Challenge Garbage Burning
By Mario Osava*
"Usina Verde" project aims to help curb climate change through a
different approach to waste management, but it could be a source
of other contaminants.
RIO DE JANEIRO - The "Usina Verde" project
seeks to generate energy in Brazil while eliminating urban waste
and helping to reduce global warming. But its good intentions have
not won over environmental groups because the plan involves burning
The pilot plant of the project, which involves capital from a private
company of the same name, began operations in May 2005 in Rio de
Janeiro and is already converting 30 tons of garbage a day into
2.6 megawatts of energy.
The sponsors of Usina Verde hope to sell facilities like the Rio
de Janeiro plant to municipalities throughout the country.
The plan "cannot be considered clean or sustainable," Temístocles
Marcelos, head of the Brazilian Forum of Non-Governmental Organizations
and Social Movements for the Environment (FBOMS), told Tierramérica.
The incinerators are sources of persistent organic pollutants, known
as POPs, like dioxins, furans and heavy metals, condemned by the
2001 Stockholm Convention because they harm human health over the
course of several generations, he said.
Dioxins are carcinogenic, affect the endocrinological system and
are transmited through the food chain, including through mothers'
milk. The POPs present in the gases, ash and other residues from
incineration are dangerous, even in proportions lower than those
allowed by national regulations, Marcelos said.
Among the benefits of Usina Verde, nevertheless, are the elimination
of big dump sites and landfills that pollute the air and groundwater;
and the potential for generating carbon credits through the Clean
Development Mechanism of the 1997 Kyoto Protocol, which allows industrialized
countries to invest in greenhouse gas reduction projects in developing
The project, one of 72 already approved by the Brazilian Inter-Ministerial
Committee on Global Climate Change, now has to go through the United
Nations before it can become part of the carbon market system.
Designed by the Climate Center at the Federal University of Rio
de Janeiro (UFRJ), the project is based on technology developed
by the Usina Verde company in association with several universities.
The carbon credits would arise from the reduction in emissions of
gases that contribute to global warming, that is, the methane normally
produced by garbage dumps and the carbon dioxide from electrical
energy production fuelled by petroleum or coal. Emissions would
also be reduced because the garbage trucks would no longer have
to travel to distant landfills.
A pilot plant on the UFRJ campus processes 30 tons of garbage daily,
producing electricity through its "controlled burn" process. Recyclable
and non-combustible materials are separated from the waste that
the plant receives from an urban sanitation company.
The gases and vapors produced by combustion at temperatures of 850
to 1,000 degrees are cooled and then cleaned to prevent contamination,
a process that results in mineral salts and water ready to be reused.
The ashes and non-flammable remnants are equivalent to eight percent
of the input waste and, along with the salts, are ultimately used
in producing flooring and bricks. In the future, if it is proved
that they are not toxic, they will also be used in agriculture,
to correct acidic soils, said Emilio La Rovere, coordinator of the
The Usina Verde company has modular installations for sale that
process 150 tons of garbage per day, for 2.6 megawatts of energy
-- enough electricity to supply 7,600 homes with an average consumption
of 200 kw/hour each month.
This type of system is used in 35 countries, especially in Europe,
with 14 million tons of garbage incinerated annually in Germany
and Spain and 26 million in the United States, said La Rovere.
It is a valid alternative in Brazil, where most of the urban waste
accumulates in open-air dumps or "unsanitary" landfills, causing
serious environmental harm and fuelling conflicts amongst municipalities
in the metropolitan areas about the "exportation" of garbage and
the scarcity of land for depositing it, he said.
The project is also economically viable in comparison to the costs
of landfills. The electricity produced is not as cheap as that from
hydroelectric dams, but is compensated with the carbon credits and
factors like the proximity of the energy source and the jobs generated
in the city itself.
But, according to activist Marcelos, the approval of the project
in the context of the Kyoto Protocol could encourage some companies
"to muliply these Usina Verde plants" for commercial interests,
seeking "green publicity", to the detriment of other better options
for treating and making best use of urban solid waste.
Recycling generates more jobs and stimulates the organization of
waste collection cooperatives, in a movement of social inclusion
that now could be blocked by the "incineration of its raw materials,"
However, La Rovere argues that Usina Verde could also adopt foreign
technologies that further reduce emissions of dioxins and furans.
Brazil is burning a great deal of garbage without regulations anyway,
and its thermoelectric use is proposed only as an alternative for
the appropriate management of "perhaps five to 10 percent" of urban
waste, he said.
* Mario Osava is an IPS correspondent.