Wastewater Operator Exam TN QUESTIONS
WITH CORRECT SOLVED ANSWERS.
________ is added to enclosed spaces where biogas could accumulate to reduce the risk of a fire or
explosion - CORRECT ANSWER✅✅✅Nitrogen
________ should slowly be reduced for weeks ahead of time when planning to take an anaerobic
digester offline. - CORRECT ANSWER✅✅✅Volatile solids loading
_________ are used to promote the transfer of DO into the liquid - CORRECT
ANSWER✅✅✅Mechanical aerators
_________ does not occur within a rotary lobe blower, but instead occurs at the blower discharge -
CORRECT ANSWER✅✅✅Air compression
_________ studies are conducted by placing a precise amount of inert, detectable material in the
digester to determine mixing system performance - CORRECT ANSWER✅✅✅Tracer
__________ can increase HRT and improve VSR - CORRECT ANSWER✅✅✅Cleaning the digester
__________ is a blower condition where all discharge airflow rate is very high and the discharge
pressure is very low - CORRECT ANSWER✅✅✅Choke
__________ valves are the most commonly used valves for air isolation and control - CORRECT
ANSWER✅✅✅Butterfly
___________ bearings create a pressurized "air cushion" from the rotational velocity of the shaft within
the bearing - CORRECT ANSWER✅✅✅Air foil
,___________ blowers are commonly used at WWTPs - CORRECT ANSWER✅✅✅Centrifugal and
positive displacement
___________ blowers produce a fairly wide range of airflow rates over range of slightly different
pressure conditions - CORRECT ANSWER✅✅✅Centrifugal
___________ can occur when blower inlet air filters allow too many particles to pass through - CORRECT
ANSWER✅✅✅Air side diffuser fouling
___________ motors are often used with turbo blowers in order to meet the blower speed
requirements to provide improved efficiency - CORRECT ANSWER✅✅✅Permanent magnet
____________ are commonly used to connect straight line shafts of multistage centrifugal blowers and
their motors - CORRECT ANSWER✅✅✅Flexible couplings
____________ digester tanks become more favorable on digester projects where a facility has extra land
area available and the construction budget is limited - CORRECT ANSWER✅✅✅Pancake
_____________ is a frequent mini cleaning technique where high air flows are sent through membrane
diffusers are short periods of time - CORRECT ANSWER✅✅✅Air bumping
______________ blowers produce fairly constant airflow rates over a range of different pressure
conditions - CORRECT ANSWER✅✅✅Positive displacement
______________ is when low pressure air is injected below the water surface in a process tank in order
to transfer DO into the liquid - CORRECT ANSWER✅✅✅Diffused aeration
_______________ provides early indication that an inlet air filter is becoming plugged before blower
performance is negatively impacted - CORRECT ANSWER✅✅✅A differential pressure sensor
,_______________ takes into account the total cost of ownership of an piece of equipment, which can
be factored into the decision of whether or not to purchase equipment - CORRECT
ANSWER✅✅✅Life-cycle cost analysis
_________________ are both types of positive displacement blowers. - CORRECT
ANSWER✅✅✅Rotary lobe and rotary screw
A __________ converts incoming power to an adjustable frequency that can be used to control the
speed of the piece of equipment that it is powering - CORRECT ANSWER✅✅✅VFD
A ____________ is required at every point where a load must be carried between a stationary and
moving part - CORRECT ANSWER✅✅✅Bearing
A 1 ton chlorine container has this many fusible plugs - CORRECT ANSWER✅✅✅6 plugs
A benefit of using an ESD is - CORRECT ANSWER✅✅✅good mixing characteristics
A common limiting factor for bacterial growth in a secondary treatment process is: - CORRECT
ANSWER✅✅✅Accumulation of toxic byproducts
A conventional activated sludge system that performs only BOD removal typically has an F/M in the
range of : - CORRECT ANSWER✅✅✅0.20-0.40
A digester receiving both primary and secondary sludge will - CORRECT ANSWER✅✅✅Consume
