Streamlined Life Cycle Assessment (Slca) For Comparing Two Products
Streamlined Life Cycle Assessment (Slca) For Comparing Two Products
Life-cycle assessment or LCA is a way of evaluating the total environmental impact of a product through every stages of its life — from obtaining raw materials, such as mining or logging, all the way to factory production, product distribution, retail, use, and disposal, which may include incineration, landfill, or recycling.
The Society of Environmental Toxicology and Chemistry defines LCA as a process to evaluate the environmental burdens associated with a product system, or activity by identifying and quantitatively describing the energy and materials used, and wastes released to the environment, and to assess the impacts of those energy and material uses and releases to the environment.
The assessment includes the entire life cycle of the product or activity, encompassing extracting and processing raw materials; manufacturing; distribution; use; re-use; maintenance; recycling and final disposal; and all transportation involved.LCA addresses environmental impacts of the system under study in the areas of ecological systems, human health and resource depletion.
It does not address economic or social effects. LCA studies the environmental aspects and potential impacts throughout a product’s life (i.e. cradle-to-grave) from raw material acquisition through production, use and disposal.
The general categories of environmental impacts needing consideration include resource use human health, and ecological consequences.In order to understand LCA, it is useful to look at the total material budget from natural resource extraction to production until its return to the reservoir of its origin
Methodological Framework For Streamlined Life Cycle Assessment (Slca) For Comparing Two Products
Phase 1. Goal and Scope Definition
- The purpose of Goal and Scope Definition is to evaluate alternative designs in order to maintain economic feasibility while also seeking to reduce the environmental damage due to the current conventional design.
- It consists of
- Goal
- Flowchart
- Scope
- functional unit
- system boundaries
- Data quality.
GOAL
- The goal of an LCA study shall clearly state the intended application, reasons for carrying out the study and intended audience and user of results
- Examples of goal statements are:
- (1) to compare two or more different products fulfilling the same function with the purpose of using the information in marketing or regulating the use of the products,
- (2) to identify improvement possibilities in further development of existing products or in innovation and design of new products,
Flowchart
- Flowcharting is important in understanding the process under consideration.
- Making the process flow explicitly aids several decisions of the overall analysis
- deciding the scope of the analysis to be performed
- determining what data needs to be collected
- identifying at what point in the process environmental loading originates
- formulation of process alternatives
- judgment regarding streamlining.
Functional Unit
- The functional unit sets the scale for comparison of the two products
- All data collected in the inventory phase will be related to the functional unit.
- When comparing different products fulfilling the same function, definition of the functional unit is of particular importance.
- One of the main purposes of a functional unit is to provide a reference to which the input and output data are normalized.
- A functional unit of the system must be clearly defined and measurable.
- The result of the measurement of the performance is the reference flow.
- Comparisons between systems shall be done on the basis of the same function, measured by the same functional unit in the form of equivalent reference flows.
Data Quality
- The quality of the data used in the life cycle inventory reflects the quality of the final LCA.
- Data quality indicators:
- Precision – measure of the variability of the data values for each data category expressed (e.g. variance).
- Completeness – percentage of locations reporting primary data from the potential number in existence for each data category in a unit process.
- Representativeness – qualitative assessment of the degree to which the data set reflects the true population of interest (i.e. geographic and time period and technology coverage).
- Consistency – qualitative assessment of how uniformly the study methodology is applied to the various components of the analysis.
- Reproducibility – qualitative assessment of the extent to which information about the methodology and data values allows an independent practitioner to reproduce the results reported in the study.
Phase 2. Inventory Analysis
- Inventory analysis is the second phase in LCA.
- The possible life cycle stages for consideration are:
- (1) Pre-manufacturing: raw material acquisition or resource extraction, component manufacture, material manufacture;
- (2) Manufacturing: material processing and product assembly;
- (3) Product delivery: filling, packaging, shipping, and distribution;
- (4) Customer use, reuse, and maintenance (including storage and consumption),
- (5) Recycling and waste management,
- (6) Disposal.
Inventory analysis includes data collection, validation, relating data to the specific system, allocation, and recycling
Data Collection
The inventory analysis includes collection and treatment of data to be used in preparation of a material consumption, waste, and emission profile for all the phases in the life cycle. The data can be site specific or more general. Inventory analysis also involves calculation procedures to quantify relevant inputs and outputs of a product system.
