Environmental Engineering Reference
In-Depth Information
Boundary 1
Resources
Production of raw
materials
Emissions
Transportation
Boundary 2
Processing
Resources
Packaging
Emissions
Storage
Transportation
Boundary 3
Distribution
Resources
Consumption
Emissions
Waste management
Figure 4.4
Flow diagram of a generic food product life cycle showing three independent boundaries.
Production of the raw materials, Boundary 1; processing, Boundary 2; distribution and consumption,
Boundary 3.
Table 4.2 presents some examples of goals and scopes, functional units, and boundaries of
selected LCAs.
Life cycle inventory analysis
After goal-and-scope definition and boundary-setting, the next step is making an inventory of all
inputs and outputs that are relevant to the system and are in the set boundary. The ISO
14044:2006 recommends following a systematic approach to decrease the risk of misunder-
standings and double counting of inputs or outputs (ISO, 2006b). This systematic approach
includes but is not limited to a detailed flow chart that shows the interconnections of the process.
Inputs in data collection are renewable and nonrenewable energy, raw materials, water, and
so on. Outputs include products; co-products; environmental releases to air, including carbon
dioxide, methane, sulfur oxide, carbon monoxide, and NO
x
; effluents released to water and
soil characterized by total suspended solids (TSS), biological oxygen demand (BOD), chemi-
cal oxygen demand (COD), and chlorinated organic compounds (AOXs); and generation of
solid waste, including municipal solid waste and landfills (Roy et al., 2009).
Once the inputs and outputs are identified, their magnitude in numerical terms needs to be
established. Sources of data include: meter readings from equipment, equipment operating
logs or journals, industry data reports, results from laboratory testing, industry databases,
government documents, journals, papers, books, trade associations reports and, best engineer-
ing judgment, among others (EPA, 2006). Data on transport, extraction or raw materials,