more oxygen than a digester receiving only secondary sludge
A domestic WWTP receives the majority of its wastewater from a fruit process and canning factory. The
WWTP has an ongoing issue with slimy, viscous, gray foam, to fix the problem they need to: - CORRECT
ANSWER✅✅✅Add missing nutrients
A facultative pond has a pH of 8.5 and an abundance of green algae. The HDT is less than 10 days. The
influent ammonia concentration is 25 mg/L and the final effluent concentration is 8 mg/L. What is the
, primary method of ammonia removal under these operating conditions - CORRECT
ANSWER✅✅✅Volatizarían to atmosphere
A facultative pond turns dark purple what is the likely cause? - CORRECT ANSWER✅✅✅Anaerobic
conditions have caused a bloom of purple sulfur bacteria
A few days after high flow conditions, and high organic loading to the plant, and with the chlorination
equipment set at the correct feed rate, the effluent chlorine residual is too low and the fecal coliflor
count int he effluent is too high. What is the probably cuase? - CORRECT ANSWER✅✅✅Solids
accumulation in the chlorine contact chamber
A fixed film process receives a heavy organic load what will happen now? - CORRECT
ANSWER✅✅✅Heterotrophic bacteria will overgrow the nitrifying bacteria
A gas cylinder valve should only be opened ____ turn so it can be closed quickly in an emergency -
CORRECT ANSWER✅✅✅One quarter
A gradual decline in the heat transfer rate in a digester heating system is - CORRECT ANSWER✅✅✅A
fouled heat exchanger
A grit basin has flow velocity of 1ft/sec at 9AM as flows increase throughout the day grit basin
performance will: - CORRECT ANSWER✅✅✅Decrease
A healthy pond with high DO should appear - CORRECT ANSWER✅✅✅Green and sparkling
A heterotrophic bacterium is placed under anoxic conditions this bacterium will - CORRECT
ANSWER✅✅✅Convert CBOD to N2CO and H20 using nitrate
A high sewage pH can result int production of toxic gases due to : - CORRECT
ANSWER✅✅✅Ammonia
WITH CORRECT SOLVED ANSWERS.
________ is added to enclosed spaces where biogas could accumulate to reduce the risk of a fire or
explosion - CORRECT ANSWER✅✅✅Nitrogen
________ should slowly be reduced for weeks ahead of time when planning to take an anaerobic
digester offline. - CORRECT ANSWER✅✅✅Volatile solids loading
_________ are used to promote the transfer of DO into the liquid - CORRECT
ANSWER✅✅✅Mechanical aerators
_________ does not occur within a rotary lobe blower, but instead occurs at the blower discharge -
CORRECT ANSWER✅✅✅Air compression
_________ studies are conducted by placing a precise amount of inert, detectable material in the
digester to determine mixing system performance - CORRECT ANSWER✅✅✅Tracer
__________ can increase HRT and improve VSR - CORRECT ANSWER✅✅✅Cleaning the digester
__________ is a blower condition where all discharge airflow rate is very high and the discharge
pressure is very low - CORRECT ANSWER✅✅✅Choke
__________ valves are the most commonly used valves for air isolation and control - CORRECT
ANSWER✅✅✅Butterfly
___________ bearings create a pressurized "air cushion" from the rotational velocity of the shaft within
the bearing - CORRECT ANSWER✅✅✅Air foil
,___________ blowers are commonly used at WWTPs - CORRECT ANSWER✅✅✅Centrifugal and
positive displacement
___________ blowers produce a fairly wide range of airflow rates over range of slightly different
pressure conditions - CORRECT ANSWER✅✅✅Centrifugal
___________ can occur when blower inlet air filters allow too many particles to pass through - CORRECT
ANSWER✅✅✅Air side diffuser fouling
___________ motors are often used with turbo blowers in order to meet the blower speed
requirements to provide improved efficiency - CORRECT ANSWER✅✅✅Permanent magnet
____________ are commonly used to connect straight line shafts of multistage centrifugal blowers and
their motors - CORRECT ANSWER✅✅✅Flexible couplings