These inputs and outputs may include use of resources and releases to air, water and land associated with the system. The process of conducting an inventory analysis is iterative. For each of the life cycle stages under consideration, using the process flowchart as a guide, data must be collected about the inputs and outputs of each stage.
These inputs and outputs may include materials (both raw and processed), energy, labor, products, and waste. In the event of multiple sub-processes being grouped together as a single life cycle stage, the data about each sub-process must be aggregated to produce a computed value (e.g. overall water use) for the whole stage.
In addition, materials, energy usage, and waste produced from a specific sub-process might be an aggregate of not one, but several products produced at that point. In this case, the data must be handled carefully to ensure that the allocation of the proportion of each input and output stream to each co-product is correct (usually done by weight). Raw data collected must be converted, via the base unit and analysis time frame, to a “stand alone” state suitable for use in the analysis.
Validation of Data
Data validation has to be conducted during the data collection process. Systematic data validation may point out areas where data quality must be improved or data must be found in similar processes or unit processes. During the process of data collection, a permanent and iterative check on data validity should be conducted. Validation may involve establishing, for example, mass balances, energy balances and/or comparative analysis of emission factors.
Relating Data
The fundamental input and output data are often delivered from industry in arbitrary units, such as emissions to the sewage system as mg metals/liter wastewater The specific machine or wastewater stream is rarely connected to the production of the considered product alone but often to a number of similar products or perhaps to the whole production activity. For each unit process, an appropriate reference flow shall be determined (e.g. one kilogram of material).
The quantitative input and output data of the unit process shall be calculated in relation to this reference flow.Based on the refined flow chart and systems boundary, unit processes are interconnected to allow calculations of the complete system. The calculation should result in all system input and output data being referenced to the functional unit.
Allocation and Recycling
When performing LCA of a complex system, it may not be possible to handle all the impacts inside the system boundary. This problem can be solved either by expanding the system boundary to include all the inputs and outputs, or by allocating the relevant environmental impacts to the studied
The inputs and outputs of the unallocated system shall equal the sum of the corresponding inputs and outputs of the allocated system. Some inputs may be partly co-products and partly waste. In such a case, it is necessary to identify the ratio between co-products and waste since burdens are to be allocated to the co-product only. There shall be uniform application of allocation procedures to similar inputs and outputs of the systems under consideration.
Phase 3. Impact Analysis
Impact analysis is a “quantitative and/or qualitative process to characterize and assess the effects of the environmental interventions identified in the inventory table”.
Impact Categories
The first step in impact analysis is the identification of stressors and impact categories. Stressors are “any chemical, biological, or physical entity that causes adverse affects on ecological components, i.e. individuals, populations, communities, or ecosystems.” The process of identifying stressors is necessary to assessing the environmental impacts (either real or potential). The potential hazards of an operation must be considered, then the investigator must decide which of these hazards are relevant to meet the Goal of the study.
The potential stressors of industrial processes are: raw materials, energy use, air emissions, liquid discharge, solid wastes, radiation, and noise.
- These stressors could impact the following categories:
- Human Health – acute effects (accidents, explosions, fines, safety issues); chronic effects (injury, disease), work environment
- Ecological Health – structure (population, communities), function (productivity, processes), biodiversity (habitat loss, endangered species, eutrophication, photochemical oxidant formation, acidification).
- Social Welfare – economic impact, community impact, psycho-social impact.
- Resource Depletion – biotic resources (agricultural, forest, living species), flow resources (air quality, water quality, global warming, stratospheric ozone depletion), and stock resources (land, energy, and raw materials).
Valuation or Weighting
The weighting of each stressor on the impact category for each life stage may follow integer rating where 0 represents highest impact (a very negative evaluation) and 4 lowest impact (an exemplary evaluation), or qualitative rating of high (H), medium (M), and low (L). Value assignment is arbitrary as an expression of personal preference and priorities. The approach is used to estimate the potential for improvement in environmental performance.
Phase 4. Interpretation
- Interpretation consists of the following steps:
- (1) Identify the significant environmental issues,
- (2) evaluate the methodology and results for completeness, sensitivity and consistency,
- (3) check that conclusions are consistent with the requirements of the goal and scope of the study, including data quality requirements, predefined assumptions and values, and application oriented requirements.
( Sumber: Materi kuliah Biosystem)
