Water Purification Quiz

Which of the following is NOT a method of large-scale water purification?

• Sedimentation

• Filtration

• Boiling

• Coagulation

In large-scale water purification, what comes after coagulation?

• Disinfection

• Filtration

• Flocculation

• Storage

Rapid sand filters differ from slow sand filters in:

• Filtration rate

• Sand particle size

• Cleaning method

• All of the above

The minimum free residual chlorine level recommended at consumer end is:

• 0.1 mg/L

• 0.2 mg/L

• 0.5 mg/L

• 1.0 mg/L

Breakpoint chlorination refers to:

• The point where chlorination system breaks down

• The dose at which all chlorine demand is satisfied

• Maximum chlorine that can be added to water

• The point where chlorine becomes ineffective

Which factor most significantly affects chlorination efficiency?

• Water temperature

• pH of water

• Water color

• Container material

Horrocks apparatus is used to:

• Filter water

• Test residual chlorine in water

• Add chlorine to water

• Remove hardness from water

The indicator used in Horrocks apparatus is:

• Methyl orange

• Phenolphthalein

• Orthotolidine

• Litmus

A yellow color in the Horrocks test indicates:

• Water is not safe

• Presence of free residual chlorine

• Presence of bacteria

• Adequate chlorination not achieved

The recommended dose of bleaching powder for well disinfection is:

• 2.5 g per 1000 liters

• 25 g per 1000 liters

• 7 g per 1000 liters

• 0.7 g per 1000 liters