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C14: The Earth's Resources - Coggle Diagram
C14: The Earth's Resources
14.1 Finite & Renewable Resources
Finite Resources - Being used up at a faster rate than than they can be replaced
Renewable Resources - Being replaced at the same rate its being consumed
Examples of finite resources: metal ores, crude oil, limestone, fossil fuels
Examples of renewable resources: biofuel
14.3 Treating Waste Water
Sewage water requires treatment before being released into the environment
Sewage treatment requires removal of organic matter, harmful microorganisms, and chemicals
1) Screening - remove large solid objects and grit by passing the waste water through a metal grid
2) Primary Treatment (Sedimentation) - Smaller solids allowed to settle in a large circular tank, large paddles rotate pushing the solids (sludge) towards the centre of the tank and removed, watery part (effluent) goes to the next tank
3) Secondary Treatment (Biological) - In the next tank useful bacteria is used to feed on any organic matter and harmful microorganisms still there, breaking them down aerobically (tank is aerated so oxygen is always present)
4) Final Treatment (Secondary Sedimentation) - Bacteria settle at the bottom and removed to be reused
Sludge is broken down anaerobically and can be dried and used as fertiliser or as a renewable energy source
14.4 Extracting Metals from Ores
Most copper is extracted by smelting copper-rich ores
Copper can be extracted from copper compounds through electrolysis (also used to purify impure copper)
Phytomining - Use plants to absorb compounds through its roots, then concentrates it in shoots and leaves, then burn plant and extract compound from the ashes
Bioleaching - Use of bacteria to absorb compounds and produce a high concentration solution (leachate) and can then be extracted from the solution by displacing it
14.6 Reduce, Reuse, Recycle
Social, economic, and environmental issues are associated with exploiting the Earth's limited supplies of raw materials
Recycling metals save energy and finite metal ores
Pollution caused by mining and extracting metals is also reduced by recycling
14.2 Water Safe to Drink
Potable - Water that is safe to drink (Must not have high levels of dissolved salts or microbes)
Water is made fit to drink by passing it through filter beds to remove solids and adding chlorine, ozone, or by passing ultraviolet light through it to reduce microbes
Reverse osmosis uses membranes to separate dissolved salts from salty water, but uses lots of energy to make high pressures needed (deslaination)
14.5 Life Cycle Assessments
Carried out to assess the environmental impact of products, processes or services
Raw material extraction > raw material processing > manufacturing & packaging > transport > use of product > disposal after use
Assigning numerical values to the relative effects of pollutants involves subjective judgment, must be very clear