Environmental Engineering Reference
In-Depth Information
Poultry fat
Blood and
feather meal
Poultry meal
By-products
burden
Total
burden
Main products
burden
Center-of-the-plate
cuts
Total burden = Main products burden + by-products burden
Main products burden = factor
´ Total burden
By-product burden = (1- factor ) ´ Total burden
Where the “ factor ”, a number less than 1, it is a
fractional relationship of underlying physical or
economic relationships.
Figure 4.5 The allocation problem in a life cycle inventory for poultry processing. (Illustration is not
drawn proportionally.)
Table 4.4 Sensitivity analysis for allocation in the case of corn wet-milling.*
Product or co-product
Mass allocation (%)
Economic allocation (%)
Energy allocation (%)
Corn gluten meal
6.7
10.0
8.9
Corn gluten feed
23.8
8.0
12.8
Corn starch
61.0
78.0
67.3
Corn germ meal
8.5
4.0
11.0
* The analysis uses mass, economic value, and gross chemical energy.
Reproduced from Ayer et al., 2007, with permission from Springer.
indicators. A sensitivity analysis is a comparison of allocations performed using different
criteria and the selection of one is based on careful examination and weighing of pros and cons
for each criteria. Table 4.4 contains an example of a sensitivity analysis performed on the LCA
of corn wet-milling. The example contains allocations using mass , economic value , and gross
chemical energy to the main product and co-products of this process. A close examination of
Table 4.4 shows that different criteria generate different allocation coefficients.
Life cycle impact assessment
In the LCIA, the outcomes of the life cycle inventory (LCI) are analyzed in terms of their
potential impact on human health and environmental degradation as well as resource deple-
tion. The LCIA goal is to connect resource extractions from nature and emissions into nature,
which are listed in the LCI, to their potential environmental damages (Jolliet et al., 2004).
 
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