Chlorination is one of the oldest and least effective False- it is one of the oldest & most effective
methods of controlling odors.
T or F
The reaction of chlorine with certain chemicals can cause True
a more odorous gas.
T or F
Decreasing the pH of wastewater is an effective odor False- Increasing is an effective method
control method for hydrogen sulfide.
T or F
Odor control towers must have a biomass established on True
the filter media in order to remove odors.
T or F
The hazard classification of the spent carbon from odor True
control must be established when considering disposal.
T or F
Regeneration of activated carbon temporarily eliminates True
any concerns about hazardous waste disposal.
T or F
Hydrogen sulfide gas combines with moisture to form True
sulfuric acid, which is very corrosive.
T or F
Which factor causes increased odor and corrosion Increased travel times for wastewater to reach treatment plants
problems in wastewater treatment plants?
What is the principle source of odor generation in Production of inorganic and organic gases by microorganisms
wastewater collection systems and treatment processes?
What is the main cause of most odors in wastewater Hydrogen sulfide
systems?
What is the most common source of sulfide in Biological activity in the collection sewer or treatment plant
wastewater?
,Why is the temperature of the wastewater system an The rate of bacterial metabolism is related to temperature
important factor in the production of hydrogen sulfide
gas?
Why does ozone have limited use in controlling odors? Because an effective concentration may be too costly to use at large treatment
plants
What is the problem with using combustion to remove The combustibility of the gases is so low that fuel costs are high
odors from wastewater treatment plant gases?
How can cathode scale be removed from an electrolytic Flush the system with dilute nitric acid
chemical scrubber unit?
What is the adsorption odor removal process? The Adherence to a solid surface
process in which odorous components are removed from
a a gas through
What is the best solution to odor problems? Prevent odors from ever developing
How are odors generated in wastewater collection -Biological generation
systems and treatment plants? -Hydrogen sulfide generation
-Hydrogen transfer schemes
Which problems are created by hydrogen sulfide gas? -corrosion or deterioration of concrete sewer structures
-explosive gas mixtures
-hazards to the respiratory system to persons working in confined or close spaces
-rotten egg odor
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
Investigations in the neighborhood near the location of -dead animal
an odor complaint may reveal that the odors are coming -home plumbing problem
from which possible nearby sources? -sewer
-storm drain
-trash pile
, Which items are possible solutions operators can use to -changing or enforcing sewer-use ordinances
control odors? -immediately removing floating scum/solids
-maintaining dissolved oxygen in the wastewater
-minimizing hydraulic detention times in pipes and wet wells
-routinely and frequently disposing of screenings and grit
How does chlorine control odors? -destroys bacteria that convert sulfate to sulfide
-destroys hydrogen sulfide at the point of application
-inhibits the growth of slime layers in sewers
How does hydrogen peroxide control odors? -by killing sulfate-reducing bacteria
-by oxidant action
-by producing oxygen
What are the advantages of using hydrogen peroxide to -ability to inhibit the regeneration of sulfate-reducing microorganisms
control odors? -effectiveness as an oxidant
-lack of toxic by-products
Which odorous gases can be removed by absorption by -ammonia
a hypochlorite process? -hydrogen sulfide
-mercaptans
-organic gases
-sulfur dioxide
To ensure optimal odor removal efficiency of a chemical -check chemical feed pumps
mist odor control system, which tasks should be -check chemical tank levels
performed daily? -check outlet hydrogen sulfide concentration
-check water flow rate and pressure
Which safety precautions should be taken when working -provide an emergency eye wash/deluge shower in an easily accessible location
with or installing a chemical mist odor control system? near the installation
-provide secondary containment for the chemical storage tanks
-routinely inspect the system for leaks
-use proper lockout/blockout procedures when working on equipment
-wear PPE when handling process chemicals
What are the advantages of using activated carbon -ability to increase adsorbent capability by the use of additive compounds
adsorption to control odors? -accommodation of high gas flow rates by the use of multiple units
-fairly consistent reliability
-simple operation
methods of controlling odors.
