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Water
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Drinking Water.
Water is made safe to drink by removing solids and killing bacteria.
Solids are removed by
filtration and sedimentation.
Water is allowed to flow through
stone and sand filter
beds
to remove solid materials.
The sand becomes finer
near to the bottom of the filter to remove small solids.
Tiny
particles that are still suspended in the water are allowed
to
settle out and fall to the bottom. This is called sedimentation.
Chlorine (or ozone) is bubbled through the water to kill
bacteria.
Ultraviolet light can also
be used to disinfect water.
Fluoride is sometimes added
for dental health. The safe clear
water is then pumped through underground
pipes to houses.
The quality of drinking
water is monitored by
environmental agencies for dissolved ions such
as nitrate.
Some people use water filters in their homes to make
their tap water
nicer to drink.
Water filters may contain
silver which has an anti-bacterial
effect
and carbon
which is good at removing tiny
particles.
Pure
water can only be produced by
distillation.
This requires a lot of energy and is expensive.
It is not
good to drink
distilled water because it removes
ions from the body which may lead to health problems.
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Water
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