c10

• what do humans use the Earth's resources for

  warmth, shelter, food and transport
• what do natural resources supplemented by agriculture provide

  food, timber, clothing and fuels
• what is a finite resource


  one that will eventually run out
• whats a natural resource

  materials from the Earth that people use to live
• what is water that's safe to drink called

  potable water
• why is potable water not pure water

  it contains dissolved substances
• what do the methods used to produce potable water depend on

  available supplies of water and local conditions
• in the UK how is most potable water produced

  - by choosing an appropriate source of fresh water

  - passing the water through filter beds

  - sterilising
• examples of sterilising agents used for potable water

  chlorine, ozone, ultraviolet light
• if supplies of fresh water are limited what may be required

  desalination of salty water or sea water
• how is desalination done

  distillation or process which use membranes like reverse osmosis
• purification of waste water

  1) screening

  
  

  2) sedimentation

  
  

  3) anaerobic digestion of sludge

  
  

  4)aerobic biological treatment of effluent
• how is potable water produced

  - fresh water from source is collected

  
  

  - passed through a filter bed to remove any particles

  
  

  - chlorine is added to kill bacteria

  
  

  - fluorine is added to reduce tooth decay
• whats an ore


  natural occurring solid material from which a metal / valuable mineral can be extracted profitably
• whats screening


  process of catching large objects like leaves
• what's flocculation
• what does sewage treatment include

  1. Screening and grit removal

  2. Sedimentation to produce sewage sludge and effluent

  3. Anaerobic digestion of sewage sludge

  4. Aerobic biological treatment of effluent
• examples of what produces large amounts of waste water

  urban lifestyles, industrial processes
• what is phytomining


  plants absorb metal ions and are then burnt to produce an ash that contains metal compounds
• process to phytomining


  1) plants absorb copper by being grown in soil containing ores

  
  

  2) plants are burnt and copper is extracted from copper compounds in the ash
• whats bioleaching


  using bacteria to produce leachate solutions that contain metal compounds
• process of bioleaching


  1) bacteria feed on low-grade copper ores

  
  

  2) by various processes a solution of copper ions (leachate) is formed

  
  

  3) this undergoes electrolysis to obtain the copper
• what are low-grade ores


  ores that only contain less than 1% of the metal
• how are low-grade ores extracted

  phytomining, bioleaching
• what is sustainable development


  development that meets the needs of the present without compromising the ability of future generations to meet their own needs
• what is reverse osmosis

  - sea water is passed through a membrane that only allows through the water molecules

  
  

  - it needs high pressure to push the water through the membrane

  
  

  - the high energy requires a lot of energy to produce
• what might sewage and agricultural waste water require removal of

  organic matter and harmful microbes
• what might industrial waste water require removal of

  organic matter and harmful chemicals
• advantage to sewage treatment

  reusing water
• disadvantage of sewage treatment

  if its not done properly could cause disease which is a risk factor
• advantage of purifying salt water

  - easy access

  
  

  - relatively easy
• advantage of phytomining and bioleaching

  - need less energy than traditional methods

  
  

  - less impact on the environment

  
  

  - can work on small concentrations
• disadvantage to phytomining and bioleaching

  slow to carry out
• why are LCAs carried out

  to assess the environmental impact of products in certain staged
• what stages do LCAs assess

  - extracting and processing raw material

  
  

  - manufacturing and packaging

  
  

  - use and operation during its lifetime

  
  

  - disposal at the end of it useful life
• what are raw materials

  goods that could be turned into something else
• example of products that can be reused and how

  - glass bottles

  
  

  - can be crushed and melted to make other glass products
• how can metals be reused

  by melting and recasting or reforming into different products
• whats corrosion


  destruction of materials by chemical reactions with substances in the environment
• how can corrosion be prevented

  by applying a coating that acts as a barrier