What is the correct order of water treatment?

• filtration, storage, disinfection, filtration, sedimentation, and coagulation

• filtration, coagulation, sedimentation, filtration, disinfection, and storage

• filtration, sedimentation, coagulation, storage, disinfection, and filtration

• filtration, disinfection, coagulation, storage, filtration, and sedimentation

This process uses gravel, sand, or activated carbon to remove smaller insoluble particles from water.

• sedimentation

• chlorination

• carbonation

• filtration

What is the purpose of the fine sand filter in the purification of water?

• to allow particles to settle

• to sort particles into layers

• to trap large particles

• to trap small particles

What is the first step in the water treatment process?

• coagulation

• filtration

• oxidation (aeration)

• chlorination (disinfection)

Among the following chemicals, which are added to the water in a water treatment plant?

• slaked lime

• alum (aluminium sulfate)

• chlorine

The diagram shows the stages in a water treatment plant. 

Among the following, which chemicals are added in the tank 1?

• slaked lime

• alum (aluminium sulfate)

• chlorine

In aeration (oxidation) tank, a few types of bacteria are added and used to treat the wastewater. What is the role of the bacteria?

• to digest organic matter

• to add chlorine

• nothing, we don't want them in there

• add nutrients to the sludge

What do sedimentation tanks do at the wastewater treatment plant?

• kill the pathogenic bacteria

• aerate (oxidise) the water for good bacteria to grow

• allow heavy materials to sink to the bottom

• filter the large pieces of debris

What word means the solid particles that have settled out during the sedimentation process?

• sediment

• settlement

• solute

• solid

Which substance is used in a sewage treatment system to kill harmful bacteria?

• ammonia

• chlorine

• alum

• slaked lime