WASTEWATER CLASS C EXAM 2025
QUESTIONS AND ANSWERS
The Activated Sludge Process:
A. requires preaeration
B. requires Activated Carbon
C. is an aerobic biological process.
D. Usually precedes primary sedimentation.
E. Requires 50% by volume old sludge to work effectively. - ANS C. Is an Aerobic biological
process
A complete mix activated sludge plant has a fast settling sludge and high amounts of pin floc
leaving the clarifier. One way to correct this problem is to :
A. Increase the RAS Flow
B. Reduce Wasting Rates
C. Increase dissolved oxygen levels.
D. Increase the F/M ratio by wasting more
E. Increase the sludge age by wasting less. - ANS D. Increase the F/M Ratio by Wasting More
Which of the following flow rates should be measured if the operator is to control plant
properly?
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, A. Aeration rate or resulting dissolved oxygen level.
B. Influent or effluent.
C. return sludge
D. waste sludge
E. all the above - ANS E. all the above
During start up your aeration tank produces excessive amounts of billowing white foam. This
can be corrected by:
A. Doing nothing, it will go away in a few hours
B. Increasing the sludge wasting rate
C. Seeding the process with sufficient good quality sludge
D. Spraying water on the foam until it is gone
E. Taking a weeks vacation - ANS C. Seeding the process with sufficient good quality sludge
In solving an operational problem at a treatment plant:
A. there is almost always a good technical solution. It may require considerable experience and
time to learn whaat it is.
B. Human errors have to be corrected since the operator is at fault.
C. don't let the laboratory personnel influence you're judgement as to what the best solution is.
D. standard textbooks in sanitary engineering are the best source of information.
E. It is best to do nothing until the TNRCCC sends a violation notice. - ANS A. there is almost
always a good technical solution. It may require considerable experience and time to learn
whaat it is.
When the return sludge rate is too low, what happens?
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 2
QUESTIONS AND ANSWERS
The Activated Sludge Process:
A. requires preaeration
B. requires Activated Carbon
C. is an aerobic biological process.
D. Usually precedes primary sedimentation.
E. Requires 50% by volume old sludge to work effectively. - ANS C. Is an Aerobic biological
process
A complete mix activated sludge plant has a fast settling sludge and high amounts of pin floc
leaving the clarifier. One way to correct this problem is to :
A. Increase the RAS Flow
B. Reduce Wasting Rates
C. Increase dissolved oxygen levels.
D. Increase the F/M ratio by wasting more
E. Increase the sludge age by wasting less. - ANS D. Increase the F/M Ratio by Wasting More
Which of the following flow rates should be measured if the operator is to control plant
properly?
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 1
, A. Aeration rate or resulting dissolved oxygen level.
B. Influent or effluent.
C. return sludge
D. waste sludge
E. all the above - ANS E. all the above
During start up your aeration tank produces excessive amounts of billowing white foam. This
can be corrected by:
A. Doing nothing, it will go away in a few hours
B. Increasing the sludge wasting rate
C. Seeding the process with sufficient good quality sludge
D. Spraying water on the foam until it is gone
E. Taking a weeks vacation - ANS C. Seeding the process with sufficient good quality sludge
In solving an operational problem at a treatment plant:
A. there is almost always a good technical solution. It may require considerable experience and
time to learn whaat it is.
B. Human errors have to be corrected since the operator is at fault.
C. don't let the laboratory personnel influence you're judgement as to what the best solution is.
D. standard textbooks in sanitary engineering are the best source of information.
E. It is best to do nothing until the TNRCCC sends a violation notice. - ANS A. there is almost
always a good technical solution. It may require considerable experience and time to learn
whaat it is.
When the return sludge rate is too low, what happens?
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 2
