54. The operating point of pump “A” in system “B” is number:
(a) 2 (b) 3 (c) 4 (d) 5 (e) 6
55. The operating point of two pumps “A” in series in system “B” is:
(a) 2 (b) 3 (c) 4 (d) 5 (e) 6
56. The operating point of two pumps “A” in parallel in system “B” is:
(a) 2 (b) 3 (c) 4 (d) 5 (e) 6
57 The shut-off head of pump “A” is:
(a) 1 (b) 2 (c) 3 (d) 4 (e) 5
58. The shut-off of two pumps “A” in series is:
(a) 1 (b) 2 (c) 3 (d) 4 (e) 5
59. The shut-off of two pumps “A” in parallel is:
(a) 1 (b) 2 (c) 3 (d) 4 (e) 5
60. The static head or static lift for the system is:
(a) 1 (b) 2 (c) 3 (d) 4 (e) 5
45
61. The most costly aspect of solid waste management involves its
(a) storage (b) processing (c) disposal
(d) collection (e) none of these
62. The largest component of MSW in the United States is,
(a) garbage (b) paper (c) yard waste
(d) plastics (e) glass
63. Incineration can reduce the total volume of MSW by about
(a) 50% (b) 75% (c) 90% (d) 95% (e) 99%
64. Solid residue remaining in an incinerator furnace after combustion is
(a) soot (b) fly ash (c) bottom ash (d) leachate (e) dust
65. Most large municipal incinerators operate in the _________________ mode.
(a) batch-feed (b) continuous (c) pyrolysis (d) cogeneration
(e) secondary combustion
66. A process in which the organic portion of MSW decomposes under
carefully controlled conditions is called
(a) incineration (b) pyrolysis (c) composting (d) baling
(e) vulcanization
67. A material with one of the highest values as a recyclable one is
(a) iron (b) aluminum (c) paper (d) plastic (e) glass
68. In a sanitary landfill, solid waste is compacted and covered with soil
(a) daily (b) biweekly (c) weekly (d) monthly (e) semiannually
69. An important technical factor for the location of a sanitary landfill is
(a) volume capacity (b) site accessibility (c) site hydrogeology
(d) all of these (e) none of these
70. The TCLP is Used to determine the _________________ of hazardous waste.
(a) reactivity (b) ignitability (c) toxicity (d) corrosivity
(e) all of these
71. Hazardous waste is transported mostly by
(a) trains (b) planes (c) boats (d) trucks (e) all of these
46
72. The manifest system controls the _______________ of hazardous waste.
(a) generation (b) storage (c) transport (d) treatment
(e) disposal
73. A secure hazardous waste landfill must be constructed with
(a) a double impermeable bottom liner
(b) a double leachate collection system
(c) a network of groundwater monitoring wells
(d) an impermeable cap or final cover
(e) all of the above
74. The Superfund program pertains to the
(a) transport of hazardous waste
(b) treatment of hazardous waste
(b) landfilling of hazardous waste
(d) remediation of hazardous waste sites
(e) minimization or recycling of hazardous waste
75. On-site remediation of a hazardous waste site may include
(a) extraction, treatment, and replacement
(b) containment by slurry trench cutoff walls
(c) bioventing
(d) air sparging
(e) any of the above
76. The most desirable solution to the hazardous waste problem involves
(a) deep well injection
(b) incineration
(c) secure landfilling
(d) source reduction and recycling
(e) biological treatment
77. Clean air is composed mostly of
(a) oxygen (b) nitrogen (c) ozone (d) argon (e) CO2
78. The lowermost layer of the atmosphere is called the
(a) ionosphere (b) mesosphere (c) stratosphere (d) troposphere
(e) thermosphere
47
79. The dry adiabatic lapse rate is equal to minus ______ °C/100 m.
(a) 0.5 (b) 1 (c) 1.5 d) 3 (e) 3.5
80. The substance that is not one of the criteria air pollutants is
(a) SO2 (b) NO2 (c) CO2 (d) O3 (e) CO
81. The most abundant of the criteria air pollutants is
(a) SO2 (b) NO2 (c) CO2 (d) O3 (e) CO
82. Photochemical smog is the result of reactions among sunlight and
(a) SO2 and particulates (b) VOCs and O3 (c) VOCs and NO2
(d) smoke and fog (e) SO2 and CO
83. An air pollutant that can possibly cause asphyxiation or suffocation is
(a) SO2 (b) NO2 (c) CO2 (d) O3 (e) CO
84. An air pollutant that causes eye and throat irritation, and coughing is
(a) SO2 (b) NO2 (c) O3
(d) all of the above (e) none of the above
85. One of the most significant “greenhouse gases” is considered to be
(a) carbon monoxide (b) carbon dioxide (c) nitrogen dioxide
(d) sulfur dioxide (e) ozone
86. Global warming due to the greenhouse effect may eventually cause
(a) rising sea levels (b) melting of glaciers
(c) flooding of coastal areas (d) all of these (e) none of these
