Environmental Engineering Reference
In-Depth Information
Nowadays in life cycle analyses the main impact categories are:
•
greenhouse effect;
•
stratospheric ozone deletion;
•
acidification;
•
eutrophication;
•
photochemical oxidant formation;
•
human and environment toxicity;
The environmental impacts quantification is performed in the phase of distinction thanks
to scientific models and correspondence's factors, on an international level (i.e., greenhouse
effect follows global warming potential, that is, the equivalent CO
2
quantity). To synthesize
the analysis and compare it with more productive systems, it is necessary to make the data
normal (i.e., to estimate the pro-capite environmental charge) and to carry out a weighing in
order to get a single index of impact. In the last phase of LCA, that is the interpretation, the
results of inventory analysis are correlated with those ones of impacts analysis, to propose
better measures for a reduction of environmental charges.
Life cycle assessment is used for more aims: processes' improvement, products
innovation under new standards of production, assessment of carbon footprint, progress of
environmental policy strategies.
On a planning and organizing level it is very hard to reach a production improvement,
which consists in choosing the solutions to be applied to productive system and suitable to
maximize the global environmental energetic efficiency.
LCA application does not always guarantee a reduction of energy consumption or
emissions, but it allows people to evaluate a service or a product in a total way, in order to
avoid a wrong interpretation, i.e. an improving intervention that moves a problem from the
analysed area to another one.
3.2. Cost Benefit Analysis CBA
CBA is one of the most popular method for investment assessment, especially when they
refer to support measures on territory; it chooses the best proposal, or, in case the proposal is
only one, it verifies the project costs, that should be lower than the benefits, in order to
improve the general social and economic welfare of the project context [15].
CBA is divided into three phases:
1.
identification of all positive and negative effects of the project
. The negative effects
involve: water consumption, wastes production, etc. The positive effects could be:
employment, water availability for civil agricultural or industrial use, the creation of a
green area or a system for waste water conditioning.
2.
quantification of effects from the previous phase.
The costs and the benefits of a project
are expressed in monetary terms, while the other effects are expressed in their own
measure units (jobs number, decibel of produced noise, etc.).