T or F
The reaction of chlorine with certain chemicals can cause True
a more odorous gas.
T or F
Decreasing the pH of wastewater is an effective odor False- Increasing is an effective method
control method for hydrogen sulfide.
T or F
Odor control towers must have a biomass established on True
the filter media in order to remove odors.
T or F
The hazard classification of the spent carbon from odor True
control must be established when considering disposal.
T or F
Regeneration of activated carbon temporarily eliminates True
any concerns about hazardous waste disposal.
T or F
Hydrogen sulfide gas combines with moisture to form True
sulfuric acid, which is very corrosive.
T or F
Which factor causes increased odor and corrosion Increased travel times for wastewater to reach treatment plants
problems in wastewater treatment plants?
What is the principle source of odor generation in Production of inorganic and organic gases by microorganisms
wastewater collection systems and treatment processes?
What is the main cause of most odors in wastewater Hydrogen sulfide
systems?
What is the most common source of sulfide in Biological activity in the collection sewer or treatment plant
wastewater?
,Why is the temperature of the wastewater system an The rate of bacterial metabolism is related to temperature
important factor in the production of hydrogen sulfide
gas?
Why does ozone have limited use in controlling odors? Because an effective concentration may be too costly to use at large treatment
plants
What is the problem with using combustion to remove The combustibility of the gases is so low that fuel costs are high
odors from wastewater treatment plant gases?
How can cathode scale be removed from an electrolytic Flush the system with dilute nitric acid
chemical scrubber unit?
What is the adsorption odor removal process? The Adherence to a solid surface
process in which odorous components are removed from
a a gas through
What is the best solution to odor problems? Prevent odors from ever developing
How are odors generated in wastewater collection -Biological generation
systems and treatment plants? -Hydrogen sulfide generation
-Hydrogen transfer schemes
Which problems are created by hydrogen sulfide gas? -corrosion or deterioration of concrete sewer structures
-explosive gas mixtures
-hazards to the respiratory system to persons working in confined or close spaces
-rotten egg odor
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
Investigations in the neighborhood near the location of -dead animal
an odor complaint may reveal that the odors are coming -home plumbing problem
from which possible nearby sources? -sewer
-storm drain
-trash pile
, Which items are possible solutions operators can use to -changing or enforcing sewer-use ordinances
control odors? -immediately removing floating scum/solids
-maintaining dissolved oxygen in the wastewater
-minimizing hydraulic detention times in pipes and wet wells
-routinely and frequently disposing of screenings and grit
How does chlorine control odors? -destroys bacteria that convert sulfate to sulfide
-destroys hydrogen sulfide at the point of application
-inhibits the growth of slime layers in sewers
How does hydrogen peroxide control odors? -by killing sulfate-reducing bacteria
-by oxidant action
-by producing oxygen
What are the advantages of using hydrogen peroxide to -ability to inhibit the regeneration of sulfate-reducing microorganisms
control odors? -effectiveness as an oxidant
-lack of toxic by-products
Which odorous gases can be removed by absorption by -ammonia
a hypochlorite process? -hydrogen sulfide
-mercaptans
-organic gases
-sulfur dioxide
To ensure optimal odor removal efficiency of a chemical -check chemical feed pumps
mist odor control system, which tasks should be -check chemical tank levels
performed daily? -check outlet hydrogen sulfide concentration
-check water flow rate and pressure
Which safety precautions should be taken when working -provide an emergency eye wash/deluge shower in an easily accessible location
with or installing a chemical mist odor control system? near the installation
-provide secondary containment for the chemical storage tanks
-routinely inspect the system for leaks
-use proper lockout/blockout procedures when working on equipment
-wear PPE when handling process chemicals
What are the advantages of using activated carbon -ability to increase adsorbent capability by the use of additive compounds
adsorption to control odors? -accommodation of high gas flow rates by the use of multiple units
-fairly consistent reliability
-simple operation
