Environmental Engineering Reference
In-Depth Information
to support the energy use of a remediation process. The secondary footprint is a mea-
sure of the indirect CO 2 emissions from the whole lifecycle of products used within
the remediation - those associated with their manufacture and their eventual break-
down. Note the carbon footprint is not measured in terms of area. The world's first
standard approach was recently published in the UK (Carbon Trust et al. 2008a , b ).
Carbon footprint assessments have been used to describe remediation projects,
for example the proprietary tool: Remediation Options Carbon Calculator. 23 A car-
bon footprint appraisal is a “quantitative” measure of a system's possible impact
on global warming. It may have some importance as part of a corporate carbon
reporting requirement, but it is not a substitute for sustainability appraisal. It can
inform about one indicator within one element (the environmental element) of a
sustainability appraisal.
20.3.4.4 Carbon Balance (Flows)
Carbon balance diagrams illustrate calculations of tonnes of carbon in various
inputs and outputs to an environmental management process, and how this bal-
ance changes for different scenarios (Department for Environment Food and Rural
Affairs 2006b ). For waste management (and so probably also remediation) the major
flows of carbon/greenhouse gases and energy result from: the use of fuel and energy
in processing; the transportation of materials to and from sites; direct releases from
materials on processing (e.g. biological processing or thermal treatment) or disposal
in landfill; avoidance of greenhouse gas emissions or energy use elsewhere in the
economy; and sequestration of carbon in landfill and soil. Carbon balance diagrams
show the fate of carbon for each material and scenario in detail, considering: the
carbon that remains within the material fraction following treatment and re-use or
disposal; carbon that is sequestered in landfill or some other soil carbon sink; carbon
that is contained in products re-used off site; and carbon that is released to atmo-
sphere, as carbon dioxide (fossil/biogenically derived) or methane. The diagrams
also include greenhouse gas balance calculations shown in tonnes of equivalent
carbon dioxide. A carbon balance is a detailed quantitative assessment which not
only compares options, but also identifies opportunities where improvements may
be made. However, as for a carbon footprint appraisal, it relates to only one factor
within an overall sustainability appraisal.
20.3.4.5 Cost Benefit Analysis
Cost benefit analysis is a form of economic analysis in which costs and benefits are
converted into monetary values for comparison (known as “private costs”). Cost
benefit analysis considers a diverse range of impacts (known as “public costs”)
that may differ from one proposed solution to another, such as the effect on human
23 http://atkinsrocc.com/Public/Default.aspx
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