Page 73 - Solid Waste Analysis and Minimization a Systems Approach

LIFE CYCLE ASSESSMENT 51

which impact categories included. A common approach to this has been developed by
the Swedish Environmental Institute and Volvo by creating six environmental indices.
These indices are

1 Scope—The general impression of the environmental impact
2 Distribution—The extent of the affected area
3 Frequency or intensity—The regularity and intensity of the problem in the affected
area
4 Durability—The permanence of the effect
5 Contribution—The significance of 1 kg of the emission of the substance in relation
to the total effect
6 Remediability—The relative cost to reduce the emission by 1 kg

2.7.3 LIFE CYCLE INVENTORY

The second phase of LCA involves performing an inventory analysis. Usually the
starting point is to develop a process flowchart that sequentially describes the entire
process from cradle to grave and includes

■ The process step
■ Inputs into the process (raw materials, chemicals, and energy)
■ Outputs and emissions from the process (air emissions, waster emissions, and solid
waste)

The data must be related to the functional unit defined in the goal and scope defini-
tion. Data may be presented in tables and some preliminary interpretations may be
completed at this stage. The result of the life cycle inventory is a list which provides
information about all inputs and outputs in the form of elementary flow to and from
the environment from all the unit processes involved in the study.

2.7.4 IMPACT AUDITS

The third phase LCA is aimed at evaluating the contribution to the impact categories
specified in the scope and goal. In this phase, impact potentials are calculated based
on the results from the inventory phase and are normalized and weighed based on the
functional unit. Normalization provides a basis for comparing different types of envi-
ronmental impact categories (all impacts get the same unit). Weighing implies assign-
ing a weighing factor to each impact category depending on the relative importance.

2.7.5 ANALYSIS AND ACTION
The fourth phase of LCA focuses on using the results of the inventory and audit por-
tions to make decisions. An analysis of the major contributions, a sensitivity analysis
and an uncertainty analysis are used to draw the conclusion and recommendations to
meet the goals of the project.