CHAPTER 4 IMPACT ASSESSMENT
Introduction
Life cycle impact assessment LCIA is the third phase of LCA. The main goal of this stage is to interprete the quantified environmental burden in LCI stage.
Impact selection, category indicators, and LCIA model used in this research reflect the environmental issues of the observed system. Classifications involve
aggregation of environmental burdens to a small number of environmental impact categories which will demonstrate their impacts on existed resource depletion. In
this stage, the existed environmental burden is calculated and analyzed as well as interpreted as the potential impacts. The purpose is to present the potential
impacts in the form of analysis which is useful as the research outputs and can be understood by users.
LCA model focuses on physical characteristics of industrial activities and other economic processes; it does not include market mechanisms or secondary
effects on technology development. In general, LCA regards all processes as linear, both in the economy and in the environment. LCA is a supporting tool
based on linear modeling. Furthermore, LCA focuses on environmental aspects of products and disregard the economic, social, and other characteristics. The
environmental impacts are often defined as “potential impacts”, as they are not specified in time and space and are related to an arbitrarily defined functional unit.
Although LCA aims to be science-based, it involves a number of technical assumption and value choices. An important role is played by ISO standardization
process, which helps to avoid the arbitrariness. Another important aim is to make these assumptions and choices as transparent as possible. Finally, fundamental
characteristic considers that LCA is an analytical tool as it provides information for decision support. However, LCA can not replace the decision making process
it self.
The objective of this chapter is to carry out impact assessment on data collected in Chapter 3 and assess some option scenario to obtain optimum result
which reflects the real condition of Indonesia.
Literature Review
In the impact assessment phase, the result of inventory analysis is interpreted on the contribution to a relevant impact category such as the depletion
of abiotic natural resource, climate change, acidification, and many more. There are three different groups of impact category that can be chosen based on the
interest of environment in relation to LCA and available characterization method. Intervension conducted on inventory analysis results is quantified in general
indicator. In impact category, a characterization method consists of category indicators, model characterization, and factor characterization. According to
Ciambrone 1997, Life Cycle Assessment considers 5 output types, i.e.: atmospheric emissions, water borne wastes, solid wastes, products, and by-
products. These are some points of basic characterization methods developed by
Guinee et al. 2001 which is used on baseline impact categories. The first group, basic impact category, consists of 11 impacts, i.e.:
- Resource depletion
- Land use impact land competition
- Climate change
- Stratospheric ozone depletion
- Human toxicity
- Ecotoxicity, consists of 3 impacts: fresh water aquatic ecotoxicity, marine
aquatic ecotoxicity, and terrestrial ecotoxicity.
- Photo-oxidant creation
- Acidification, and eutrophication
On the second group, study specific impact categories consist of 9 impacts: - Impacts of land use losses on life support functions, losses on flora and fauna
diversity - Ecotoxicity, consists of two types: toxicity impacts on sediment in fresh water
and marine ecosystem - Impacts of ion radiation
- Noise, heat energy waste - Causal relationship
On the third group, another group category consists of three impacts which can be added when needed:
- Abiotic resource depletion - Dry preservation
- Maladourous water
In the classification stage, the results of inventory analysis are classified into appropriate impact categories. In the characterization stage, the results are
calculated to be combined with appropriate characterization factors, and the calculations are processed to obtain indicator scores. A complete collection of
category results produces an environment profile. The primary goal is to obtain a better under standing about relative interests and the amount of interests on each
product system used in the study. The last two stages in this phase i.e. grouping and weighting are considered as optional stages. Grouping assigns impact
categories into one or more sets to provide better facilitation on the interpretation of the results into specific areas of concern. Weighting determines numerical
factors of each evaluated impact category according to relative interests.
Key steps of a Life Cycle Impact Assessment
Steps of LCIA conducted in the research are: 1 Selection and definition of impact categories: identifying relevant
environmental impact categories. Five points related to the research are: global warming potential, acidification, eutrophication, waste landfill volume, and
energy consumption.