87. The substance believed to cause depletion of stratospheric ozone is
(a) SO2 (b) NO2 (c) PCB (d) CFC (e) DDT
88. Acid rain is caused primarily by
(a) SO2 and NO2 (b) CO and CO2 (c) particulates and O3
(e) CO and SO2 (e) O3, NO2 and CO
89. Air infiltration rates for new houses in the U.S. are typically about
(a) 0.1 ach (b) 1 ach (c) 5 ach (d) 10 ach (e) 20 ach
48
90. Radon gas is most significant as a(n)
(a) ambient air pollutant
(b) indoor air pollutant
(c) cause of the greenhouse effect
(d) cause of ozone depletion
(e) cause of acid deposition
91. Typical indoor air pollutants include
(a) ETS (b) formaldehyde (c) VOCs (d) all of these
(e) none of these
92. Sampling for ambient particulate measurements is done primarily by
(a) dustfall buckets (b) hi-vol samplers (c) PM10 samplers
(d) Ringlemann samplers (e) cascade impactors
93. Electrostatic precipitators can remove ___________ from dirty air.
(a) sulfur dioxide
(b) nitrogen dioxide
(c) carbon monoxide
(d) ozone and smog
(e) particulates
94. The most efficient of the following air cleaning devices is the
(a) settling chamber
(b) cyclone
(c) baghouse
(d) electrostatic precipitator
(e) spray tower
95. A device used to remove gaseous pollutants from dirty air is the
(a) settling chamber
(b) cyclone
(c) baghouse
(d) electrostatic precipitator
(e) spray tower
96. An FGD system removes ___________ from power plant emissions
(a) SO2 (b) NO2 (c) CO2 (d) O3 (e) CO
49
97. The speed of a sound wave in air is about
(a) 340 Hz (b) 340 ft/s (c) 340 m/s (d) 1100 m/s (e) 1 m/s
98. A combination of two sounds with equal SPL values always results in
(a) a 2-dB increase over the SPL of one source alone
(b) a 10-dB increase over the SPL of one source alone
(c) a doubling of the SPL value of one source alone
(d) not enough information given
(e) none of the above
99. When the SPL values of two noise sources differ by more than dB,
the weaker noise source will not be noticeable due to “masking.”
(a) 3 (b) 10 (c) 15 (d) 20 (e) 25
100. For every 10-dB increase in SPL, sound intensity increases by a factor of
(a) 2 (b) 3 (c) 10 (d) 15 (e) 20
ANSWERS TO MULTIPLE CHOICE QUESTIONS
50
Supplemental Problems
Sketch the drainage divide line for the catchment area tributary to point A on the
topographic map shown below. If the map scale is 1 in. = 200 ft, what is the
approximate area of the catchment area, in acres? If the map scale is 1:2000, what
is the approximate area, in hectares?
51
Supplemental Problems
Sketch the drainage divide line for the catchment area tributary to point A on the
topographic map shown below. If the map scale is 1 in. = 200 ft. what is the
approximate area of the catchment area in acres? If the map scale is 1:2000,
what is the approximate area in hectares?
52
A
total of 8 inches of rain fell on a 300 acre watershed in 6 hours. What was the
average rainfall intensity? What was the total volume of water that fell on the
watershed in that time interval (in ac-ft and cubic feet)?
A total of 200 mm of rain fell on a 100 hectare watershed in 5 hours. What was the
average rainfall intensity? What was the total volume of water that fell on the
watershed in that time interval (in cubic meters)?
A
375 mm diameter pipe placed on a 1% slope flows 80% full. Determine the
discharge and velocity of flow under these partial flow conditions.
A
24 in. diameter pipe placed on a grade of 1 ft per 1000 ft carries a flow of 1500
gpm. What is the velocity and depth of flow in the pipe under these conditions?
53
A lateral sewer is to be designed to receive flow from 30 acres of a city in an area
where the population density is 150 people per acre. If the average per capita flow
rate is assumed to be 100 gpcd, what should be the design flow rate of the lateral,
in gpm and cfs?
A 100 m sewer reach is to have a minimum flow capacity of 200 L/s. The street
elevation at the upper MH is 305.55 m and at the lower MH it is 303.05 m. Select an
appropriate pipe diameter and slope for this reach, and determine the pipe invert
elevations at each MH. Use a cover depth of 2.00 m above the pipe crown.
A
12 in. pipe, an 18 in. pipe, and a 24 in. pipe intersect at a manhole. If the invert
elevation of the 18 in. pipe is 100.00 ft, determine the required invert elevation of the
12 in. pipe and the 24 in. pipe.
A
5 mL water sample was tested for fecal coliforms using the membrane filte
r
method. A total of 34 colonies of fecal coliforms were counted on the filter afte
r
incubation. What was the fecal coliform count?
