TEXAS CLASS C WASTEWATER TREATMENT
LICENSE TEST 2026/2027 EXAM QUESTIONS
ACCURATE ACTUAL EXAM / FREQUENTLY
TESTED QUESTIONS WITH DETAILED
ANSWERS | GUARANTEED PASS | GRADED A |
LATEST UPDATE
What happens when the return sludge rate is too low? -
....ANSWER...there will be insufficient organisms to treat
the waste load entering the aeration basin and the sludge
blanket in the secondary clarifier could become too high
Physical causes of sludge bulking are... -
....ANSWER...excessive hydraulic loading, settled sludge
that is not promptly removed from the clarifier, inadequate
weir lengths and improper ratio of depth to surface area of
the final clarifier
How deep should the clarifier blanket be? -
....ANSWER...filling the bottom 1/4
,Weir loadings should not exceed _________ gal/day/linear
foot of weir at peak flow (1 MGD or less plant). -
....ANSWER...20,000
Weir loadings should not exceed ___________
gal/day/linear foot of weir at peak flow (1 MGD or above
plant). - ....ANSWER...30,000
Is activated sludge aerobic or anaerobic? -
....ANSWER...aerobic
Why do pumps continually send RAS to the aeration
tank? - ....ANSWER...to reseed the biological reaction in
the aeration tank and remove accumulating sludge from the
clarifier
How much raw influent should return pumps be able to
provide? - ....ANSWER...50-150%
For an activated sludge process to work properly, an
operator much insure that... - ....ANSWER...enough
return activated sludge is sent tot he aerator to maintain the
process; solids do not accumulate in the clarifier; excess
,solids that develop in the process are removed frequently
enough to avoid build-up
During normal operations, the __________ will
concentrate sludge, making it 2-4 times denser than that of
the mixed liquor. - ....ANSWER...clarifier
Define F/M ratio - ....ANSWER...food to microorganism
ratio
How is F/M ratio calculated? - ....ANSWER...by dividing
the pounds of incoming BOD (food) by the pounds of
MLVSS (microorganisms) in the aeration tank
What conditions should an operator observe in a well
controlled activated sludge process? -
....ANSWER...surface turbulence/uniform roll pattern;
foam/small amount of light-colored, crisp foam; odors/mild,
earthy; color/medium-brown
What conditions should an operator observe in a well
controlled clarifier? - ....ANSWER...very little surface
scum; a sludge blanket covering 1/4 of the bottom; uniform
, weir flow (all the way around); almost no rising solids and
overflow should be clear and free of floc
What type solids cannot go onto a trickling filter? -
....ANSWER...large suspended solids
Important factors to a well operating trickling filter... -
....ANSWER...continuous food supply, aerobic conditions
and a moist zoogleal mass
Basic elements of a trickling filter are... -
....ANSWER...floor and walls; distributor arms;
underdrains and media
What must be durable and provide enough surface for
bacterial growth with a trickling filter? -
....ANSWER...filter media
The zoogleal mass on a filter is composed mainly of what?
- ....ANSWER...bacteria and algae
LICENSE TEST 2026/2027 EXAM QUESTIONS
ACCURATE ACTUAL EXAM / FREQUENTLY
TESTED QUESTIONS WITH DETAILED
ANSWERS | GUARANTEED PASS | GRADED A |
LATEST UPDATE
What happens when the return sludge rate is too low? -
....ANSWER...there will be insufficient organisms to treat
the waste load entering the aeration basin and the sludge
blanket in the secondary clarifier could become too high
Physical causes of sludge bulking are... -
....ANSWER...excessive hydraulic loading, settled sludge
that is not promptly removed from the clarifier, inadequate
weir lengths and improper ratio of depth to surface area of
the final clarifier
How deep should the clarifier blanket be? -
....ANSWER...filling the bottom 1/4
,Weir loadings should not exceed _________ gal/day/linear
foot of weir at peak flow (1 MGD or less plant). -
....ANSWER...20,000
Weir loadings should not exceed ___________
gal/day/linear foot of weir at peak flow (1 MGD or above
plant). - ....ANSWER...30,000
Is activated sludge aerobic or anaerobic? -
....ANSWER...aerobic
Why do pumps continually send RAS to the aeration
tank? - ....ANSWER...to reseed the biological reaction in
the aeration tank and remove accumulating sludge from the
clarifier
How much raw influent should return pumps be able to
provide? - ....ANSWER...50-150%
For an activated sludge process to work properly, an
operator much insure that... - ....ANSWER...enough
return activated sludge is sent tot he aerator to maintain the
process; solids do not accumulate in the clarifier; excess
,solids that develop in the process are removed frequently
enough to avoid build-up
During normal operations, the __________ will
concentrate sludge, making it 2-4 times denser than that of
the mixed liquor. - ....ANSWER...clarifier
Define F/M ratio - ....ANSWER...food to microorganism
ratio
How is F/M ratio calculated? - ....ANSWER...by dividing
the pounds of incoming BOD (food) by the pounds of
MLVSS (microorganisms) in the aeration tank
What conditions should an operator observe in a well
controlled activated sludge process? -
....ANSWER...surface turbulence/uniform roll pattern;
foam/small amount of light-colored, crisp foam; odors/mild,
earthy; color/medium-brown
What conditions should an operator observe in a well
controlled clarifier? - ....ANSWER...very little surface
scum; a sludge blanket covering 1/4 of the bottom; uniform
, weir flow (all the way around); almost no rising solids and
overflow should be clear and free of floc
What type solids cannot go onto a trickling filter? -
....ANSWER...large suspended solids
Important factors to a well operating trickling filter... -
....ANSWER...continuous food supply, aerobic conditions
and a moist zoogleal mass
Basic elements of a trickling filter are... -
....ANSWER...floor and walls; distributor arms;
underdrains and media
What must be durable and provide enough surface for
bacterial growth with a trickling filter? -
....ANSWER...filter media
The zoogleal mass on a filter is composed mainly of what?
- ....ANSWER...bacteria and algae
