CVG 2132
Fundamentals of Environmental Engineering
MIDTERM 2021
Professor: C. Kinsley
GIVEN NAME: ________________________________________
SURNAME: ___________________________________________
STUDENT NUMBER: ____________________________________
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13 PAGES
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OPEN BOOK EXAM (NO INTERNET!)
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READ THE QUESTIONS CAREFULLY
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ANSWER THE QUESTION DIRECTLY ON MIDTERM OR ON SHEETS OF BLANK PAPER OR ON A
TABLET
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BE MINDFUL OF TIME LIMIT
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TOTAL MARKS = 70
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WRITE LEGIBLY AND NEATLY
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CLEARLY STATE ALL ASSUMPTIONS
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WHEN COMPLETED UPLOAD ONE PDF DOCUMENT WITH THE QUESTIONS IN ORDER TO
BRIGHTSPACE (14:40 TIME LIMIT)
GOOD LUCK!
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SECTION 1. (15 marks) MULTIPLE CHOICE QUESTIONS Provide one answer to each multiple-choice
questions in the space provided below.
Question
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Answer
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4
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Q1. (3 marks) Which of the following is NOT an example of the Tragedy of the Commons?
a) Depletion of organic matter in the soil on a farm
b) Depletion of ocean fish stocks
c) Traffic congestion
d) Global warming
e) All are examples of the Tragedy of the Commons
Q2. (3 marks) A 0.6 kg rock sample contains 2.5 ppm gold. How many mg of gold are there in the
sample?
a) 0.42 mg
b) 4.2 mg
c) 0.15 mg
d) 1.5 mg
e) 2.5 mg
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Q3. (3 marks) You are conducting a tracer study in a CSTR using a pulse injection to determine the
hydraulic retention time (τ). Which statement do you expect to be true?
a) When the concentration C/C0 increases to 1; τ = t/4
b) When the concentration C/ C0 decreases to 0; τ = t/4
c) When the concentration C/ C0 increases to 1; τ =t
d) When the concentration C/ C0 decreases to 0; τ =t
e) none of the above
𝐿2
Q4. (3 marks) The rate constant for a reaction is given as 12 𝑚𝑔2 ∙𝑑. The reaction order is:
a) a zero-order reaction
b) a first order reaction
c) a second order reaction
d) a third order reaction
e) a fourth order reaction
Q5. (3 marks) Microorganisms that feed on inorganic carbon as a carbon source, inorganic nitrogen as
an electron donor, and oxygen (O2) as an electron acceptor are classified as:
a) Aerobic, chemotrophic, lithotrophic, autotrophs
b) Anoxic, phototrophic, lithotrophic, autotrophs
c) Facultative, chemotrophic, lithotrophic, heterotrophs
d) Aerobic, chemotrophic, organotrophic, heterotrophs
e) Anoxic, chemotrophic, organotrophic, heterotrophs
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SECTION 2. (55 marks) CALCULATION QUESTIONS
Q1. (16 marks) A potential well water source was characterized with the following parameters:
Constituent Concentration Molecular Weight
mg/L
g/mol
Ca2+
65.0
40
Na+
95.0
39
Al3+
5.0
27
HCO3-
74.0
61
CO32-
6.0
60
Concentration
mg/L as CaCO3
a) (5 marks) Fill in the last column in the table above by calculating the concentration of each
water quality constituent in units of mg/L as CaCO3. Show at least one sample calculation.
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Additional space for Q1a)
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b) (5 marks) If the pH is 10.22, calculate the alkalinity of the water as CaCO3.
c) (2 marks) Calculate the total hardness of the water as CaCO3.
d) (4 marks) If only one constituent is missing from the analysis, is it a cation or an anion and what
is its concentration in mg/L as CaCO3?
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Q2. (5 marks) You collect a sample of wastewater and bring it back to the lab for analysis. You filter 250
mL of sample through a 1.5 µm filter and place the filter in a weighing tray in the oven at 105°C. After
weighing the filter, you place the filter in the muffle furnace at 540°C. Calculate the Total Suspended
Solids (TSS), Volatile Suspended Solids (VSS) and Fixed Suspended Solids (FSS) of the sample in mg/L
using the lab data given below. What percentage of the solids can be considered as organic matter?
Item
Weighing tray + filter
Weighing tray + filter + filtered sample after drying at 105°C
Weighing tray + filter + filtered sample after ignition at 540°C
Mass
1.500 g
1.590 g
1.520 g
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Q3. (10 Marks) A desalination RO membrane system is operating with influent saltwater flow of 1000
m3/hr, 30,000 mg/L of salt and density of 1030 kg/m3. The brine solution has a flowrate of 150 m3/hr
with a density of 1150 kg/m3. If the outlet concentration is 50 mg/L find the concentration of the brine
solution as well as the outlet flowrate. Make a schematic of the system and state all assumptions.
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Additional Space for Q3.
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Q4. (10 marks) A cheese production facility in Winchester Ontario is having problems meeting the
Provincial discharge limit of 25 mg/L BOD5. The facility produces and discharges 200 m3/d of wastewater
with an influent concentration of 5,000 mg BOD5 /L. The current well mixed aerated lagoon has an
operating volume of 10,000 m3. What is the effluent concentration with the current system? What
increase in volume is required to meet the discharge limit? The kinetic rate for BOD reduction is 0.5 d-1.
State any assumptions.
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Q5. (14 marks) There is a 5000 m3 spill of 1000 mg/L radioactive Xenon from the Chalk River Nuclear
Facility into a 2 x 106 m3 reservoir on the Ottawa River. The Reservoir is 200 km from Ottawa. Xenon can
be considered as non-reactive given its long half-life. The reservoir can be considered as a CSTR while
the river can be considered as a PFR. At the time of the spill the velocity of the river is 0.2 m/s and the
flow is 2000 m3/s. Calculate a) the time for the radioactive material to reach Ottawa and b) once the
contaminated water reaches the City, how long it will take for the concentration to decline to an
acceptable limit of 0.01 mg/L. State all assumptions.
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Additional Space for Q5.
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Individual Exam
I submit this exam and attest that this work conforms to the regulations on academic integrity of the University of
Ottawa. Specifically, I have NOT consulted with other people, shared questions or answers or used the internet to
search for information or solutions.
_______________________________
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Name, Capital letters
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Signature
Date
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