54
A 12 in. diameter extra strength VCP pipe is to be placed in a 3 ft wide
trench with class C bedding. Backfill is sand and gravel with a unit
weight of 120 pounds per cubic foot. Using a safety factor of 1.5, what is
the maximum allowable depth of the trench?
A steeply sloping 200 acre watershed comprises 150 acres of woods and 50 acres of
roadway pavements and roofs of houses. For a storm intensity of 2 inches per hour,
estimate the peak rate of runoff from the watershed.
A
n exfiltration test is conducted on a 300 ft long, 24 in. diameter sewer reach. If the
maximum allowable rate of exfiltration is specified to be 500 gal/day/inch/mile, what
would be the acceptable drop in the water level, in one hour, in a 4 ft diamete
r
manhole?
A 300 ml volume of water contains 0.006 mg of THM. Express the
concentration of THM in terms of ppb.
55
A
0.5 ppm concentration of copper sulfate is to be applied to a lake to control the
growth of algae. The lake volume is 50 ac-ft. How many pounds of copper sulfate
should be dissolved in the lake?
The limit on increase in water temperature in a stream is 20
∞
C according
to state standards. The low flow of the stream is 200 cfs when the temperature is
22∞C. Compute the maximum allowable temperature of 7.5 cfs of power plant
cooling water that can be discharged into the stream.
Compute the BOD5 of a domestic wastewater (k = 0.12) based on the
following data: volume of wastewater added to a 300 mL BOD bottle = 5.0 mL, initial
DO = 9.2 mg/L, and DO after 5 days of incubation = 4.3 mg/L. Also, compute the 10-
day BOD and the ultimate BOD.
Compute the pressure drop, in psi, through one mile of an 8 in. diameter pipe that
carries 1.6 cfs of water. Assume Hazen-Williams C = 100.
Solution:
56
What diameter pipe is needed to carry 5 ML/day of water, with a pressure drop not
exceeding 200 kPa/km?
What is the maximum population that can be served by a 900 mm diameter main
sewer constructed on minimum grade? If sewage flow in the pipe never exceeds a
depth of 600 mm, estimate the actual population contributing flow to the main.
A 300 mm diameter standard strength VCP is placed in a trench that is 0.9 meters
wide and 6 meters deep. The backfill is sand and gravel with a density of 18.6
kN/cubic meter. Determine the class of bedding needed if the factor of safety is 1.2
A
chlorine dosage of 3 mg/L is used to disinfect an average flow of 4 mgd. How
many 100 Ib chlorine cylinders are needed per month?
57
A
25 mgd domestic wastewater discharge has a concentration of 28 ppm o
f
ammonia nitrogen. If the receiving stream contains 2 mg/L of ammonia nitrogen,
and the maximum allowable concentration in the stream is 3.5 mg/L, compute the
minimum streamflow required.
Assuming a maximum overflow rate of 12 m3/m2d and a minimum detention time o
f
4 hours, what diameter circular clarifier and what side water depth are needed to
process a 12 ML/d flow rate?
3
The overflow rate for a settling tank is 1 gpm/ft2. If the side water depth is 10ft, what
is the detention time?
Construction specs for a wastewater collection system allow a maximum infiltration
rate of 400 gal/inch/mile/day. Compute the allowable infiltration in 3 miles of 20 in.
diameter pipe, and compare it to the minimum capacity of the pipe.
58
A wastewater sample has an ultimate BOD of 320 mg/L. A 5 mL volume of the
wastewater is diluted to 300 mL in a BOD bottle, and the initial DO is found to be
10.0 mg/L What would be the DO in the bottle after 5 days of incubation, assuming
k = 0.1/day?
From Eq. 4-2, BOD5 = 320 x (1 – 10 -0.12 x 5) = 240 mg/L
From Eq. 4-3, 240 = (10 – DO5) x 300/5, and DO5 = 6 mg/L
The 5-day BOD of an effluent from a poorly operating sewage treatment plant is 75
mg/L. (a) If the influent raw sewage 5-day BOD is 210 mg/L, at what efficiency is
the plant operating? (b) If the effluent flow rate is 1 ML/d, and the receiving stream
has a 5-day BOD of 3 mg/L, what minimum streamflow is needed for dilution, so
that the. combined 5-day BOD in the polluted stream does not exceed 10 mg/L?
A time interval of 1.5 hours is recorded for a 6 inch drop of water level in a perc test
hole. What is the perc rate? How many laterals would be required in the leaching
field to serve a 5 bedroom house, if the trench width is 2 feet and the maximum
trench length is 80 feet?
59
Catchment area 1 has an inlet time of 10 minutes and area 2 has an inlet time of
12 minutes. The average runoff coefficient for area 1 is 0.2, and for area 2 it is 0.7.
For a 5 year storm, determine the maximum runoff at inlet 1, the required pipe
diameter between inlets 1 and 2 for full flow conditions, and the peak rate of
runoff, Q, at inlet 2.
Solution:
60
