Environmental Engineering Reference
In-Depth Information
value added in the economic system, a product and employment for the social system, and
undesirable outputs in the ecological system (Tyteca, 1998). Sikdar (2003a) classifies the
Earth systems according to where decisions are performed in four levels or types:
Type I: Planet level.
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Type II: Community level.
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Type III: Business level.
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Type IV: Sustainable technology level.
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A Type I system is one for which all solutions should be achieved by political negotiation at a
global scale. Examples of this type of problems are ozone depletion, global warming, and energy
availability. The Kyoto protocol on climate change is an example on the attempt to address prob-
lems of global consequences. In a Type II system, decisions are made at a local level. Examples
are a city urban development, a watershed, and a public transportation system. A Type III system
encompasses businesses that are “motivated by both good business practices and government
regulations” (Sikdar, 2003a). A Type IV system includes decisions about sustainable technologies
such as green processing practices, use of renewable raw materials, and renewable energy.
Sustainability metrics for the food industry fall into the Type III (business) and Type IV
(processes). The purpose of sustainability metrics is their use as decision-making tools to
compare different alternatives such as technology or raw materials, improvement options,
suppliers, purchasing of raw materials, environmental performance of new products, and as a
communication tool to stakeholders (Tanzil et al., 2004).
Indicators applied to the food industry
There are no specific environmental indicators for the food industry at the current time; how-
ever, indicators that have been developed for other applications or industries are appropriate
for the food industry. It is important to mention that these are not the only metrics available.
For the purpose of this discussion, the environmental performance indicators, or metrics, are
classified into the following categories:
1. Ecological indicators.
2. Process indicators.
3. Transportation indicators.
4. Institutional indicators.
Ecological indicators
The ecological footprint is an indicator used often on a global scale to account for the impact
of population on the planet. However, this indicator is well-suited to describe smaller systems
such as companies, processes, or products. The ecological footprint is a measure of how much
land and water area is required to produce the resources a system consumes and to absorb its
wastes (www.footprintnetwork.org).
The Sustainability Process Index (SPI) is a tool with the same roots as the ecological footprint,
but it has been designed with the language of engineers in mind. SPI has multiple uses such as
optimization of technologies, products, and processes; comparison of alternatives, and identifica-
tion of steps with highest environmental burden (Narodoslawsky and Niederl, 2006). The SPI is
based on the notion that a sustainable process is built on solar flow (an unlimited resource from any
practical viewpoint) that is captured by Earth's land, which is considered a limited resource.
