Wastewater Exam Class C Questions with

Wastewater Exam Class C Questions with Correct Answers 100% Verified Rated A+

2023/2024

The Activated Sludge Process:

• requires preaeration
• requires Activated Carbon
• is an aerobic biological process.
• Usually precedes primary sedimentation.
• Requires 50% by volume old sludge to work effectively. - Correct Answer 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 :

• Increase the RAS Flow
• Reduce Wasting Rates
• Increase dissolved oxygen levels.
• Increase the F/M ratio by wasting more
• Increase the sludge age by wasting less. - Correct Answer 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?

• Aeration rate or resulting dissolved oxygen level.
• Influent or effluent.
• return sludge
• waste sludge
• all the above - Correct Answer E. all the above

During start up your aeration tank produces excessive amounts of billowing white foam.

This can be corrected by:

• Doing nothing, it will go away in a few hours
• Increasing the sludge wasting rate
• Seeding the process with sufficient good quality sludge
• Spraying water on the foam until it is gone
• Taking a weeks vacation - Correct Answer C. Seeding the process with sufficient

good quality sludge In solving an operational problem at a treatment plant: 1 / 2

• there is almost always a good technical solution. It may require considerable

experience and time to learn whaat it is.

• Human errors have to be corrected since the operator is at fault.
• don't let the laboratory personnel influence you're judgement as to what the best

solution is.

• standard textbooks in sanitary engineering are the best source of information.
• It is best to do nothing until the TNRCCC sends a violation notice. - Correct Answer
• 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?

• the aeration tank will not fill
• There will be insufficient organisms to treat the wast load entering the aeration basin
• the activated sludge in the aerator will starve.
• the sludge blanket in the secondary clarifier could become too high.
• B and D - Correct Answer E. B and D

What factors affect how well the mixed liquor suspended solids settle in the final clarifier?

• flow velocity and or turbulence
• temperature
• quality of the mixed liquor solids
• Short circuiting
• All of the above - Correct Answer E. All of the above

The Active sludge process parameters which n operator can change directly are:

• aeration rates.
• waste rates.
• the ratio of free swimming to stalked ciliates.
• Return sludge rates.
• All the above except C. - Correct Answer E. All the above except C.

Which of the following would you use to increase the degree of nitrification in an activated sludge plant?

• increase the wast rates
• increase dissolved oxygen levels and increase the sludge age
• Remove excess alkalinity from the wastewater
• Maintain a thicker sludge blanket n the clarifier
• Inhibit the growth of the nitrifying bacteria with chemicals. - Correct Answer B.

increase dissolved oxygen levels and increase the sludge age

• / 2