earths resources

Finite resources

Natural resources that are used faster than they can be replenished

Examples of finite resources

metal ores, crude oil, limestone

Renewable resources

Natural resources that can be replaced.

Examples of renewable resources

Cotton, wheat, wood

Potable water

Water that is safe to drink but contains dissolved ions

Pure water

Only water molecules

Fresh water

Water that contains insignificant amounts of salts, as in rivers and lakes.

Source of UK potable water

Fresh water

Filter beds

Remove insoluble solids from fresh water in a water treatment plant

Sterilisation

Killing pathogens in water using UV light/Chlorine/Ozone

Desalination

Removal of salt from seawater to make it usable for drinking and farming

Reverse osmosis

A type of desalination in which water is forced through a thin semipermeable membrane at high pressure

Test for pure water

Measure the boiling point, pure water is 100°C

Measuring dissolved solids in water

Evaporate water and weigh the solids

Waste water

Sewage and agricultural waste

Screening and grit removal

The removal of large solid objects from waste water

Sedimentation of waste water

Separating waste water into sewage sludge and effluent

Sewage sludge

the solid material that remains after wastewater treatment

Effluent

liquid waste or sewage

Secondary treatment of wastewater

Aerobic digestion of effluent to remove organic matter and pathogens

Biogas

A fuel made of methane and carbon dioxide produced by anaerobic digestion of organic matter.

Sludge treatment

Anaerobic digestion of sewage sludge to produce biogas

Sustainable development

Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.