WTO - Water Treatment Operator Coagulation and Flocculation Questions and Answers

Question 1

An operator observes that while the coagulant dose is correct, the floc forming in the flocculation basin is very small and not settling properly.
Which of the following adjustments is most likely needed?

Accepted Answer

Decrease the flocculation mixing speed.

Answer

Increase the rapid mix speed.

Answer

Increase the pH of the water.

Answer

Decrease the detention time in the flocculation basin.

Question 2

What is the primary function of a coagulant, such as aluminum sulfate (alum), in the water treatment process?

Accepted Answer

To neutralize the electrical charges of suspended particles.

Answer

To disinfect the water by killing pathogens.

Answer

To soften the water by removing calcium and magnesium.

Answer

To adjust the pH of the water to a neutral level.

Question 3

A water treatment plant is experiencing a sudden increase in raw water turbidity after a heavy rainfall. To maintain finished water quality, the operator should first consider performing what procedure?

Accepted Answer

Performing a jar test.

Answer

Backwashing the filters.

Answer

Increasing the chlorine dosage.

Answer

Checking the clearwell level.

Question 4

Which of the following is NOT a primary factor influencing the efficiency of the coagulation and flocculation process?

Accepted Answer

Chlorine concentration

Answer

Water temperature

Answer

pH and Alkalinity

Answer

Mixing intensity and duration

Question 5

During the water treatment process, what is the correct sequence for coagulation and flocculation?

Accepted Answer

Rapid mixing followed by slow mixing.

Answer

Slow mixing followed by rapid mixing.

Answer

Addition of flocculant aids followed by the primary coagulant.

Answer

Flocculation occurs first, then coagulation.

Question 6

A streaming current monitor (SCM) is an online instrument used to optimize the coagulation process. What does this device measure?

Accepted Answer

The net ionic and colloidal surface charge in the water.

Answer

The turbidity of the water after sedimentation.

Answer

The pH of the water in the rapid mix chamber.

Answer

The flow rate of the coagulant feed pump.

An operator observes that while the coagulant dose is correct, the floc forming in the flocculation basin is very small and not settling properly.Which of the following adjustments is most likely needed?

An operator observes that while the coagulant dose is correct, the floc forming in the flocculation basin is very small and not settling properly.
Which of the following adjustments is most likely needed?