Sustainability and Remediation - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 922

they can be manipulated arithmetically. However, rankings also have limitations;
in particular, they do not consider the “scale” of differences that might separate
particular options: i.e. they only say Option A is better than Option B, but not that
Option A is “much” better or only “slightly” better than Option B.
Rankings can also be used instead of weightings, for example, labelling indica-
tors as “high”, “medium” or “low” importance. A simple sensitivity analysis can
then be used to see the effect of removing indicators of “low” importance from a
sustainability appraisal.
Scaled rankings can be used to determine weights. Rather than saying “Option A
is better than Option B”, scaled ranking say “Option A is 3x better than Option B.”
By limiting the scale to 3x, 5x, 7x and 9x stakeholders are given some but not too
much scope to express the strength of their preference (Nathanail 2009 ).

20.3.4.2 Best Available Technique (BAT)

The concept of Best Available Technique (BAT) was described on the IPPC
Directive (Directive 96/61/EC). 21 The definition of BAT is “the most effective and
advanced stage in the development of activities and their methods of operation
which indicates the practical suitability of particular techniques for providing in
principle the basis for emission limit values designed to prevent and, where that is
not practicable, generally to reduce emissions and the impact on the environment
as a whole”. Where there is a choice, the technique that is best overall will be
BAT, unless it is not an “available technique”. There are two key aspects to the
availability test:

• what is the balance of costs and advantages?; This means that a technique may

be rejected as BAT if its costs would far outweigh its environmental benefits; and

• can the operator obtain the technique (Department for Environment Food and

Rural Affairs 2007b ).

BAT determinations are therefore a partial sustainability appraisal and a limited
form of cost benefit analysis. BAT considers some aspects of sustainability, but his-
torically these were not formally linked to indicators derived from the three elements
of sustainable development.

20.3.4.3 Carbon Footprint (“Area”)
A carbon footprint 22 is a measure of the impact human activities have on the envi-
ronment in terms of the amount of greenhouse gases produced, measured in units
of carbon dioxide. A carbon footprint is made up of the sum of two parts, the
direct/primary footprint and the indirect/secondary footprint. The primary footprint
is a measure of direct emissions of CO 2 from the burning of fossil fuels for example

21 http://ec.europa.eu/environment/ippc /
22 http://www.carbonfootprint.com/carbon_footprint.html