2 Classification: classifying data inputs and outputs of inventory analysis into impact categories e.g: classifying CO
2
emission to global warming potential. 3 Characterization: modeling environmental impact within impact categories
using science-based conversion factors e.g., modeling the potential impact of CO
2
and methane CH
4
on global warming
4 Normalization: comparing impact indicator emission factor data based results with standardized value. Due to the absence of normalization standard in
Indonesia, MiLCA-JEMAI software refers to IPCC data and other common standards according to LCA-ISO 14040.
5 Grouping: sorting or ranking the impact indicators e.g: sorting the indicators by location: local, regional, and global.
6 Weighting: emphasizing the most potential impacts. The first three steps are mandatory to build an LCIA model while the other
steps are optional. Impact category selection, category indicators, and LCIA model must be consistent with the goal and scope of LCA and must reflect
environmental issues of the observed system. Classifications involve aggregation of environmental burden to a small number of environmental impact categories
which will demonstrate their impacts on human health, ecological health, and resource depletion rate. In this step, existed environmental burdens are calculated
and analyzed. It will be interpreted in the form of potential impacts. This step aims to express the potential impacts in the form of analysis which is useful as the
research outputs and is understood by users. Impact analysis types are grouped by considering degredation of abiotic and biotic resource, global warming,
acidification, eutrophication, and toxicity level Cowell, 1999.
In general, LCIA focuses on the relationship between LCI and LCIA steps, for example on how environmental burdens will contribute to potentially arise
environmental impacts, before eventually giving effects to ecosystem survival midpoint damage. The example of problem-oriented method is CML Baseline.
The next method is damage-oriented method. It focuses on the endpoint damage which caused by environmental burdens and impacts. Commonly used damage-
oriented methods are EPS 2000 Steen, 1999 and Eco-Indicator 99 Goedkoop and Spriensm, 2001 and Doka, 2007.
LCA depends on data availability and reliability. Therfore, it requires sensitivity analysis to indentify the effect of data variability, uncertainty, and the
deficiencies in final results which leads to determination of reliability. General approaches to compile the information about the extent human activities take
place activity data or AD with coefficient of emission-measurement or absorption per unit activity. It is called emission factor EF. Basic equation of EF
is displayed in Equation 4.1.
Emission = AD EF 4.1
Where :AD : Activity data; EF : Emission factor
Method Time and Place
The research was conducted in Heat and Mass Transfer Laboratory, Department of Mechanical Engineering and Biosystem, Faculty of Agricultural
Technology, started from July 2012 to January 2013. Measurement Tools and Impact Analysis
Impact assessment life cycle impact assessmentLCIA was conducted using MiLCA-JEMAI software Multiple interface Life Cycle Assessment-Japan
Environmental Management Association for Industry version 1.1.2.5 regular license using data inventory collected in LCI stage in Chapter 3. Calculation
process scheme in this research is displayed in Figure 4.1. The software refers to ISO 14040 as international standard of LCA study. However, the researcher using
the available data in Indonesia in life cycle inventory stage.
Figure 4.1 Calculation procedure by MiLCA-JEMAI
Stages of work that needs to be done using MiLCA-JEMAI software are: Project information, Product system, Inventory analysis, Impact assessment,
Interpretation, Reporting, and Expert review, which is displayed in Figure 4.2. Standard operational procedure to operate MiLCA-JEMAI software is shown in
Appendix 9.
Figure 4.2 Display of MiLCA-JEMAI software version 1.1.2.5
Global warming potential
Acidification
Eutrophication
Waste
, landfill volume
Energy consumption Calculation by Software MiLCA
- JEMAI
INPUT PROCESS
OUTPUT :
Incecticide Methanol
Etc MATERIAL
ENERGY
Electricity, Fertilizerr,
Kategori