____________ digester tanks become more favorable on digester projects where a facility has extra land
area available and the construction budget is limited - CORRECT ANSWER✅✅✅Pancake
_____________ is a frequent mini cleaning technique where high air flows are sent through membrane
diffusers are short periods of time - CORRECT ANSWER✅✅✅Air bumping
______________ blowers produce fairly constant airflow rates over a range of different pressure
conditions - CORRECT ANSWER✅✅✅Positive displacement
______________ is when low pressure air is injected below the water surface in a process tank in order
to transfer DO into the liquid - CORRECT ANSWER✅✅✅Diffused aeration
_______________ provides early indication that an inlet air filter is becoming plugged before blower
performance is negatively impacted - CORRECT ANSWER✅✅✅A differential pressure sensor
,_______________ takes into account the total cost of ownership of an piece of equipment, which can
be factored into the decision of whether or not to purchase equipment - CORRECT
ANSWER✅✅✅Life-cycle cost analysis
_________________ are both types of positive displacement blowers. - CORRECT
ANSWER✅✅✅Rotary lobe and rotary screw
A __________ converts incoming power to an adjustable frequency that can be used to control the
speed of the piece of equipment that it is powering - CORRECT ANSWER✅✅✅VFD
A ____________ is required at every point where a load must be carried between a stationary and
moving part - CORRECT ANSWER✅✅✅Bearing
A 1 ton chlorine container has this many fusible plugs - CORRECT ANSWER✅✅✅6 plugs
A benefit of using an ESD is - CORRECT ANSWER✅✅✅good mixing characteristics
A common limiting factor for bacterial growth in a secondary treatment process is: - CORRECT
ANSWER✅✅✅Accumulation of toxic byproducts
A conventional activated sludge system that performs only BOD removal typically has an F/M in the
range of : - CORRECT ANSWER✅✅✅0.20-0.40
A digester receiving both primary and secondary sludge will - CORRECT ANSWER✅✅✅Consume
more oxygen than a digester receiving only secondary sludge
A domestic WWTP receives the majority of its wastewater from a fruit process and canning factory. The
WWTP has an ongoing issue with slimy, viscous, gray foam, to fix the problem they need to: - CORRECT
ANSWER✅✅✅Add missing nutrients
A facultative pond has a pH of 8.5 and an abundance of green algae. The HDT is less than 10 days. The
influent ammonia concentration is 25 mg/L and the final effluent concentration is 8 mg/L. What is the
, primary method of ammonia removal under these operating conditions - CORRECT
ANSWER✅✅✅Volatizarían to atmosphere
A facultative pond turns dark purple what is the likely cause? - CORRECT ANSWER✅✅✅Anaerobic
conditions have caused a bloom of purple sulfur bacteria
A few days after high flow conditions, and high organic loading to the plant, and with the chlorination
equipment set at the correct feed rate, the effluent chlorine residual is too low and the fecal coliflor
count int he effluent is too high. What is the probably cuase? - CORRECT ANSWER✅✅✅Solids
accumulation in the chlorine contact chamber
A fixed film process receives a heavy organic load what will happen now? - CORRECT
ANSWER✅✅✅Heterotrophic bacteria will overgrow the nitrifying bacteria
A gas cylinder valve should only be opened ____ turn so it can be closed quickly in an emergency -
CORRECT ANSWER✅✅✅One quarter
A gradual decline in the heat transfer rate in a digester heating system is - CORRECT ANSWER✅✅✅A
fouled heat exchanger
A grit basin has flow velocity of 1ft/sec at 9AM as flows increase throughout the day grit basin
performance will: - CORRECT ANSWER✅✅✅Decrease
A healthy pond with high DO should appear - CORRECT ANSWER✅✅✅Green and sparkling
A heterotrophic bacterium is placed under anoxic conditions this bacterium will - CORRECT
ANSWER✅✅✅Convert CBOD to N2CO and H20 using nitrate
A high sewage pH can result int production of toxic gases due to : - CORRECT
ANSWER✅✅✅Ammonia
