Page 90 - Materials Chemistry, Second Edition

L1644_C02.fm Page 66 Tuesday, October 21, 2003 3:07 PM

Therefore, the results of the MSWI LCA were compared with data on the Spanish
electricity mix. This comparison depends strongly on CO emissions. If the neutrality
2
of CO from renewable resources is considered, the life-cycle inventory results of
2
the Spanish electricity mix will not change remarkably, but in a life-cycle study of
municipal waste incineration, the high content of renewable materials that are burned
will provoke different results. Thus, adapting the LCA methodology (Sonnemann
et al. 1999), the total amount of CO in the incineration process needed to be
2
distributed in two parts between the carbon containing wastes: one for waste orig-
inating in renewable resources and the other for waste with its origin in fossil fuels.
Therefore, it is considered that the waste contains 13% plastics, as the only compo-
nent with its origin in fossil fuels, and that the carbon content of plastics is 56.43%,
according to U.S. EPA (1996b).
The quantitative comparison was made with the software TEAM. The database
integrated in TEAM was used for the emissions of Spanish electricity production.
The calculation was normalized to 1.016 MJ electricity, which corresponds to the
incineration of 1 ton of municipal solid waste as functional unit. The absolute values
in Table 2.7 show the results for selected priority air pollutants. Positive values
represent higher emissions of the average electricity production in Spain than in the
SIRUSA plant. This means that emissions of CO, heavy metals, Ni and SO are
2
much higher in the conventional electrical power plants. The negative values present
pollutants that are lower for the average Spanish electricity mix than in the MSWI
incineration process chain of Tarragona.
Table 2.8 compares the results of Scenario 2 with the data of the Spanish
Electricity mix given by Frischknecht et al. (1996) for selected priority air pollutants.
Positive values in Table 2.8 represent higher emissions of the average electricity
production in Spain than in the SIRUSA plant. This means that emissions of CO,
heavy metals, Ni, particles and SO are much higher in the conventional electrical
2
power plants The negative values present pollutants that are lower for the average
Spanish electricity mix than in the MSWI incineration process chain of Tarragona.

2.8 QUESTIONS AND EXERCISES

1. What are the main advantages of LCA?
2. What are the main steps of LCA and in which ISO regulation are they
considered?
3. In which steps of LCA are each of the following different functions carried
out: a) allocation; b) selection and definition of impact categories; c)
identification of the most important results of the IA?
4. What information should be given at the end of the interpretation phase
of an LCA?
5. Design the LCA framework scheme for the case of an old fabric factory
building with a main structure made of steel and reinforced concrete,
which has been in use for 50 years and has subsequently been transformed
into a department store. Consider that the department store has been
operating for 20 years and that the building is finally knocked down. The
owner of the department store invested an additional amount, taking some

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