ICC General Requirements Practice Exam Questions
With Complete Solutions
Course
ICC
Question 71
What type of biological treatment involves using microorganisms to treat wastewater in a
continuous flow system? A) Batch treatment
B) Aerated lagoons
C) Sequencing batch reactor
D) Activated sludge process
Answer: D) Activated sludge process
Rationale: The activated sludge process is a continuous flow system that uses
microorganisms to digest organic material in wastewater, allowing for effective treatment.
Question 72
What does the term "denitrification" refer to in wastewater treatment? A) The removal of
phosphorus from wastewater
B) The conversion of nitrates to nitrogen gas
C) The reduction of suspended solids
D) The increase of dissolved oxygen levels
Answer: B) The conversion of nitrates to nitrogen gas
Rationale: Denitrification is a biological process where nitrates are converted into nitrogen
gas, which is released into the atmosphere, reducing nitrogen levels in wastewater.
Question 73
Which type of sludge is most commonly used in aerobic digestion processes? A) Primary
sludge
B) Secondary sludge
C) Tertiary sludge
D) Stabilized sludge
Answer: B) Secondary sludge
Rationale: Secondary sludge, which is rich in microorganisms, is typically used in aerobic
digestion processes to further stabilize organic material and reduce volume.
Question 74
,What is the typical retention time in an aerobic digester? A) 1-3 days
B) 5-10 days
C) 15-30 days
D) 30-60 days
Answer: C) 15-30 days
Rationale: Aerobic digesters usually operate with a retention time of 15 to 30 days to allow
sufficient time for the microbial population to stabilize and digest the organic material.
Question 75
What type of filtration removes particles based on size, typically utilizing membranes? A)
Gravity filtration
B) Microfiltration
C) Sand filtration
D) Cloth filtration
Answer: B) Microfiltration
Rationale: Microfiltration uses membranes with small pore sizes to separate suspended
solids and microorganisms from liquids, making it effective for wastewater treatment.
Question 76
Which component is responsible for the removal of dissolved gases from wastewater? A) Grit
chamber
B) Aeration tank
C) Equalization tank
D) Degasifier
Answer: D) Degasifier
Rationale: A degasifier is specifically designed to remove dissolved gases, such as carbon
dioxide and methane, from wastewater prior to treatment.
Question 77
What is the most common cause of foaming in activated sludge systems? A) High pH levels
B) Low dissolved oxygen
C) Presence of surfactants
D) Excessive organic loading
Answer: C) Presence of surfactants
Rationale: Foaming in activated sludge systems is often caused by the presence of
surfactants, which can stabilize air bubbles and lead to excessive foam formation.
,Question 78
Which method is often employed to achieve disinfection in wastewater treatment? A)
Sedimentation
B) Ultraviolet (UV) light
C) Biological treatment
D) Filtration
Answer: B) Ultraviolet (UV) light
Rationale: Ultraviolet (UV) disinfection is a widely used method that effectively inactivates
pathogens in wastewater without adding chemicals.
Question 79
What is the purpose of the sludge thickener in wastewater treatment? A) To aerate sludge
B) To increase the solids concentration
C) To reduce odors
D) To facilitate disinfection
Answer: B) To increase the solids concentration
Rationale: A sludge thickener is used to concentrate solids by reducing the volume of water,
which enhances the efficiency of subsequent treatment processes.
Question 80
Which of the following is an indicator of a well-functioning wastewater treatment process?
A) High total suspended solids (TSS)
B) Low biochemical oxygen demand (BOD)
C) High chemical oxygen demand (COD)
D) Elevated coliform levels
Answer: B) Low biochemical oxygen demand (BOD)
Rationale: A low BOD indicates that the wastewater treatment process is effectively
reducing organic matter, which is essential for protecting water quality.
Question 81
What is the primary objective of primary treatment in wastewater treatment? A) Nutrient
removal
B) Solids removal
, C) Disinfection
D) Odor control
Answer: B) Solids removal
Rationale: Primary treatment focuses on the physical removal of large solids and suspended
particles from wastewater, primarily through sedimentation.
Question 82
What does "recarbonation" refer to in wastewater treatment? A) The removal of carbon
dioxide
B) The addition of carbonates to adjust pH
C) The reduction of volatile solids
D) The stabilization of sludge
Answer: B) The addition of carbonates to adjust pH
Rationale: Recabonation is the process of adding carbonates to wastewater to neutralize
acidity and improve the pH balance for further treatment.
Question 83
What is the main purpose of a sand filter in wastewater treatment? A) To remove nutrients
B) To provide biological treatment
C) To remove suspended solids
D) To disinfect effluent
Answer: C) To remove suspended solids
Rationale: Sand filters are used to physically remove suspended solids from wastewater,
enhancing treatment efficiency.
Question 84
What is the effect of temperature on biochemical processes in wastewater treatment? A) No
effect on process efficiency
B) Increased efficiency at all temperatures
C) Higher temperatures can enhance microbial activity
D) Low temperatures speed up biological reactions
Answer: C) Higher temperatures can enhance microbial activity
Rationale: Higher temperatures generally increase microbial metabolism, improving the
efficiency of biological treatment processes up to an optimal point.
