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C14 The Earth's resources, image, image, image, image - Coggle Diagram
C14 The Earth's resources
14.1 Finite and renewable resources
Finite
resources is something that
will run out eventually
as it is being used up at a faster rate than it can be
replaced
. E.g. Nuclear fuels, coal, oil, gas.
Renewable
resources are ones which are not going
to run out
as they are being used at the
same rate
they are replaced. E.g. Wood, cotton, solar, wind.
Natural
products are products which occur
naturally
and are not
man made.
E.g. Wood, cotton.
Synthetic
products are
man made
. E.g. Nylon, PVC, polyester.
The chemical industry uses
natural resources
to make
new
products, for example:
metal ores
used to extract metal,
crude oil
used to make polymers,
limestone
to make cement and concrete, crude oil to make petrol and diesel.
14.2 Water safe to drink
Pure water is
100% H2O.
Nothing is added to it. It is
safe
to drink.
Potable
water is safe to drink but also
contains mineral ions e.g. dissolved impurities.
Steps to make fresh water potable.
Filtering
- water is passed through filter beds to remove solid particles.
Sterilisation
- water is sterilised by adding chlorine, ozone, or by passing ultraviolet light through the water.
Seawater or salty water can be made potable by
desalination
. However, it is an
expensive
process, because of the
large energy costs involved in heating the salty water.
Pure water can be made by
distillation
.
A process called
reverse osmosis
is also used to desalinate water. This uses
membranes
to s
eparate water from the salts dissolved in it.
14.3 Treating waste water
Sewage is the general name for
waste water from homes, businesses, and industry.
Sewage treatment
removes organic matter and harmful microorganisms from sewage and agricultural waste water.
Industrial waste water may also need harmful chemicals removing. This process makes sewage
safe
so it can be returned to the
environment
.
Steps
Screening
- this removes large solid objects and grit from the waste water.
Sedimentation
- solid sediments (sludge) settle out from the mixture. The watery liquid above the sludge is called effluent. Effluent still contains many potentially harmful microorganisms.
Aerobic biological treatment
- in the effluent useful bacteria feed on any remaining organic matter and harmful microorganisms. This breaks them down aerobically (in the presence of oxygen)
The sludge contains organic matter, including human waste, suspended solids, water and dissolved compounds. It is digested
anaerobically
(without oxygen) by microorganisms. The dried sludge can then be used as fertiliser or as a source of renewable energy.
