Page 111 - Materials Chemistry, Second Edition

Life Cycle Assessment: Principles, Practice and Prospects
98

2.50
Infrastructure
Greywater treatment
Urine disposal
2.00 Water trucked in
Wastewater treatment
Wastewater pumping
kt CO 2 eq. 1.50 Water supply

1.00

0.50

-
0 1.1 1.2' 2.1A 2.1B 2.2A 2.2B 2.2C 2.2D 2.3 2.4 3
Figure 8.3 Infrastructure greenhouse impacts versus operational impacts for a series of supply
and disposal options (Grant and Opray 2007).

8.3.1 Infrastructure
Infrastructure in water systems usually comprises tanks, pumps, pipes, foundations, excava-
tion, catchment devices, settling ponds and other similar components. To determine the
impact of such elements, detailed design information is required about these components and
how the system will function. Understanding the detailed design of the water system to be
analysed often takes as much effort as undertaking the LCA itself because most water system
designs are not simple, especially when a large system boundary is drawn.
Two contrasting examples of water supply system designs are shown in Figure 8.4. They
illustrate a limitation of LCA that is often overlooked. Typically, LCA is used to assess a design

2
(b) House Lot (533 m net) 14 m x 38 m
(a) Scenario 2B House Lot (586 m 2 gross) 15 m x 39 m
Mains water supply Total lots 24 x 30 = 720 DN225 main
Block area = 45.5 ha
DN100 main
1 × 30

Other uses

940 m
WC
2250 L
Float switch for
tank mains backup
for toilet flow
pump
outdoor outdoor
450 m
Figure 8.4 Design variations for water supply systems: (a) simple tank system design (Hallmann et
al. 2003); (b) extract of suburban reticulated network design (Sharma et al. 2005).

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