Newsletter and Technical Publications
<Municipal Solid Waste Management>
Regional Overviews and Information Sources
Latin America and the Caribbean
2.4 Topic b: Collection and transfer
A number of large cities in Latin America and the
Caribbean have fairly good waste collection coverage. Buenos Aires, Santiago,
and Havana claim to collect essentially all of their wastes. São Paulo, Rio de
Janeiro, Bogot*, Medellú‹, Caracas, Montevideo, La Paz, and Port of Spain claim
more than 90% coverage. It is not clear, however, whether these figures really
include collection from squatter settlements. The waste collection system of all
other cities in the region is still deficient.
All large cities use conventional equipment for collection and transfer of
all or part of their wastes. Side- or back-loaded compactor trucks carry out the
collection process through pre-established collection routes. Compactor trucks
function well in paved urban areas. However, there is a common problem
throughout the region with respect to the efficient use of this equipment: both
the equipment and maintenance are very expensive. Frequently, municipalities
indebt themselves by purchasing these trucks without taking into account the
infrastructure needed for their maintenance. Thus, a large portion of these
trucks do not operate due to lack of parts or trained personnel.
In many large cities this problem has been resolved by privatizing the
collection services. Waste collection is carried out by private enterprises that
work under concession contracts with the local government. Administration of
funds is more efficient, so the trucks operate most of the time.
Waste collection is also carried out using other means, depending on the
availability of economic resources, road conditions, and socio-economic level of
the collection area. Wastes are collected in regular trucks, front loaded
tricycles, or carts (pulled by a tractor, animal, or person).
Regular trucks are used when compactor trucks are not working or funds do not
allow for the purchase of compactor trucks. Many solid waste professionals
recommend regular trucks over compactor trucks, because costs are much lower,
maintenance is cheaper, and the wastes tend to be very dense, with little
compactability. Still, local government officials are interested in purchasing
compactor trucks, even if this implies large debts, due to the 'modern' image
that this equipment brings.
Semi-motorized and manual collection systems are common in harder-to-reach
areas of the cities, as well as in smaller towns. This waste collection system
is done either by individuals who receive direct payment for their services, or,
by waste collection cooperatives or small-scale enterprises. These small-scale
waste collection enterprises are emerging in large numbers (mainly in the Andean
and Central American regions) to fill a gap left by formal systems. They are
privately run and work either as a concession or are contracted directly by the
local community (through a neighborhood association).
In some squatter settlements in urban areas, there are small-scale
enterprises that engage in pre-collection: collecting wastes and taking them to
a central collection point where the municipality or solid waste authority picks
them up and takes them to the disposal site. In cases where such settlements are
further from urban areas, residents have in some cases established manual
landfills, which are described in the "Landfills" section, below.
Small-scale enterprises dealing with waste collection in the region typically
include from seven to 20 people, although Recuperar, in Colombia, has more than
700 members (although they are not formally employees).
A major problem still unresolved in many cities in the region is the
frequency and efficiency of waste collection. Frequency varies all the way from
daily to once a week (not including the many areas of cities which are not
serviced at all). Frequency, in many cases, is not determined by technical
considerations such as putrefaction rates of the wastes, weather, vehicle
availability, and routing necessities, but rather by how affluent an area is.
Both collection of market wastes and street sweeping in commercial areas are
most often the responsibility of the solid waste authority. In residential areas
each residence is typically responsible for cleaning their part of the curb. In
the case of street sweeping, small-scale enterprises have had a very important
role in the region. These small-scale enterprises tend to be the first (as
compared to collection and disposal enterprises) to become self-sustaining.
Throughout South America, Mexico, and Costa Rica, transfer stations have been
installed or are in the process of being installed. The transfer stations are
usually owned and operated by the agency responsible for solid waste management
in the city.
Transfer stations do not vary widely in design from those found in the
technical manuals. Compactor or regular trucks arrive at the station, where they
dump the wastes into large, specially designed trailers which deliver the wastes
to the disposal sites. These trailers usually do not have compactors. In Bogot*,
however, there is a transfer station that uses stationary compactors, and in Rio
de Janeiro, wastes are deposited into a funnel system that compacts the wastes
into a trailer.
The need for the transfer stations has grown significantly in the past 10
years as the distance between the city and the disposal sites grows. In cities
such as Rio de Janeiro, Mexico City, Caracas, and Buenos Aires, more than 50% of
the wastes go through a transfer station.
Transfer stations have proven to be much more cost-effective than trucks
going to the landfill. Fuel costs are substantially reduced. Mileage demand on
trucks is lower so that operation and maintenance costs are lower and truck
lifetimes are longer.