Page 173 - Materials Chemistry, Second Edition

154 Life Cycle Assessment of Wastewater Treatment

8.7 SUSTAINABILITY, ENVIRONMENTAL CONCERNS,
RISK ASSESSMENTS, AND RISK MANAGEMENT

Currently, fungal wastewater treatment practices are being studied for further reduc-
tion in the pathogenic effects as well as the eco-toxicity of the effluents. However,
from the sustainability point of view, if one of the main functions of WWTPs is to
minimize the impact on the environment, other factors should be considered and
studied as well as the PhAC removal efficiency of the applied method (Pasqualino et
al., 2009). It is believed that further improvements in the quality of WWTPs’ efflu-
ents impose an inevitable environmental load on the process, and eventually, at some
point, there will be a “break-even” between the environmental benefits to be gained
by the removal of PhACs and the impacts induced by this treatment. This environ-
mental break-even point has been reported for some studied treatment scenarios,
in which the imposed environmental impact of the treatment exceeded its benefits
(Wenzel et al., 2008). Different wastewater treatment systems have different perfor-
mance characteristics and consequently, impose certain loads on the environment.
On the other hand, increasingly sophisticated improvements in treatment methods
result in more environmental load (Wang et al., 2012), which means that the envi-
ronmental profiles are case specific. In addition to seeking further improvements in
water quality, we should look for strategies to reduce the environmental impacts.
Therefore, the environmental performance of the wastewater practice should be
carefully assessed before proposing its implementation in the WWTP to reduce the
resource use, energy consumption, and environmental emissions attributed to the
process. Often, the environmental loads are neglected due to the regulatory push for
acquiring higher water quality. To establish an ecologically sustainable WWTP, a
comprehensive assessment of available options is necessary to meet different stan-
dards from a life cycle perspective (Wang et al., 2012), and the environmental per-
formance of the employed wastewater treatment method can be assessed by life cycle
assessment (LCA) methodology (Coats et al., 2011).

8.7.1 lca facTors
The economic, environmental, and social dimensions of sustainability need to be
addressed in assessing the sustainability of a project or product. A scientifically
based sustainability analysis also involves value judgments, assumptions, scenarios,
and uncertainties. LCA is a method that is applied to compare, contrast, and evalu-
ate environmental impacts of processes by identifying energy and resource use and
various emissions resulting from a particular life cycle (Coats et al., 2011). Generally,
LCA consists of four steps: “goal and scope,” “life cycle inventory (LCI),” “life cycle
impact assessment,” and “interpretation”. LCA also provides valuable informa-
tion to identify the “priority” areas for improvements, where actions would have
the greatest effect on reducing the corresponding environmental burdens (Hossain
et al., 2008; Rebitzer et al., 2004). LCA is typically restricted to environmental
aspects, while sustainable assessment (SA) is a broader concept and covers more
dimensions or aspects than LCA. Therefore, to “broaden” the scope of LCA, the
social and economic dimensions are added to the environmental aspects. The life