Newsletter and Technical Publications
<Municipal Solid Waste Management>
Regional Overviews and Information Sources
Latin America and the Caribbean
2.4 Topic e: Landfills
The use of landfills in Latin America and the Caribbean
has increased significantly in the last decade. All capital and other large
cities in South America, Mexico, Costa Rica, and Trinidad and Tobago have
landfills of some sort. Many of these landfills, however, are more like
controlled dumps: someone checks (but does not weigh) trucks entering the site,
and waste pickers do not actually sleep on the site. In many cases, the wastes
are covered daily. However, there is neither a clay nor a synthetic lining,
often no leachate collection system, and no environmental monitoring.
Altogether, approximately 60% of the waste generated in the region is disposed
of in such "landfills."
Some large cities in the region (including Belo Horizonte, Buenos Aires,
Guayaquil, Medellin, Mexico City, Santiago, and Sao Paulo) do have state-of-the
art landfills. Landfill design in these cities typically consists of an initial
clay layer, followed by a sand or ground stone layer. Synthetic liners are not
usually used except for some new landfills in Argentina, Brazil, and Chile.
Leachate collection systems are used, the landfills are subdivided into cells,
and they have chimneys for gas ventilation. Wastes are covered daily with
topsoil. When full, landfills are closed by covering with a clay layer and
topsoil, then revegetated.
To get a more rounded picture, one can look at a World Bank analysis of
landfills in Mexico: a total of 97 controlled final disposal sites were
identified, of which only 11, mostly located in the northern part of the
country, had equipment and instrumentation features that could allow them to be
considered landfills, rather than dumps. Many Mexican landfills face significant
operational and environmental problems, as access and disposal are uncontrolled
and leachates not contained, treated, or monitored. This analysis concluded that
only 15% of the MSW generated in Mexico is disposed of adequately.
In most landfills in the region, leachates go untreated, resulting in their
infiltration into ground or surface water. Some notable exceptions are landfills
in Santiago (where rainfall is very low) and in Brazil, which recirculate the
leachate into the landfill, and one landfill in Buenos Aires, which has
physical/chemical and biological treatment of leachates. Mexico City has also
installed a treatment system in one of its landfills.
Because of the high organic content of the region's wastes, landfilled wastes
tend to produce methane relatively quickly. Nevertheless, this gas is only used
in Chile (Santiago and Valparaiso), where three landfills have gas collection
systems. The gas is used by the cities' gas companies and reaches approximately
30% of the population in each of the cities. In Rio de Janeiro landfill gas was
formerly used as fuel for trucks and in heavy machinery. With falling gas
prices, however, it is now cheaper to use commercial gas.
Central America (except for Costa Rica), the Guyanas, and most Caribbean
countries do not have landfills. This is also the case for all non-capital
cities in Bolivia, Ecuador, and Peru, and for many medium-sized cities with the
exception of those in Chile, Cuba, Trinidad and Tobago, and Colombia. In the
absence of landfills, wastes are disposed of in open-air dumps. These dumps pose
significant environmental health risks, which, in some cases, have been
documented. Waste pickers enter freely into the dumps, sometimes living there.
These people gather a wide range of materials, including food residues to feed
pigs.
Though attempts are constantly made to prevent waste pickers from entering
dumps, these efforts are usually unsuccessful. In one case in Colombia, however,
both waste pickers and former guerrillas were trained and financed to start
recycling and street cleaning enterprises when one dump was upgraded.
Many landfills are operated by private enterprises, particularly in
Argentina, Brazil, Chile, Colombia, and Mexico. Typically, the land is owned by
the local government and is given to the enterprise, which works under a
concession contract.
There is no authorized disposal of MSW at sea. However, some of the poorer
coastal cities do deposit MSW on river banks and by the ocean. The wastes are
then washed into the ocean. There are also several cases where land is being
gained from the ocean by filling with demolition wastes. MSW ends us in these
places, too, causing serious odor problems.
Manual landfills
In cities with less than 50,000 inhabitants, manual landfills are being
developed. Manual landfills are similar in design to mechanized landfills except
for their size and the equipment they require. These landfills have the capacity
to receive 10-50 tons per day of wastes. They sometimes require the use of heavy
equipment, but only for periodic preparation of the terrain. Otherwise, landfill
operation is carried out manually, including cell preparation, compaction, daily
cover, and cell closure. The capital and operation and maintenance costs of
these landfills are lower than a mechanized landfill. The most successful cases
are in Colombia, although Chile, Costa Rica, Honduras, and Peru all have manual
landfills, and Ecuador and Panama are planning to have them. Manual landfills
are often the best option for small cities and towns.
In Peru, a manual landfill in Cajamarca is working well, serving 80,000
inhabitants and processing about 40 tons/day. Those involved in manual landfills
in Colombia believe that in general 20 tons/day is the maximum that such
facilities can reasonably handle.
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