Page 239 - Materials Chemistry, Second Edition

226 LIFE CYCLE ASSESSMENT HANDBOOK

9.5 Overview of the Role of Ecosystems in Sustainable
Design

The preceding sections dealt with ecological goods and services in an ana-
lytical fashion by accounting for these vital resources in life cycle analyses.
Ecosystems can and must also be accounted for and included in sustainable
design problems. The only systems that we know have sustained themselves
for millennia are ecological systems. Despite the previously mentioned limits
imposed by the second law of thermodynamics, ecosystems are able to sustain
themselves by building a strongly connected network where all materials are
recycled and the only waste is that of low quality heat. Such networking means
that individual ecological processes do not have to be particularly efficient,
as long as there are other processes that can take advantage of the waste. In
addition, ecological systems are able to rebound to a productive state even
after catastrophic disturbances (Halpern, Frenzen, Means, & Franklin, 1990).
Consequently, it has often been suggested that technological systems should
learn from and emulate ecosystems. This has been the source of ideas and
approaches such as Industrial Ecology (Jelinski, Graedel, Laudise, McCall, &
Patel, 1992), Ecologically Balanced Industrial Complexes (Nemerow, 1995),
Biomimicry (Benyus, 1997), and Ecological Engineering (Mitsch & Jorgensen,
2004). The first two approaches focus on developing networks of industrial
systems where "waste equals food/ 7 often referred to as By-Product Synergy
(Forward & Mangan, 1999). Thus, the waste from one process should be used
as a resource in other processes. Many efforts have focused on developing such
industrial ecosystems (Chertow, 2007). However, a crucial shortcoming of such
approaches is that they ignore the role of ecosystems, and in general, there
is no consideration of ecosystem ecology in industrial ecology (Tilley, 2003).
The approach of biomimicry and ecological engineering has been developed
mainly by ecologists, and aims to engineer ecosystems to provide goods and
services essential for human activities (Mitsch & Jorgensen, 2004). The under-
lying belief being that since ecosystems are self-sustaining, they can be better
for supporting human activities than traditional technological alternatives. For
example, instead of conventional methods for treating wastewater, the ecologi-
cal engineering solution would be to allow a wetland to self-organize for treat-
ing the waste. Similarly, for dealing with degraded soil, ecological engineering
suggests building the soil ecosystem such that it can make soil and enhance
its quality, instead of the traditional approach of trucking in new soil. There is
little doubt about the sustainability of such approaches, but little attention has
been directed toward considering such engineered ecosystems in industrial
design.
The main goal of this section is to introduce the idea of designing techno-
ecological (TE) networks as essential components in sustainable systems. Such
an approach explicitly accounts for the role of ecosystems in human activi-
ties and has the potential to overcome the most significant shortcoming of
existing approaches in sustainable engineering. It merges industrial ecology