WTO Coagulation and Flocculation 2

Question 1

What is the primary purpose of a jar test in water treatment?

Accepted Answer

To determine the optimal coagulant dose and pH

Answer

The jar test simulates the coagulation-flocculation process at bench scale to find the best coagulant dose and pH before full-scale application.

Question 2

Zeta potential is used in water treatment to measure:

Accepted Answer

The surface charge of suspended particles

Answer

Zeta potential quantifies the electrokinetic charge on colloidal particles, indicating how well coagulation has neutralized particle charges.

Question 3

Which of the following best describes 'sweep flocculation'?

Accepted Answer

Entrapping particles in a precipitate of metal hydroxide

Answer

Sweep flocculation occurs when excess metal coagulant forms a hydroxide precipitate that sweeps particles out of suspension as it settles.

Question 4

Ferric sulfate as a coagulant is most advantageous over alum in water with:

Accepted Answer

High pH and low turbidity

Answer

Ferric sulfate performs better than alum at higher pH values because ferric hydroxide is less soluble over a wider pH range.

Question 5

What effect does low water temperature have on flocculation?

Accepted Answer

It slows floc formation because water viscosity increases

Answer

Cold water is more viscous, which reduces particle collision frequency and slows floc growth, often requiring longer detention times or higher coagulant doses.

(WTO) Water Treatment Operator Certification Practice Test

(WTO) Water Treatment Operator Certification Practice Test

WTO Coagulation and Flocculation 2