Colorado WW Operator D EXAM 2025/2026 ACTUAL
COMPLETE REAL EXAM QUESTIONS WITH COMPLETE
VERIFIED SOLUTION GUIDE (A+ GRADED 100% CORRECT )
2025 NEWEST VERSION!!
Which of the following is not a basic backflow prevention
device? (A)
Corporation stop (B) Reduced pressure principle device (C)
Double check-valve assembly (D) None of these answers are
correct - ANSWER-Corporation stop
What is an in-stream process of cutting and screening
solids contained in
wastewater flow? - ANSWER-
Communition
The reverse-acting actuator on a control valve is pneumatic.
The valve is 50% open. As you decrease the input signal to the
valve, it opens 60%. The valve is functioning normally. T/F? -
ANSWER-TRUE
,In what order will bacteria break down the following oxygen-
containing compounds: sulfate, carbon dioxide, and nitrate.
That is, what is the source of bound oxygen that requires the
least amount of energy? - ANSWER-1. Carbon dioxide, 2.
Nitrate, 3. Sulfate
Flow that enters the wastewater collection system through
cracks and loose
joints in the sewer line is called what? -
ANSWER-Infiltration
What is the weir overflow rate of a 50-ft diameter clarifier if the
daily plant flow is
1 mgd? - ANSWER-6369 gal/d per feet
of weir
If the influent flow to the aeration basin is 5 MGD with a BOD
concentration of
200 mg/L, how much sludge will need to be wasted if the yield
is 0.7 lb/lb? -
ANSWER-5840
lbs
A plant has a 90-ft diameter sludge tank with a sidewall depth of
20 ft. The tank
,also has a conical bottom that is 8 ft deep. The tank has a sludge
liquid level of
15 ft(sidewater depth). How many gallons of sludge liquid
are in the tank? -
ANSWER-
840,255
What is the pumping rate in gpm of the following piston pump?
Diameter = 10
in, stroke length, 6in, strokes/min = 30 -
ANSWER-61.2 gpm
Calculate the lbs of BOD entering the trickling filter. Raw WW
flow = 1.5 MGD,
raw WW BOD = 150 mg/L, 30% reduction in BOD through
primary treatment. -
ANSWER-1310
lb/day
Find how many gallons of liquid are in a tank which measures
40' long, 25' wide
and 12' high. - ANSWER-
89772
, How many lbs/day chlorine will be used if the flow is
7,000,000 gpd and a
uniform dose of 1.2 mg/l is applied? -
ANSWER-70 lb
Compute the lagoon's detention time. Surface area = 6.0 acres,
average depth
= 3.0 ft, average daily flow = 0.25 MGD. -
ANSWER-24 days
One hundred mgd of secondary influent to a treatment plant
contains 110 mg/l of suspended solids. A side-stream from a 1-
mgd dewatering plant with 1200 mg/l suspended solids is
returned. What is the total suspended solids load on the
secondary treatment plant, in pounds? - ANSWER-101,750 lb
A plastic float is dropped into a wastewater channel and is
found to travel 10 feet in 4.2 seconds. The channel is 2.4 feet
wide and is flowing 1.8 feet deep. Calculate the flow rate of this
wastewater in cubic feet per second. - ANSWER-
10.3 ft3/sec
Calculate the F:M ratio. Influent flow volume = 1 MG, average
BOD to aeration tank = 140 mg/L, aeration tank capacity =
250,000 gal, MLSS concentration =
COMPLETE REAL EXAM QUESTIONS WITH COMPLETE
VERIFIED SOLUTION GUIDE (A+ GRADED 100% CORRECT )
2025 NEWEST VERSION!!
Which of the following is not a basic backflow prevention
device? (A)
Corporation stop (B) Reduced pressure principle device (C)
Double check-valve assembly (D) None of these answers are
correct - ANSWER-Corporation stop
What is an in-stream process of cutting and screening
solids contained in
wastewater flow? - ANSWER-
Communition
The reverse-acting actuator on a control valve is pneumatic.
The valve is 50% open. As you decrease the input signal to the
valve, it opens 60%. The valve is functioning normally. T/F? -
ANSWER-TRUE
,In what order will bacteria break down the following oxygen-
containing compounds: sulfate, carbon dioxide, and nitrate.
That is, what is the source of bound oxygen that requires the
least amount of energy? - ANSWER-1. Carbon dioxide, 2.
Nitrate, 3. Sulfate
Flow that enters the wastewater collection system through
cracks and loose
joints in the sewer line is called what? -
ANSWER-Infiltration
What is the weir overflow rate of a 50-ft diameter clarifier if the
daily plant flow is
1 mgd? - ANSWER-6369 gal/d per feet
of weir
If the influent flow to the aeration basin is 5 MGD with a BOD
concentration of
200 mg/L, how much sludge will need to be wasted if the yield
is 0.7 lb/lb? -
ANSWER-5840
lbs
A plant has a 90-ft diameter sludge tank with a sidewall depth of
20 ft. The tank
,also has a conical bottom that is 8 ft deep. The tank has a sludge
liquid level of
15 ft(sidewater depth). How many gallons of sludge liquid
are in the tank? -
ANSWER-
840,255
What is the pumping rate in gpm of the following piston pump?
Diameter = 10
in, stroke length, 6in, strokes/min = 30 -
ANSWER-61.2 gpm
Calculate the lbs of BOD entering the trickling filter. Raw WW
flow = 1.5 MGD,
raw WW BOD = 150 mg/L, 30% reduction in BOD through
primary treatment. -
ANSWER-1310
lb/day
Find how many gallons of liquid are in a tank which measures
40' long, 25' wide
and 12' high. - ANSWER-
89772
, How many lbs/day chlorine will be used if the flow is
7,000,000 gpd and a
uniform dose of 1.2 mg/l is applied? -
ANSWER-70 lb
Compute the lagoon's detention time. Surface area = 6.0 acres,
average depth
= 3.0 ft, average daily flow = 0.25 MGD. -
ANSWER-24 days
One hundred mgd of secondary influent to a treatment plant
contains 110 mg/l of suspended solids. A side-stream from a 1-
mgd dewatering plant with 1200 mg/l suspended solids is
returned. What is the total suspended solids load on the
secondary treatment plant, in pounds? - ANSWER-101,750 lb
A plastic float is dropped into a wastewater channel and is
found to travel 10 feet in 4.2 seconds. The channel is 2.4 feet
wide and is flowing 1.8 feet deep. Calculate the flow rate of this
wastewater in cubic feet per second. - ANSWER-
10.3 ft3/sec
Calculate the F:M ratio. Influent flow volume = 1 MG, average
BOD to aeration tank = 140 mg/L, aeration tank capacity =
250,000 gal, MLSS concentration =
