Page 54 - Materials Chemistry, Second Edition

Life Cycle Assessment of Municipal Wastewater and Sewage Sludge Treatment 35

Life cycle assessment
framework

Goal and Product
scope development
definition
Marketing Product
improvement
Interpretation
Inventory Application
analysis Public Strategic
policy
making planning
Impact Others
assessment

FIGURE 3.1 Framework and applications of LCA methodology. (Adapted from ISO 14040.
Environmental Management and Life Cycle Assessment—Principles and Framework.
International Organization for Standardization, 2006a.)

selection of the FU is of major importance, because different FUs could lead to dif-
ferent results for the same product systems (Panesar et al., 2017).
The presentation of the product/process to be assessed will provide the frame-
work for the system boundaries as well as the limitations of the study. Accordingly,
the specificities for each case study must be clearly stated from the very beginning.
Regarding the selection of the system boundaries, physical, geographical, and tem-
poral approaches will determine the stages of the life cycle to be assessed (research
and development, material extraction, component manufacturing, use, and manage-
ment and disposal at the end of life).
In the specific case of wastewater treatment, the system boundaries will typically
include primary and secondary treatment (tertiary processes can also be present in
some facilities) as well as the production of energy and chemicals and the emissions
associated with the process (Figure 3.2). When evaluating lab-scale technologies,
scale-up has great importance, especially with regard to infrastructure, operational
yields, and energy consumption. Over- or underestimation of these items can totally

Chemicals Wastes

Primary Secondary Tertiary Sludge
treatment treatment treatment

Energy Emissions

FIGURE 3.2 The framework of wastewater treatment.