10 1 global reserves and potable water

Humans use the Earth's resources for:

A finite resource is one which cannot be replaced so will run out.

Sustainable development is development that meets the needs of the current generations without compromising the ability of future generations to meet their own needs.

Examples of a natural product that can be replaced by synthetic or agricultural products include:

Renewable resources are ones which can be replenished or replaced.

True. Wood is an example of a renewable resource.

False. Rubber is an example of a natural resource as it is extracted from the sap of trees.

Potable water is water that is safe to drink.

False. Potable water is not pure as it contains dissolved substances such as salts and chlorine.

The two main steps used to produce potable water in the UK are

Chlorine is added to water to kill bacteria.

Three sterilising agents used to treat water are:

Water is filtered to remove insoluble solids.

Desalination is the removal of salt from water.

True. Distillation and reverse osmosis can remove salt from water.

Distillation is expensive because it requires large amounts of energy.

True. Potable water contains low levels of salts and microbes.

The main source of water in the UK is rain water collected in the ground, rivers and lakes.

Sources of waste water include:

The main steps involved in treating sewage are:

Sewage needs to be treated to remove organic matter and harmful microbes.

During the sedimentation of sewage, the water stands in a tank and the heavier solids sink to the bottom creating sewage sludge.

True. Aerobic digestion of the effluent requires oxygen.

False. The effluent is treated by aerobic digestion.

Once the effluent has undergone aerobic digestion the water is released back into the environment.

Sewage needs to be screened to remove large solid materials.

The by-products of anaerobic digestion of sewage sludge are used as fertiliser and methane as a source of energy.

Industrial waste water needs to be treated to remove organic matter and harmful chemicals.

False. There are limited amounts of metal ores.

A low-grade ore is one which contains a low concentration of the metal.

Two methods used to extract copper from low-grade ores are bioleaching and phytomining.

Bioleaching is used to extract copper from low-grade ores by using bacteria to produce a leachate solution that contains metal compounds.

Phytomining is used to extract metals from low grade ores by:

Disadvantages of using biological methods to extract metals from low-grade ores are:

False. Copper is obtained from a solution of its compound by displacement using scrap iron because it is cheap.

The methods used to extract copper from the copper compound obtained from phytomining or bioleaching are:

The symbol equation for the displacement reaction between copper sulfate and iron is: CuSO4 (aq) + Fe (s) → FeSO4 (aq) + Cu (s)

True. Phytomining and bioleaching are not just used to extract copper from low-grade ores, they can be used to extract other metals but they are mainly used to for copper due to its high global demand.

Advantages of using biological methods to extract metals from low-grade ores include:

It is necessary to extract copper from low-grade ores because high-grade copper ores are becoming scarce.