Sustainable Development and Environmental Stewardship (ENGR 202)
Final Exam – Winter 2024
Date: April 26, 2024 Time: 3 hours
Grading: 100 pts.
Weight: 40% of the total course grade
INSTRUCTIONS
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Do not start until instructed by the invigilator.
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If you believe there is an error in a question, make an assumption and continue based on that assumption. Be sure to
argue your assumption clearly in writing to have a chance at partial credit.
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This exam is closed book.
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ENCS Faculty-approved calculator may be used.
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The invigilators will not attempt to interpret or clarify a question, only handle administrative issues.
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The exam has 23 questions.
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You must take the exam paper with you when you are finished. Only submit the booklet with your responses!
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GOOD LUCK!
1. A) Name the three aspects (triple bottom line) of sustainability. (3 points)
B) An agricultural facility has created a novel technology for increasing production yield on the same
land area while lowering production costs. However, because of the complexity of the process, they
experience more workplace accidents. Which aspect(s) of sustainability are improved by the use of
this technology, and which are jeopardized? (3 points)
2. How much energy (MJ) is released when there is 10g of mass defect? What is the equivalent amount
(kg) of natural gas combustion? The heating value of natural gas is 50 MJ/kg. (6 points)
3. True or false? “The majority of municipal wastes in North America is recycled”. (2 points)
4. Which of the following case studies were relevant to the “Land Pollution”? (2 points)
(a) Chernobyl
(b) Love Canal
(c) New York City Smog
(d) Aral Sea
(e) Ontario Land Disaster
5. Calculate the (a) waste composition and (b) Feed flowrate in the following separation units (all
percentages are in mass). (6 points)
Feed, 1000 kg/h
-30% MeOH
-70% Water
Product, 200 kg/h
-90% MeOH
-10% Water
Separation
Waste
-?% MeOH
-?% Water
(a)
(b)
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6.
(8 points) A company that produces pens is interested to perform a life-cycle assessment of their
product. They provide you with the following data:
TABLE 1: PEN ASSEMBLY (UNIT PROCESS) DATA
Pen
Pen body
Ink
CO2
SOx
NOx
1 unit
-1 unit
-4 mL
0g
0g
0g
TABLE 2: PEN BODY PRODUCTION (UNIT PROCESS) DATA
Pen
Pen body
Ink
CO2
SOx
NOx
0 unit
100 unit
0 mL
40 g
1.2 g
0.3 g
TABLE 3: INK PRODUCTION (UNIT PROCESS) DATA
Pen
0 unit
Pen body
0 unit
Ink
50 mL
CO2
22 g
SOx
0.05 g
NOx
0.21 g
a. For a functional unit of ‘Production of 12 pens’, calculate the life-cycle inventory.
b. Which data would be considered reference flows?
7. A company approaches you to perform a life-cycle assessment on their product, a bottle of hand
sanitizer. In particular, they are interested in comparing it to a system that uses ultra-violet light to
sanitize hands. Propose a good function and functional unit for the study. (5 points)
8. What is ‘burden-shifting’ and how does LCA help to avoid it? (4 points)
9. What are the three questions that should be addressed in the ‘goal’ of an LCA? (3 points)
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10. (8 points) A driver would like to travel from Montréal to the Laurentides Wildlife Reserve, which
is located approximately 300 km from Montréal. The vehicle consumes 6L of fuel per 100 km. If
they were required to pay $80 for each tonne of CO2 that they produce, how much would they pay
for this journey? Assume the fuel is 100% octane (C8H18), undergoes complete combustion in the
engine and has a density of 0.755 kg/L. Several atomic weights are found in Table 4.
TABLE 4: USEFUL ATOMIC WEIGHTS
Carbon
12 g/mol
Hydrogen
1 g/mol
Oxygen
16 g/mol
Nitrogen
14 g/mol
11. (8 points) An abridged inventory of a product system translated to midpoint impacts is given in
Table 5. The ReCiPe impact assessment methods gives the characterization factors shown in Table
6 (abridged).
TABLE 5: ABRIDGED INVENTORY OF A PRODUCT SYSTEM
Species
HCFC-142b
CFC-114
PM2.5
NH3
PO43Phosphorus
Nickel
1,4 Dichlorobenzene
Quantity
81.47
16.44
2.33
1562
4450
2916
1518
1672
Unit
kg CFC11 to air
kg CFC11 to air
kg PM2.5 to air
kg PM2.5 to air
kg P to freshwater
kg P to freshwater
kg 1,4-DCB to industrial soil
kg 1,4-DCB to industrial soil
TABLE 6: ABRIDGED RECIPE CHARACTERIZATION FACTORS
Category
Midpoint to endpoint
characterization factor
Ozone depletion
2.4 ∙ 10-4
Particulate matter formation 6.3 ∙10-4
Eutrophication
6.1∙10-7
Terrestrial toxicity
5.4 ∙10-8
a.
b.
c.
d.
Unit
DALY/ kg CFC11 to air
DALY/kg PM2.5 to air
PDF∙m2∙yr/kg P to freshwater
PDF∙m2∙yr/kg 1,4-DCB to
industrial soil
What is the total damage to human health?
If the company wanted to make efforts to protect human health, what should they focus on?
What is the total damage to ecosystem quality?
If the company wanted to make efforts to protect ecosystems, what should they focus on?
12. (6 points) A utility company would like to install a water turbine that to generate 50 MW of
electricity. You may assume the density of the wind and water to be 1 kg/m3 and 1000 kg/m3
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a. What is the smallest turbine diameter that would be required if the water has a velocity
of 5.2 m/s?
b. If the company wanted to install wind turbines with a diameter of 80m, what is the
minimum number that they would need if the average wind speed is 8 m/s?
13. (4 points) Describe what is meant by ‘combined heat and power’ and why it is a popular technology
for new projects.
14. (4 points) Rank these technologies in increasing order of their CO2 footprint per kWh of electricity
provided: natural gas power plant, natural gas combined cycle power plant, nuclear power plant,
coal power plant.
15. (2 points) Is the following statement true or false?
“LCA makes decisions about which product should be used, according to its environmental impact.”
16. For the following flows, indicate whether they are elementary or intermediary flows (8 points)
a. Rubber particles from friction between the road and a car tire
b. Iron ore, in the ground at a mine site
c. Potatoes at a market stall
d. Lumber used in building a house
e. Gold used in microchip fabrication
f. Water in a river
g. Cement to build a hydroelectric dam
h. Jet fuel
17. In LCA, where should important quality characteristics be accounted for? (2 points)
a. Goal
b. Scope
c. Inventory
d. Impact assessment
e. Interpretation
18. Scaling elementary flows to the functional unit is part of which phase of LCA? (2 points)
a. Goal
b. Scope
c. Inventory
d. Impact assessment
e. Interpretation
19. Explain the classification step of LCIA (3 points)
20. Can an emission have more than one characterization factor? Explain why or why not. (4 points)
21. If 20 people have their expected lifetime in good health reduced by 6 months, how many DALYs is
this? (3 points)
22. What is the main reason for doing the impact assessment step of LCA? (4 points)
23. Electric vehicles have the potential to reduce human contributions to climate change. Are there any
ethical issues (or other issues) associated with electric vehicles? If so, describe one such issue. (4
points)
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