Page 1 of 41
TEXAS CLASS C WASTEWATER TREATMENT
LICENSE 2026 EXAM COMPLETE CURRENT
TESTING QUESTIONS AND DETAILED
CORRECT ANSWERS (VERIFIED)
GUARANTEED PASS/TOP-RATED A+.
WASTEWATER
Maximize your success on the Texas Class C Wastewater
Treatment License exam with focused preparation that
strengthens your understanding of preliminary and secondary
treatment processes, disinfection, solids handling, and Texas
Commission on Environmental Quality (TCEQ) regulations for
wastewater facilities. It is specifically designed for wastewater
operators in Texas seeking certification to manage a Class C
treatment facility.
Essential needs of an efficient wastewater stabilization
pond... ✓ ✓...... ANSWER ....... DO, algae and bacteria
The ideal orientation of a wastewater stabilization pond
would be... ✓ ✓...... ANSWER ....... parallel with
prevailing winds
, Page 2 of 41
What does short-circuiting in a pond cause? ✓ ✓......
ANSWER ....... reduction in detention time
A chemical factor influencing the efficiency of wastewater
stabilization ponds is... ✓ ✓...... ANSWER ....... carbon
dioxide
Good housekeeping around ponds includes... ✓ ✓......
ANSWER ....... keeping dike clean
Control tests on pond effluents include ✓ ✓...... ANSWER
....... BOD, TSS and pH
Purpose of return activated sludge ✓ ✓...... ANSWER .......
to reseed the biological reactor with treatment
microorganisms
Describe activated sludge... ✓ ✓...... ANSWER ....... is
fluffy and difficult to settle with approximately 99% moisture
content
, Page 3 of 41
How many times should a clarifier concentrate mixed liquor
solids? ✓ ✓...... ANSWER ....... at least two times
Purpose of wasting solids from an activated sludge system
is... ✓ ✓...... ANSWER ....... remove excess biological
solids, inert solids and old/dead microorganisms
Control parameters for activated sludge plants ✓ ✓......
ANSWER ....... oxygen levels, wasting rates, sludge
quality, return rates and aerator solids levels
The air requirements in an activated sludge process are
governed by... ✓ ✓...... ANSWER ....... organic loading on
the plant
Sludge bulking is corrected by.... ✓ ✓...... ANSWER .......
restoring environmental balance to favor floc-forming
bacteria over filamentous organisms
Rising sludge and gas bubbles can be caused by... ✓ ✓......
ANSWER ....... denitrification in the final clarifier
, Page 4 of 41
What test can give operators a visual check on sludge
quality? ✓ ✓...... ANSWER ....... 30-minute settling test
A conventional activated sludge process has primary
clarifiers that remove about ________ percent of the organic
load.. ✓ ✓...... ANSWER ....... 30-40%
What activated sludge process parameters can an operator
change directly? ✓ ✓...... ANSWER ....... aeration rates,
waste rates, and return sludge rates
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
TEXAS CLASS C WASTEWATER TREATMENT
LICENSE 2026 EXAM COMPLETE CURRENT
TESTING QUESTIONS AND DETAILED
CORRECT ANSWERS (VERIFIED)
GUARANTEED PASS/TOP-RATED A+.
WASTEWATER
Maximize your success on the Texas Class C Wastewater
Treatment License exam with focused preparation that
strengthens your understanding of preliminary and secondary
treatment processes, disinfection, solids handling, and Texas
Commission on Environmental Quality (TCEQ) regulations for
wastewater facilities. It is specifically designed for wastewater
operators in Texas seeking certification to manage a Class C
treatment facility.
Essential needs of an efficient wastewater stabilization
pond... ✓ ✓...... ANSWER ....... DO, algae and bacteria
The ideal orientation of a wastewater stabilization pond
would be... ✓ ✓...... ANSWER ....... parallel with
prevailing winds
, Page 2 of 41
What does short-circuiting in a pond cause? ✓ ✓......
ANSWER ....... reduction in detention time
A chemical factor influencing the efficiency of wastewater
stabilization ponds is... ✓ ✓...... ANSWER ....... carbon
dioxide
Good housekeeping around ponds includes... ✓ ✓......
ANSWER ....... keeping dike clean
Control tests on pond effluents include ✓ ✓...... ANSWER
....... BOD, TSS and pH
Purpose of return activated sludge ✓ ✓...... ANSWER .......
to reseed the biological reactor with treatment
microorganisms
Describe activated sludge... ✓ ✓...... ANSWER ....... is
fluffy and difficult to settle with approximately 99% moisture
content
, Page 3 of 41
How many times should a clarifier concentrate mixed liquor
solids? ✓ ✓...... ANSWER ....... at least two times
Purpose of wasting solids from an activated sludge system
is... ✓ ✓...... ANSWER ....... remove excess biological
solids, inert solids and old/dead microorganisms
Control parameters for activated sludge plants ✓ ✓......
ANSWER ....... oxygen levels, wasting rates, sludge
quality, return rates and aerator solids levels
The air requirements in an activated sludge process are
governed by... ✓ ✓...... ANSWER ....... organic loading on
the plant
Sludge bulking is corrected by.... ✓ ✓...... ANSWER .......
restoring environmental balance to favor floc-forming
bacteria over filamentous organisms
Rising sludge and gas bubbles can be caused by... ✓ ✓......
ANSWER ....... denitrification in the final clarifier
, Page 4 of 41
What test can give operators a visual check on sludge
quality? ✓ ✓...... ANSWER ....... 30-minute settling test
A conventional activated sludge process has primary
clarifiers that remove about ________ percent of the organic
load.. ✓ ✓...... ANSWER ....... 30-40%
What activated sludge process parameters can an operator
change directly? ✓ ✓...... ANSWER ....... aeration rates,
waste rates, and return sludge rates
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
