Colorado WW Operator D Exam ACTUAL EXAM
QUESTIONS WITH COMPLETE SOLUTION GUIDE (A+
GRADED 100% VERIFIED) LATEST VERSION 2025!!
Batch processes are used to treat metal wastes because they are: - - answer -;Simple, dependable,
regulated until the wastewater being treated receives satisfactory treatment, and they are easy to
control
Sulfide precipitation can achieve lower metals concentrations in the final effluent than hydroxide
precipitation. T/F? - - answer -;TRUE
For tertiary denitrification, this supplemental carbon source is often added. - - answer -;Methanol
Nitrogen and phosphorus must be removed from the effluent before farmers can irrigate with the
treated effluent. T/F? - - answer -;FALSE
What is the correct order of nitrification? - - answer -;Ammonium à Nitrite à Nitrate
The optimum pH for nitrification is between. - - answer -;9-Aug
Without mineral additions for phosphorus removal, the expected percent phosphorus removal in an
activated sludge system is - - answer -;10 - 30%
Nitrosomonas & Nitrobacter are ______ ______, needing oxygen to survive. - - answer -;Obligate
aerobes
,This is the primary reason for limiting nitrate concentrations in receiving waters. - - answer -;Drinking
water standard of 10 mg/L NO3-N
With respect to natural systems, this element is most often the one that limits the growth of algae and
other organisms. - - answer -;Phosphorus
Name the two nitrifying bacteria. - - answer -;Nitrosomonas and Nitrobacter
It is advantageous to denitrify following nitrification as nearly half of this may be recovered. - - answer -
;Alkalinity
Which is not a chemical used to precipitate phosphorus from a wastewater effluent? - - answer -;Sulfur
dioxide
In addition to oxygen, nitrifiers consume bicarbonate alkalinity and produce carbonic acid. T/F? - -
answer -;TRUE
Biological phosphorus conditioning occurs in what zone? - - answer -;Fermentation
Biological phosphorus removal requires the presence of this type of chamber just ahead of the aeration
basins. - - answer -;Anaerobic
Theoretically, ____lbs. of alkalinity is consumed per lb. of ammonia - - answer -;7.14
What happens when denitrification takes place in the clarifier blanket? - - answer -;Floating sludge /
Blanket Pops / Rising Sludge
The biomass of a conventional activated sludge process contains about 2% phosphorus on a dry weight
basis? T/F? - - answer -;TRUE
,This concentration of nitrite is typical for a wastewater treatment plant effluent. - - answer -;< 0.5 mg/L
NO2-N
The two technologies for biological phosphorus removal are _____ stream and _______ stream. - -
answer -;Main and side
Assuming good mixing conditions, where is the optimal chemical feed point for phosphorus removal
with minimal chemical sludge production? - - answer -;At or near the end of the biological treatment
All of these requirements must be met before denitrification can take place. - - answer -;Presence of
food (BOD), absence of oxygen, and presence of nitrate
Since nitrification is an acid generating process, it consumes __________. - - answer -;Alkalinity
While BOD removal requires 1.5 lbs of oxygen per lb of BOD, nitrification requires this many lbs per lb of
ammonia nitrogen. - - answer -;4.33
This common atmospheric gas is the end product of denitrification. - - answer -;Nitrogen gas
Oxygen deficiency becomes a concern when the oxygen level in a confined space is less than - - answer -
;19.50%
Forklift accidents are particularly dangerous because of - - answer -;The tremendous weight of the
forklift
Which of the following hazardous chemicals is a hydrocarbon? Phosphoric acid, sodium hydroxide,
methane, ferric chloride. - - answer -;Methane
When working in confined spaces where flammable gases may be present, use only tools made of ____.
- - answer -;A non-sparking alloy
When chlorine reacts with H2S gas, the H2S is - - answer -;Oxidized and made odorless
, If your 1 ton chlorine cylinder is leaking, what type of Chlorine Institute repair kit should be used? - -
answer -;B
Pulmonary capacity tests are required before operators can be cleared for using respiratory equipment.
These tests should be performed at a a minimum of once every...? - - answer -;3 years
What types of wastes generally are prohibited from discharge to wastewater treatment plants? - -
answer -;Corrosives with a pH lower than 5.0
According to Article 250 of the US National Electric Code (NEC), what color should ground wires be? - -
answer -;Green
In a confined space entry, the entry supervisor must ensure that all confined space entry permit
provisions have been fulfilled and certify the same by signing the permit. T/F? - - answer -;TRUE
"Flammable" liquids have a flash point _________ 100 degrees F. - - answer -;Below
If you need to raise your voice to be heard by someone less than 2 ft away, chances are you should be
wearing hearing protection. T/F? - - answer -;TRUE
When used to ventilate a manhole, a portable blower should be at least _____ ft away. - - answer -;7
Combustible gas detectors measure gases and vapors in percent - - answer -;Lower explosive limit
When manually lifting any object, be sure to _____. - - answer -;Keep it close to your body and use leg
strength
Hydrogen sulfide has a specific gravity of ___? - - answer -;1.2
Under what conditions may an operator refuse to work with a hazardous substance? - - answer -;When
the operator's employer has failed to provide or attempt to provide an MSDS sheet
QUESTIONS WITH COMPLETE SOLUTION GUIDE (A+
GRADED 100% VERIFIED) LATEST VERSION 2025!!
