CLASS B WASTEWATER EXAM WITH VERIFIED ANSWERS
1.If wastewater contains dissolved oxygen, the biological breakdown
will reduce sulfate to sulfide.
T or F: False
2.At a pH below 5, all sulfide is present in the gaseous h2s form and most
of it can be released from wastewater.
T or F: True
3.In order to control odors effectively, the operator should know where
odors originate and the cause.
T or F: True
4.Chlorination is one of the oldest and least effective methods of
controlling odors.
T or F: False- it is one of the oldest & most effective
5.The reaction of chlorine with certain chemicals can cause a more
odorous gas.
T or F: True
6.Decreasing the pH of wastewater is an effective odor control method
for hydrogen sulfide.
T or F: False- Increasing is an effective method
7.Odor control towers must have a biomass established on the filter media
in order to remove odors.
,T or F: True
8.The hazard classification of the spent carbon from odor control must
be established when considering disposal.
T or F: True
9.Regeneration of activated carbon temporarily eliminates any
concerns about hazardous waste disposal.
T or F: True
10.Hydrogen sulfide gas combines with moisture to form sulfuric acid,
which is very corrosive.
T or F: True
11. Which factor causes increased odor and corrosion problems in
wastewater treatment plants?: Increased travel times for wastewater to
reach treatment plants
12.What is the principle source of odor generation in wastewater collection
systems and treatment processes?: Production of inorganic and organic
gases by microorganisms
13.What is the main cause of most odors in wastewater systems?:
Hydrogen sulfide
14.What is the most common source of sulfide in wastewater?:
Biological activity in the collection sewer or treatment plant
,15.Why is the temperature of the wastewater system an important factor in
the production of hydrogen sulfide gas?: The rate of bacterial metabolism
is related to temperature
16.Why does ozone have limited use in controlling odors?: Because an
effec- tive concentration may be too costly to use at large treatment
plants
17.What is the problem with using combustion to remove odors from
waste- water treatment plant gases?: The combustibility of the gases is so
low that fuel costs are high
18.How can cathode scale be removed from an electrolytic chemical
scrubber unit?: Flush the system with dilute nitric acid
19.What is the adsorption odor removal process? The process in which
odorous components are removed from a a gas through: Adherence to a
solid surface
20.What is the best solution to odor problems?: Prevent odors from ever
devel- oping
21.How are odors generated in wastewater collection systems and
treatment plants?: -Biological generation
-Hydrogen sulfide generation
-Hydrogen transfer schemes
22.Which problems are created by hydrogen sulfide gas?: -corrosion or
deteri- oration of concrete sewer structures
-explosive gas mixtures
-hazards to the respiratory system to persons working in confined or
close spaces
-rotten egg odor
23.Which items are facts that can help in odor classification?: -
individuals respond differently to the same odor
-odors travel great distances with the direction of the wind
-small concentrations of odors can be offensive
-some odors are objectionable and others are pleasant
-the human nose rapidly becomes fatigued (insensitive) to odors
24.Investigations in the neighborhood near the location of an odor
complaint may reveal that the odors are coming from which possible nearby
sources?-
: -dead animal
-home plumbing problem
-sewer
-storm drain
, -trash pile
25.Which items are possible solutions operators can use to control odors?:
-changing or enforcing sewer-use ordinances
1.If wastewater contains dissolved oxygen, the biological breakdown
will reduce sulfate to sulfide.
T or F: False
2.At a pH below 5, all sulfide is present in the gaseous h2s form and most
of it can be released from wastewater.
T or F: True
3.In order to control odors effectively, the operator should know where
odors originate and the cause.
T or F: True
4.Chlorination is one of the oldest and least effective methods of
controlling odors.
T or F: False- it is one of the oldest & most effective
5.The reaction of chlorine with certain chemicals can cause a more
odorous gas.
T or F: True
6.Decreasing the pH of wastewater is an effective odor control method
for hydrogen sulfide.
T or F: False- Increasing is an effective method
7.Odor control towers must have a biomass established on the filter media
in order to remove odors.
,T or F: True
8.The hazard classification of the spent carbon from odor control must
be established when considering disposal.
T or F: True
9.Regeneration of activated carbon temporarily eliminates any
concerns about hazardous waste disposal.
T or F: True
10.Hydrogen sulfide gas combines with moisture to form sulfuric acid,
which is very corrosive.
T or F: True
11. Which factor causes increased odor and corrosion problems in
wastewater treatment plants?: Increased travel times for wastewater to
reach treatment plants
12.What is the principle source of odor generation in wastewater collection
systems and treatment processes?: Production of inorganic and organic
gases by microorganisms
13.What is the main cause of most odors in wastewater systems?:
Hydrogen sulfide
14.What is the most common source of sulfide in wastewater?:
Biological activity in the collection sewer or treatment plant
,15.Why is the temperature of the wastewater system an important factor in
the production of hydrogen sulfide gas?: The rate of bacterial metabolism
is related to temperature
16.Why does ozone have limited use in controlling odors?: Because an
effec- tive concentration may be too costly to use at large treatment
plants
17.What is the problem with using combustion to remove odors from
waste- water treatment plant gases?: The combustibility of the gases is so
low that fuel costs are high
18.How can cathode scale be removed from an electrolytic chemical
scrubber unit?: Flush the system with dilute nitric acid
19.What is the adsorption odor removal process? The process in which
odorous components are removed from a a gas through: Adherence to a
solid surface
20.What is the best solution to odor problems?: Prevent odors from ever
devel- oping
21.How are odors generated in wastewater collection systems and
treatment plants?: -Biological generation
-Hydrogen sulfide generation
-Hydrogen transfer schemes
22.Which problems are created by hydrogen sulfide gas?: -corrosion or
deteri- oration of concrete sewer structures
-explosive gas mixtures
-hazards to the respiratory system to persons working in confined or
close spaces
-rotten egg odor
23.Which items are facts that can help in odor classification?: -
individuals respond differently to the same odor
-odors travel great distances with the direction of the wind
-small concentrations of odors can be offensive
-some odors are objectionable and others are pleasant
-the human nose rapidly becomes fatigued (insensitive) to odors
24.Investigations in the neighborhood near the location of an odor
complaint may reveal that the odors are coming from which possible nearby
sources?-
: -dead animal
-home plumbing problem
-sewer
-storm drain
, -trash pile
25.Which items are possible solutions operators can use to control odors?:
-changing or enforcing sewer-use ordinances
