C1V220 Urban Engineering Ecology

Fall 2018 Final Exam

Instructors: Husein Almuhtaram and Helen Stopps

Name:

Student Number:

TEST INSTRUCTIONS: Answer all questions on the exam sheets provided. Use the back of the sheets if required. Attempt all questions; there is no penalty for an incorrect answer. If there is any doubt in interpreting a question, state any assumptions made along with the answer as no content questions will be answered during the midterm.

EXAM AIDS: Non-programmable scientific calculator Ruler

Marking scheme

Part 1 (5)

Part 2 (56)

Part 3 (24)

Part 1: Definitions 1. In one or two sentences each, define 5 of the following 7 terms. If more than 5 answers are provided, only the first five will be graded. (5)

Biochemical oxygen demand (BOD)

Parasitism

Acid Rain

Pollution Prevention

Industrial Symbiosis

Urban Canyon

Albedo

Part 2: Short answer questions

2. List and describe the five stages of succession. (5)

3. The Streeter-Phelps equation as derived in class estimates the oxygen deficit in a stream using the difference between the rate of oxygen consumption and the rate of reaeration. What are some other reactions that affect the oxygen concentration in streams? How significant can they be with respect to the oxygen deficit? Provide an example of a wastewater treatment process that would reduce the impact of one of the other reactions you listed. (5)

4. Show that during the initial growth stage of a population, the exponential and logistic growth models are approximately equal. What are the underlying assumptions that cause the models to eventually diverge? (5)

5. Suppose human activity in an ecosystem results in habitat fragmentation. What are the four types of metapopulations that might occur as a result? What are their defining features? Assuming continued human activity (construction, agriculture, land use, etc.) reduces the connectivity of the ecosystem over time, how would the structure of the metapopulation change? (5)

6. What is an Urban Heat Island? Why does it occur? (5)

7. How is climate change affecting Pteropods (sea snails)? What wider impacts might this have on ocean ecosystems and humans? (5)

8. Urbanization reduces water infiltration and increases runoff. What impacts do these changes to the natural hydrologic cycle have on the ecosystem? (5)

9. Consider the material flow diagram of Dysprosium in magnet applications in the EU below.

(a) What are the total dyprosium imports and exports from the system? (2)

(b) What is the efficiency of dyprosium use in the manufacturing process? (2)

(c) If you wanted to reduce dyrprosium imports to the EU, which process would you look into first? (1)

10. The Global Warming Potentials (using carbon dioxide as the reference gas) for selected gasses are shown in the table below.

GWP values and lifetimes from 2013 IFCC AR5 p714 Lifetime (years) L._....... ...........

.

GWP - ...........

(with climate carbon feedbacks) 20 years 100 years

Mtfle 12.4 1 86 1 34

HFC-134a (rdofIuorocarbon) 13.4 3790 1550

CFO-11 (C hlorc fluorocarbon) 45.0 17020 5350

Nitrous oxide (NO) 1210 268 298

Carbon tetrafluoride (OF4) 50000 4950 7350

a) Which gas impacts the Earth's Radiative Forcing the most per kg? (2)

b) You are the manager of a production plant. You have the option to release 5 kg of methane or 100 kg of carbon dioxide, which option would you choose? Show Why. Assume you want to reduce the impact of your production on the Earth's radiative balance. (3)

11. Discuss the potential to use wetlands for wastewater treatment. In what circumstances would wetland treatment be appropriate? What are the limitations of natural wetlands? Describe two constructed wetland designs and their advantages and limitations. (5)

12. Consider neighbourhoods A and B described below.

Neighbourhood A:

- Located within downtown Toronto - Dwelling density of 40 dwellings per hectare - Most houses constructed in 1930s

Neighbourhood B: - Located in a Toronto suburb - Dwelling density of 19 dwellings per hectare - Most houses constructed in 2000s

a) Which neighbourhood would you expect to have lower transportation energy use per capita? Why? (2)

b) Which neighbourhood would you expect to have lower building energy use per capita? Why? (2)

c) You are asked to suggest one way to reduce energy use in either or both neighbourhoods. What do you suggest and why? (2)

Part 3: Calculations

13. a) Wastewater is subjected to a 5-day BOD lab test. The result shows an oxygen consumption of 48 mg/L after 5 days. What is the ultimate BOD of this sample when it is discharged at 16°C? Assume k1 at 20°C is 0.15 day* (3)

b) This effluent is discharged at 4.5 m3/s and has a dissolved oxygen concentration of 1 mg/L.

The receiving stream has a minimum flow of 32 m3/s with an upstream dissolved oxygen concentration of 8 mg/L, an upstream temperature of 12°C, and an upstream BOD of 6 mg/L.

Assume that at 2000k1 = 0.15 day-1 and k2 = 0.25 day-1 downstream of the discharge. What is the minimum dissolved oxygen concentration in the river? Can a fish population survive at this dissolved oxygen concentration? (7)

14. Consider the CO2 emissions given in the table below for two vehicles: a Gasoline Vehicle and an Electric Vehicle. (8)

Life Stage/Process Gasoline Vehicle Electric Vehicle Note CO2 Emissions CO2 Emissions

Vehicle Production 8000 kg 12000 kg

Vehicle Operation 0.238 kg/km 0.081 kg/km Lifecycle emissions for gasoline or electricity production and transport

Vehicle Maintenance 800 kg 800 kg Total Lifetime maintenance

Vehicle Disposal 350 kg 310 kg

a) Assuming the car's lifespan is 10 years and will be driven 20,000 km/year, what are the total carbon dioxide emissions over the lifespan for both vehicles? Which car has less environmental impact (only considering 002 emissions)? (3)

b) The fictional province of Carbonium needs to replace its fleet of 400 service vehicles. Carbonium wants to reduce its GHG emissions. The average car in the Carbonium fleet is driven 1,500 km per year. Which type of car should the province purchase? (3)

c) Name one other process that might contribute to a car's life cycle emissions (in addition to those listed in the given chart). (1)

d) If the values listed in the table for 002 emissions per km travelled were calculated for a region where electricity is supplied by nuclear generation, how would these values change if we wanted to consider a region where electricity is supplied by coal generation instead? (1)

15. A house in Regina had a total energy use of 160,000 MJ in 2017. 30% of this energy was used to power lights and appliance, 25% was used for water heating and the remainder was used for space heating. If Regina had 5835 Heating Degree Days in 2017 and is expected to have 6375 Heating Degree Days in 2019, estimate the total energy use of the house in 2019. (6)

Equation Sheet

i' N dN 1K - N Shannon-Weaver &

dt K Index:

N = N expr•t) N = KNexp(r t)

H' = — P 114)1

K — N0 +N0 exp(r.t)

Dominance Index:

cIN1 K1

(K. —iN,)—N1 dN -

S

J —bN—dN—a'(W D=

dN2_rNI

Pi

(K21)N2 dt K.

BODE = L0 (1 - e_1t) D = k1L0

(e_k16H - e_Ic2GH) + D0e_k2 k2 - k1

kiT, = k1200T2_20 = ki Loe_klt

D0 =C —00 * 1 (1 D0(k2-k1)')1k2_k14k2 k

! k1L0

Dc ='-L0 exp{—k1O]

QrXr + Q.4 = (Qr + QW )XO

XP xf

ii/i!!tp?

fa.,x(t)dt

GWP(x)=

fa,r(t)dt

'ii liig 'g

£uilr heiig

I I +1. Eiampoa £itflT £.jn'iJi

XP x11 x/j X