Batch processes are used to treat metal wastes because they are: - - answer -;Simple, dependable,
regulated until the wastewater being treated receives satisfactory treatment, and they are easy to
control
Sulfide precipitation can achieve lower metals concentrations in the final effluent than hydroxide
precipitation. T/F? - - answer -;TRUE
For tertiary denitrification, this supplemental carbon source is often added. - - answer -;Methanol
Nitrogen and phosphorus must be removed from the effluent before farmers can irrigate with the
treated effluent. T/F? - - answer -;FALSE
What is the correct order of nitrification? - - answer -;Ammonium à Nitrite à Nitrate
The optimum pH for nitrification is between. - - answer -;9-Aug
Without mineral additions for phosphorus removal, the expected percent phosphorus removal in an
activated sludge system is - - answer -;10 - 30%
Nitrosomonas & Nitrobacter are ______ ______, needing oxygen to survive. - - answer -;Obligate
aerobes
,This is the primary reason for limiting nitrate concentrations in receiving waters. - - answer -;Drinking
water standard of 10 mg/L NO3-N
With respect to natural systems, this element is most often the one that limits the growth of algae and
other organisms. - - answer -;Phosphorus
Name the two nitrifying bacteria. - - answer -;Nitrosomonas and Nitrobacter
It is advantageous to denitrify following nitrification as nearly half of this may be recovered. - - answer -
;Alkalinity
Which is not a chemical used to precipitate phosphorus from a wastewater effluent? - - answer -;Sulfur
dioxide
In addition to oxygen, nitrifiers consume bicarbonate alkalinity and produce carbonic acid. T/F? - -
answer -;TRUE
Biological phosphorus conditioning occurs in what zone? - - answer -;Fermentation
Biological phosphorus removal requires the presence of this type of chamber just ahead of the aeration
basins. - - answer -;Anaerobic
Theoretically, ____lbs. of alkalinity is consumed per lb. of ammonia - - answer -;7.14
What happens when denitrification takes place in the clarifier blanket? - - answer -;Floating sludge /
Blanket Pops / Rising Sludge
The biomass of a conventional activated sludge process contains about 2% phosphorus on a dry weight
basis? T/F? - - answer -;TRUE
,This concentration of nitrite is typical for a wastewater treatment plant effluent. - - answer -;< 0.5 mg/L
NO2-N
The two technologies for biological phosphorus removal are _____ stream and _______ stream. - -
answer -;Main and side
Assuming good mixing conditions, where is the optimal chemical feed point for phosphorus removal
with minimal chemical sludge production? - - answer -;At or near the end of the biological treatment
All of these requirements must be met before denitrification can take place. - - answer -;Presence of
food (BOD), absence of oxygen, and presence of nitrate
Since nitrification is an acid generating process, it consumes __________. - - answer -;Alkalinity
While BOD removal requires 1.5 lbs of oxygen per lb of BOD, nitrification requires this many lbs per lb of
ammonia nitrogen. - - answer -;4.33
This common atmospheric gas is the end product of denitrification. - - answer -;Nitrogen gas
Oxygen deficiency becomes a concern when the oxygen level in a confined space is less than - - answer -
;19.50%
Forklift accidents are particularly dangerous because of - - answer -;The tremendous weight of the
forklift
Which of the following hazardous chemicals is a hydrocarbon? Phosphoric acid, sodium hydroxide,
methane, ferric chloride. - - answer -;Methane
When working in confined spaces where flammable gases may be present, use only tools made of ____.
- - answer -;A non-sparking alloy
When chlorine reacts with H2S gas, the H2S is - - answer -;Oxidized and made odorless
, If your 1 ton chlorine cylinder is leaking, what type of Chlorine Institute repair kit should be used? - -
answer -;B
Pulmonary capacity tests are required before operators can be cleared for using respiratory equipment.
These tests should be performed at a a minimum of once every...? - - answer -;3 years
What types of wastes generally are prohibited from discharge to wastewater treatment plants? - -
answer -;Corrosives with a pH lower than 5.0
According to Article 250 of the US National Electric Code (NEC), what color should ground wires be? - -
answer -;Green
In a confined space entry, the entry supervisor must ensure that all confined space entry permit
provisions have been fulfilled and certify the same by signing the permit. T/F? - - answer -;TRUE
"Flammable" liquids have a flash point _________ 100 degrees F. - - answer -;Below
If you need to raise your voice to be heard by someone less than 2 ft away, chances are you should be
wearing hearing protection. T/F? - - answer -;TRUE
When used to ventilate a manhole, a portable blower should be at least _____ ft away. - - answer -;7
Combustible gas detectors measure gases and vapors in percent - - answer -;Lower explosive limit
When manually lifting any object, be sure to _____. - - answer -;Keep it close to your body and use leg
strength
Hydrogen sulfide has a specific gravity of ___? - - answer -;1.2
Under what conditions may an operator refuse to work with a hazardous substance? - - answer -;When
the operator's employer has failed to provide or attempt to provide an MSDS sheet
