Using the Earth's resources and obtaining potable water

• We use the Earth's resources to provide warmth, shelter, food and transport.
• Natural resources, supplemented by agriculture, provide food, timber, clothing and fuels.
• Finite resources from the Earth, oceans and atmosphere are processed to provide energy and materials.
• Bioleaching uses bacteria to produce leachate solutions that contain metal compounds.
• The metal compounds can be processed to obtain the metal.
• Plants are harvested and then burned to produce ash that contains metal compounds.
• For example, copper can be obtained from solutions of copper compounds by displacement using scrap iron or by electrolysis.
• Chemistry plays an important role in improving agricultural and industrial processes to provide new products and in sustainable development, which is development that meets the needs of current generations without compromising the ability of future generations to meet their own needs.
• Renewable energy resources: sources of power that quickly replenish themselves and can be used again, only includes plants/wood if they continue to be re-planted.
• Finite resources: have a limited supply that will eventually run out.
• Potable water is water that is safe to drink and is not 'pure' because it contains dissolved substances, although to be safe it must have sufficiently low levels of dissolved salts and microbes.
• The methods used to produce potable water depend on available supplies of water and local conditions.
• There is anaerobic digestion of sewage sludge.
• In the UK, an appropriate source of fresh water is selected, such as rain which provides water with low levels of dissolved substances and this collects in the ground, rivers, or lakes.
• If only salty/sea water is available, desalination is required, which can be done by distillation or using processes with membranes like reverse osmosis.
• Earth’s resources of metal ores are limited.
• Water is passed through a mesh screen to remove large bits such as twigs or grit.
• Phytomining uses plants to absorb metal compounds.
• The water is passed through filter beds to remove different sized insoluble solids.
• Water of the correct quality is essential for life and must be free of poisonous salts and harmful microbes.
• The water is then sterilised with chlorine to kill any microbes left.
• It is relatively cheaper and easier to obtain potable water from groundwater and wastewater than salt water, although seawater is a plentiful raw material, so is good for countries with little fresh water.
• Chemicals are added to make solids and microbes stick together to form sediment and sink.
• Copper ores are becoming scarce and new ways of extracting copper from low-grade ores include phytomining, and bioleaching.
• Both distillation and reverse osmosis are very expensive processes.
• The water is then sterilised, to kill microbes, using sterilising agents like ozone, UV light, or chlorine.