Further treatment of water

Further treatment of water: chlorination

Chlorination

• Chlorine is added into water• Small portion is enough to kill micro-organisms

• Distillation needs high cost $$$$

Chlorine can kill micro-organisms in water.

Chlorine is a chemical.

It has a strange smell.

It is used in swimming pool.

Further treatment of water: fluoridation

Food remains in mouth

Bacteria grows and produce acids

Acids attack teeth

Tooth decayTooth decayTooth decayTooth decay

Further treatment of water: fluoridation

•Fluoride protects teeth

Fluoridation

•Fluoride is added to drinking water

•We drink fluoride in water

•Prevent teeth decay

Fluoride is added into water to protect our teeth but some people do not agree.

Do you?

Further treatment of water: fluoridation