Page 338 - Materials Chemistry, Second Edition

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analysis and management), an LCA software (Ecobalance, 1997), was applied to
the potential impact assessment for the inventory analysis and impact assessment,
while CalTOX and the integrated assessment model Ecosense (IER, 1997) were the
tools used for the site-specific assessment.

8.2 EXAMPLE 1: LANDFILLING OF MIXED
HOUSEHOLD SOLID WASTE (MHSW)

8.2.1 INTRODUCTION
Landfilling of mixed household solid waste (MHSW) was chosen as the first example
for its similarity to the case study “Waste Incineration.” The first applications example
stems from the same life-cycle stage as the case study of the previous chapters:
“Recycle — Waste Management.” A further description of the typical features of that
stage for a life-cycle assessment study can be found in Ciambrone (1997).
Landfill traditionally has been the most widely used method of waste treatment.
However, the practice of landfilling has shown that the disposal of wastes that have
not been pretreated causes emissions corresponding to those of a bioreactor. These
emissions are considered high risk whereas landfills are ranked as the worst option
in the waste hierarchy according to the pollution-preventing principle described in
Chapter 1. In modern landfills the emissions are collected and treated as much as
possible by biogas combustion and leaching effluents purifications.
In this example, an LCA is performed for an average Spanish landfill; then, a
risk assessment is carried out for the substance that has the highest potential danger
according to the human toxicity indicator used in the life-cycle impact assessment
(LCIA). A fictitious site has been designated for this example which can be under-
stood as a fully developed exercise for the sequence life-cycle assessment, dominance
analysis for human toxicity potential and environmental risk assessment.

8.2.2 LCA FOR LANDFILLING OF MIXED HOUSEHOLD SOLID WASTE

8.2.2.1 Introduction
A case study of an LCA concerning the treatment of 50,000 t of mixed household
solid waste (MHSW) in a medium-size Spanish landfill is performed. The data of
the inventory include the consumption of raw materials and energy through the use
of containers, collection and transport of wastes and the management of the landfill,
and the corresponding emissions to air, water and soil. The following nine envi-
ronmental impact categories have been considered in the impact assessment phase
of the LCA: water eutrophication; depletion of nonrenewable resources; air acidi-
fication; greenhouse effect; aquatic eco-toxicity; human toxicity; terrestrial eco-
toxicity; depletion of the ozone layer; and photochemical oxidant formation. The
®1
software model and database WISARD (waste integrated systems assessment for
recovery and disposal) of Ecobalance Price Waterhouse & Coopers, mentioned in
Chapter 2, has been used in the inventory analysis and impact assessment phases
of the LCA (Figure 8.1).

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