Learning Objective: Describe the
elements and structures of a
typical wastewater collection
system
A.
Main sewer
B.
Submain sewer
C
Building sewer
D.
Force main
E.
Inverted siphon
Figure 2D
IN ANSWERING QUESTIONS 2-52 THROUGH 2-55,
SELECT FROM FIGURE 2D THE SYSTEM ELEMENT
OR STRUCTURE THAT BEST SATISFIES THE
CONDITION GIVEN AS THE QUESTION.
2-52.
May be less than 8 inches in
diameter.
1. A
2. B
3. C
4. D
2-53.
May receive affluent from a branch
sewer plus a lateral.
1. A
2. B
3. C
4. E
2-54.
Designed to flow full and under
pressure.
1.
A only
2.
A and D
3.
D only
4.
D and E
2-55.
Also called a trunk sewer.
1. A
2. B
3. C
4. D
2-56.
For gravity piping in general, the
gradient should be such that the
wastewater moves at what minimum
rate of speed?
1.
1 foot per second
2.
2 feet per second
3.
3 feet per second
4.
4 feet per second
2-57.
What system elements or structures
should be placed at all locations
where wastewater piping changes
direction, grade, or size?
1.
Force mains
2.
Inverted siphons
3.
Manhole
4.
Intercepting sewers
2-58.
When, if ever, is it permissible to
run a sanitary sewer line and a
water line in the same trench?
1.
When the water line is
installed 3 feet below the
sewer line
2.
When the sewer line is
installed 3 feet below the
water line
3.
When the water pipe is encased
in a concrete sleeve
4.
Never
2-59.
When an engineer determines the
design flow of a sewer line, what
two factors are sometimes combined
by addition?
1.
Daily flow and peak flow
2.
Average usage and daily flow
3.
Peak flow and infiltration
allowance
4.
Daily flow and infiltration
allowance
2-60.
In wastewater system design, the
average daily flow is based on an
average per capita usage of how
many gallons of water per day?
1.
75
2.
100
3.
150
4.
200
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