With Complete Solutions
Course
ICC
Question 71
What type of biological treatment involves using microorganisms to treat wastewater in a
continuous flow system? A) Batch treatment
B) Aerated lagoons
C) Sequencing batch reactor
D) Activated sludge process
Answer: D) Activated sludge process
Rationale: The activated sludge process is a continuous flow system that uses
microorganisms to digest organic material in wastewater, allowing for effective treatment.
Question 72
What does the term "denitrification" refer to in wastewater treatment? A) The removal of
phosphorus from wastewater
B) The conversion of nitrates to nitrogen gas
C) The reduction of suspended solids
D) The increase of dissolved oxygen levels
Answer: B) The conversion of nitrates to nitrogen gas
Rationale: Denitrification is a biological process where nitrates are converted into nitrogen
gas, which is released into the atmosphere, reducing nitrogen levels in wastewater.
Question 73
Which type of sludge is most commonly used in aerobic digestion processes? A) Primary
sludge
B) Secondary sludge
C) Tertiary sludge
D) Stabilized sludge
Answer: B) Secondary sludge
Rationale: Secondary sludge, which is rich in microorganisms, is typically used in aerobic
digestion processes to further stabilize organic material and reduce volume.
Question 74
,What is the typical retention time in an aerobic digester? A) 1-3 days
B) 5-10 days
C) 15-30 days
D) 30-60 days
Answer: C) 15-30 days
Rationale: Aerobic digesters usually operate with a retention time of 15 to 30 days to allow
sufficient time for the microbial population to stabilize and digest the organic material.
Question 75
What type of filtration removes particles based on size, typically utilizing membranes? A)
Gravity filtration
B) Microfiltration
C) Sand filtration
D) Cloth filtration
Answer: B) Microfiltration
Rationale: Microfiltration uses membranes with small pore sizes to separate suspended
solids and microorganisms from liquids, making it effective for wastewater treatment.
Question 76
Which component is responsible for the removal of dissolved gases from wastewater? A) Grit
chamber
B) Aeration tank
C) Equalization tank
D) Degasifier
Answer: D) Degasifier
Rationale: A degasifier is specifically designed to remove dissolved gases, such as carbon
dioxide and methane, from wastewater prior to treatment.
Question 77
What is the most common cause of foaming in activated sludge systems? A) High pH levels
B) Low dissolved oxygen
C) Presence of surfactants
D) Excessive organic loading
Answer: C) Presence of surfactants
Rationale: Foaming in activated sludge systems is often caused by the presence of
surfactants, which can stabilize air bubbles and lead to excessive foam formation.
,Question 78
Which method is often employed to achieve disinfection in wastewater treatment? A)
Sedimentation
B) Ultraviolet (UV) light
C) Biological treatment
D) Filtration
Answer: B) Ultraviolet (UV) light
Rationale: Ultraviolet (UV) disinfection is a widely used method that effectively inactivates
pathogens in wastewater without adding chemicals.
Question 79
What is the purpose of the sludge thickener in wastewater treatment? A) To aerate sludge
B) To increase the solids concentration
C) To reduce odors
D) To facilitate disinfection
Answer: B) To increase the solids concentration
Rationale: A sludge thickener is used to concentrate solids by reducing the volume of water,
which enhances the efficiency of subsequent treatment processes.
Question 80
Which of the following is an indicator of a well-functioning wastewater treatment process?
A) High total suspended solids (TSS)
B) Low biochemical oxygen demand (BOD)
C) High chemical oxygen demand (COD)
D) Elevated coliform levels
Answer: B) Low biochemical oxygen demand (BOD)
Rationale: A low BOD indicates that the wastewater treatment process is effectively
reducing organic matter, which is essential for protecting water quality.
Question 81
What is the primary objective of primary treatment in wastewater treatment? A) Nutrient
removal
B) Solids removal
, C) Disinfection
D) Odor control
Answer: B) Solids removal
Rationale: Primary treatment focuses on the physical removal of large solids and suspended
particles from wastewater, primarily through sedimentation.
Question 82
What does "recarbonation" refer to in wastewater treatment? A) The removal of carbon
dioxide
B) The addition of carbonates to adjust pH
C) The reduction of volatile solids
D) The stabilization of sludge
Answer: B) The addition of carbonates to adjust pH
Rationale: Recabonation is the process of adding carbonates to wastewater to neutralize
acidity and improve the pH balance for further treatment.
Question 83
What is the main purpose of a sand filter in wastewater treatment? A) To remove nutrients
B) To provide biological treatment
C) To remove suspended solids
D) To disinfect effluent
Answer: C) To remove suspended solids
Rationale: Sand filters are used to physically remove suspended solids from wastewater,
enhancing treatment efficiency.
Question 84
What is the effect of temperature on biochemical processes in wastewater treatment? A) No
effect on process efficiency
B) Increased efficiency at all temperatures
C) Higher temperatures can enhance microbial activity
D) Low temperatures speed up biological reactions
Answer: C) Higher temperatures can enhance microbial activity
Rationale: Higher temperatures generally increase microbial metabolism, improving the
efficiency of biological treatment processes up to an optimal point.
