Environmental Engineering - Essay Prowess

Environmental Engineering


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Name: _______________________________________
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Final Exam – CE 2633: Environmental Engineering
Due December 11 noon, 2009
Multiple Choice (50 points – 5 points per question, circle all that apply)
1. Which of the following statements are true concerning the Safe Drinking Water
Act secondary standards?
a. They are enforceable.
b. They are for compounds which make drinking water aesthetically pleasing
to consumers.
c. They enable drinking water to be potable.
d. They enable drinking water to be palatable.
e. All of the above.
2. A pollutant which degrades according to the equation dC/dt = -kC is said to react
according to?
a. Zero order kinetics.
b. First order kinetics.
c. Second order kinetics.
d. None of above.
e. All of the above.
3. Recarbonation is necessary in drinking water treatment because:
a. The chemicals added during water treatment reduce the pH.
b. The chemicals added during water treatment increase the pH.
c. The chemicals added during water treatment consume carbon dioxide.
d. All of the above
e. None of the above
4. If the current mineral reserve of iron is 65,400 Tg, the annual demand is 1060 Tg
and we assume the demand increases 1.2% annually, how long will the reserve
a. 62 years
b. 73 years
c. 55 years
d. 46 years
e. None of the above
5. A solution that has a [OH-] concentration of 10-3 M has a pH of
a. 11
b. 7
c. 3
d. 10
e. -3
f. 12
Name: _______________________________________
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6. A dual media rapid sand filter used what two types of porous media for screening
of small-sized particulate matter
a. Anthracite coal
b. Garnet
c. Gravel
d. Sand
e. Clay
7. The unit process that is used primarily for the removal of settleable solids such as
coffee grinds and sand is:
a. Comminutor
b. Primary settling tank
c. Grit chamber
d. Secondary clarifier
e. Bar screen
8. The hardness of water is most commonly due to the presence of
a. CO3
b. HCO3

c. Ca2+
d. Mg2+
e. Clf.
All of above
g. None of the above
9. The single-most important purpose of secondary treatment is
a. Removal of suspended solids
b. Removal of suspended BOD
c. Removal of soluble BOD
d. Denitrification
e. Nitrification
f. All of above
10. The purpose of disinfection in drinking water treatment is/are concentration of 10-
a. Kill pathogens
b. Keep residual chlorine to the end point of the consumer
c. More palatable water
d. Prevent disinfection by-products
e. Reduce the turbidity
Name ____________________________Student No. ____________________________
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Short Answers (10 points – 10 points per question)
1) Below (in problems I-VII) are listed the abbreviations for several of the major
regulations discussed in CE 2633 and the major topics covered by these regulations.
Match the regulation with its description.
___I. SARA A) established primary regulations for the protection of public
health and secondary regulations related to the esthetic
properties of drinking water
___II. RCRA B) provides for liability, compensation, cleanup and emergency
response for hazardous substances released into the
environment and for the cleanup of inactive hazardous waste
disposal sites
___III. HSWA C) control of waterborne toxic substances and formation of
NPDES permits
___IV. CAA D) directed the US EPA to establish hazardous waste regulations
which define, classify and regulate the generation and disposal
of hazardous wastes
___V. SDWA E) created, in part, in response to concerns that existing methods
of hazardous waste disposal were not safe; sets restrictions on
the land disposal of specific wastes (commonly referred to as
the “Land Ban”)
___VI. CERCLA F) reaffirmed previously enacted legislation; clearly a preference
for remediation technologies that rendered a waste
nonhazardous (rather than just transferring it from one disposal
site to another or simple containment on site)
___VII. CWA G) established the NAAQS, required states to submit SIPs that
would show how they would meet these standards; required
NSPS to be established which would limit emissions from
certain types of industrial facilities.
2) Define the following terms
a) Steady state condition
b) Conservative pollutant
Name ____________________________Student No. ____________________________
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3) Draw a schematic of a typical secondary wastewater treatment plant using activated
sludge treatment. Indicate where sludge are produced and where gases are added
4) What is “purple pipe”? (Guest speaker lecture)
5) What is nitrification and denitrification? (List chemical reactions too)
Name ____________________________Student No. ____________________________
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6) List five of six major air pollutants for which the US EPA has designated air quality
7) Identify the water treatment process (from the list below) that is most likely to be
used to (hint: you only need to pick 4 out of 12 choices):
i) protect the general public from dental caries _____
ii) remove turbidity _____
iii) protect the general public from waterborne diseases ____
iv) reduce the pH following softening ____
A) softening
B) flocculation/ coagulation
C) alkali addition
D) recarbonation
E) disinfection
F) bar screens
G) low-lift pumps
H) high lift pumps
I) fluoridation
J) distribution
K) filtration
L) activated sludge
8) There are two sludge treatment processes, one use sludge retention time of 3 days
(θc=3 days), they other use sludge retention time of 10 days (θc=10 days), which
process cost more for sludge proposal? And why?
Name ____________________________Student No. ____________________________
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9) If a hazard index is 0.001 (HI=0.001), what does this number mean to you as an
environmental engineer? (For example, is there any potential healthy effect?)
10)Among alpha, beta, gamma and x-ray, what are the most dangerous internal radiation
hazards? Why?
Name ____________________________Student No. ____________________________
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Part III – Problems
Problem 1 – Alkalinity (40 points)
A water has a pH of 5.66 and the concentration of HCO3
– is 0.658 mg/L. What is the
exact alkalinity of the water in units of mg/L as CaCO3?
Name ____________________________Student No. ____________________________
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Problem 2 – Water quality in river (60 points)
Using the data given below:
a) calculate the DO deficit just after mixing of the plant waste water with the water
in the river.
b) calculate the time (days) required for the deficit to reach its maximum value
Deadly Chemical Plant Babbling Run
(upstream from outfall)
Flow, m3/s 0.33 5.67
ult-BOD at 20 oC, mg/L 450 1.05
DO, mg/L 0.0 8.3
kd, at 20 oC, day-1 N/A 0.22
kr, at 20 oC, day-1 N/A 0.78
speed, m/s N/A 0.55
T, oC 20 20
DOsat, mg/L, 20 oC N/A 9.17
N/A = not applicable