Article - Energy and environmental potential of solid waste in Brazil, Năng lượng và môi trường tiềm năng của chất thải rắn ở Brazil (Vietsub)

3500
F.A.M. Lino, K.A.R. Ismail / Energy Policy 39 (2011) 3496–3502
4%
2%
15%
13%
Campinas - 1996
46%
Organic matter
Paper and cardboard
Plastics
Glass
Metal
Others
Table 2
Recycling and its impacts in Campinas and Brazil.
Discription Campinas Brazil
Useful collected recyclables (t/month) 279.0 101,673
Avoided energy (GJ/month) a 9905 3,609,392
Avoided CO 2 (tCO 2 /month) b 633 230.798
a Assuming that recycling economize 35.5 GJ/t of recyclables.
b Considering an average of 2.27 tCO 2 /t of reused recyclables.
20%
2%
2%
3%
25%
16%
Fig. 1. Solid waste composition in Campinas.
Brazil - 1990
52%
The rejection index for Campinas was calculated using the
primary data of the selective collection provided by the municipality
public power. The index is found to be 21.7% and is adopted
for Brazil. The total residential solid waste collected in Campinas
is 655 t/day. From this total the selective collection represents
0.8%. The household solid waste collected in Brazil is about
125,000 t/day and when applying the above rejection index, the
selective collection becomes 2.7%.
4.3. Recycling: energy and CO 2 emissions
Organic matter
Paper and cardboard
Plastics
Glass
Metal
Others
Fig. 2. Solid waste composition in Brazil.
The substitution of raw material by recycled one in the
production processes leads to energy economy and reduce possible
emissions of gases to the atmosphere. Based upon McDougall
et al. (2001) and Hekkert et al. (2000a, b), the energy economy
due recycling paper and cardboard is 32.9 GJ/t, plastic results in
87 GJ/t, while recycled glass leads to energy economy of 3.5 GJ/t
and recycled ferrous metal results in energy economy of 18.6 GJ/t.
It is important to mention that other recyclables such aluminum,
copper, styrofoam were not included in the present analysis.
The term energy economy refers to difference between energy
consumption in the production process when using raw material
and the energy consumption when using recyclable material. The
calculations include also the inherent energy content of the
material substance. In case of plastics it is the energy content of
petroleum and in case of paper and cardboard it is considered as
wood energy content. Table 2 shows the estimates of energy
economy and the quantity of CO 2 not emitted to the atmosphere
due to recycling in Campinas and Brazil.
In the case of Campinas, the energy consumption for transporting
the recyclables was measured and subtracted from the
energy economized by recycling to determine the potential
effectively economized. The energy consumed in the transport
of the selective collection in Campinas corresponds to about 3% of
the energy economized by recycling (Lino et al., 2010).
Hence the energy effectively economized due to recycling is
about 9607 GJ/month. The energy savings due to recycling in the
city of Campinas represents per month the equivalent electric
energy consumption of 3200 average class residences or 11.700
Table 3
Recycling potential and its impacts.
Description Campinas Brazil
Estimated potential of collected recyclables 8057 1,173,750
(t/month)
Estimated potential of economized energy
286,006 41,668,125
(GJ/month)
Estimated potential of avoided CO 2 (tCO 2 /month) 18,288 230.798
Quantity of CER 4983 62,888
inhabitants considering 3.7 persons/household an average class
residence consumption of about 0.9 GJ/month and a thermal to
electric energy conversion efficiency of 30%.
It is worth mentioning that the data presented in Table 2
corresponds to the energy economized from recycling only 8.6% of
the recyclables potentially collected in Brazil as in Table 3.
In the environmental aspect, the quantity of economized
energy due to recycling in Brazil can avail to the carbon market
a big number of CER as in Table 3. These CERs can be converted to
funds to be used for financing pro ambient projects and for
intensify selective collection and recycling activities.
In order to demonstrate to the Public Administrator the
implicit potential and capacity of recycling as an effective tool
for ambient sustainability and the necessity to create incentives
and adequate public policies, calculations were realized to estimate
the potential of CO 2e avoided due to recycling all the
potentially available recyclables in Brazil, as in Table 3.
If all the potential of generated recyclables is used, this
quantity of energy corresponds to more than half the installed
capacity of the biggest hydroelectric power station in Brazil, that
is, Itaipu. The same quantity of energy corresponds to the electric
energy consumption of 12,963,420 residences or 47,575,740
inhabitants.
To achieve this Brazil has to establish policies which permit
the optimization of energy use, increase the recycling index,
objectives which can only be achieved by the society and the
government combined efforts and by the adoption of highly
objective public policies.
Issues associated with the climate changes are widely discussed
and continuously investigated since 1990 when the first
report of the Intergovernmental Panel for Climatic Changes, IPCC.
In a sequence of four successive reports, the last of which
published in 2007, shows that man aggressive interference in
the ambient contributed and still contributing to the increase of
the planet average temperature, estimated for the next hundred
years to raise from 1.4 to 5.8 1C. Both heating and cooling of the
global climate are related with the concentration of the greenhouse
effects which are the CO 2 ,CH 4 and NO x (IPCC, 2007).
The climate changes are observed all over the planet in the
continents and the oceans together with ambient temperature
changes, ice in Artics, changes in precipitation everywhere,
changes in the ocean salinity, wind patterns, and extreme
ambient aspects such strong precipitation, extreme heat and
coolness and strong tropical cyclones (IPCC, 2007).