization
A frequent error in the set-up of collection and transfer systems is to
assume that all waste streams are alike. The composition of the waste stream
varies not only seasonally, but within ethnic and social divisions in the same
country. Between countries, hemispheres, and continents, there is rather large
In low-income countries, waste is usually very high in organics, because
other constituents are removed either before set-out or between set-out and
collection. High-income countries, by contrast, tend to have a lower proportion
of organic waste but more paper, plastic, metal, and glass.
Where there is variation on many of these points within a single
jurisdiction, cities, particularly those in developing countries, may need to
have several collection systems, geared to the varying infrastructure and
socioeconomic status of the different service areas. Hybrid systems combining
muscle and mechanical power are frequently appropriate. Sometimes the best
approach is to adapt a system or combination of systems and to tailor them to
the needs of the community. Community leaders should be consulted on the design
of the systems under their jurisdiction.