Question:
LIFE-CYCLE COST ASSESSMENT
Jackman Cleanser Division produces surfactants, ingredients used in producing laundry detergents. (Surfactants are the components that help release soil from clothing.) It is possible to make different types of surfactants, depending on the nature of the material input. One possibility, for example, is to use petrochemical stock as the primary material input. Another possibility is the use of beef tallow as the primary material input.
The primary input plus other inputs and energy sources are used to produce the surfactants. An inventory analysis produces the following for the production of surfactants:
|
|
Petrochemical
|
Tallow
|
|
Materials (kg per 1,000 kg of surfactant)
|
900
|
850
|
|
Water usage (kg per 1,000 kg of surfactants used)
|
50
|
500
|
|
Energy usage (kilowatt-hours per 1,000 kg of surfactants):
|
|
|
|
For production of materials
|
55
|
30
|
|
Transportation
|
10
|
20
|
|
Processing (production of surfactants)
|
60
|
60
|
|
Residues (emissions per 1,000 kg of surfactants):
|
|
|
|
Particulates (air contaminant)
|
2
|
12
|
|
Hydrocarbons (air contaminant)
|
40
|
30
|
|
Dissolved solids (liquid contaminant)
|
6
|
4
|
|
Land contamination (solid residue)
|
80
|
160
|
The greater water usage for tallow relates to the requirement that water must be used to produce feed for beef. The cost per kilogram of petrochemical stock is $0.40. The cost per kilogram of tallow is $0.60. Water costs $0.50 per kilogram, and energy is $1.20 per kilowatt-hour. When air contaminants exceed five per 1,000 kilograms, pollution control equipment must be purchased and installed. The cost of acquiring and operating this equipment is $500 per five units of contaminants. Liquid contaminants are more trouble. If dumped into local streams over the life cycle, the costs are estimated to be $120 per unit of liquid contaminant. If a water treatment system is used, the cost is $60 per unit of contaminant. Finally, soil cleanup is estimated at $20 per unit of solid residue.
Required:
1. Assess the relative environmental impacts of the two approaches to producing surfactants using only operational environmental measures. Which of the two approaches would you recommend? Justify your choice.
2. Use the cost information and calculate an environmental impact cost per 1,000 kg of surfactants. Which of the two approaches would you now recommend? Does the life-cycle cost approach have limitations? Explain.
3. Which parts of the life cycle described by the inventory analysis are controlled by the supplier? By the producer? What part of the inventory analysis is missing?