Resources and Water

• how are the earths resources used

  warmth

  shelter

  food

  transport
• what is sustainability

  meeting the needs of current generations without compromising the future generations
• What is potable water

  water that is safe to drink with sufficiently low levels of dissolved ions and microbes
• how is potable water produced in the uk

  rain water collected in lakes and reservoirs

  passing the water through filter beds

  sterilisation to remove microbes using chlorine, ozone or UV light
• methods of desalination

  distillation

  reverse osmosis
• describe the method of distillation of sea water

  heat until boils

  collect and condense the steam to produce pure water
• pros and cons of distillation

  produces pure water

  high energy

  waste can be difficult to dispose of
• describe reverse osmosis

  water is under high pressure and passed through a membrane

  the pores allow through water molecules but trap most ions and other molecules
• Pros and cons of reverse osmosis

  water doesn’t need to be sterilised after

  high volume of waste water

  low efficiency

  continuous process
• how is sewage treated to make water

  screening and grit removal to remove large particles

  sedimentation to produce effluent

  aerobic digestion of effluent
• How is sewage treated to make biofuel

  Screening and grit removal

  sedimentation to produce sludge

  anaerobic digestion of sludge to produce biofuel
• what is phytomining

  plants absorb ions through their roots

  plants are burnt

  ash contains a high concentration of metal ions
• pros and cons of phytomining 


  used on low grade ore

  reduces the need for mining

  slow
• what is bioleaching

  bacteria absorb metal ions from low grade ores producing leachate solutions
• pros and cons of bioleaching

  Low environmental impact

  produces toxic substances like sulfuric acid
• how are metal extracted from leachate solutions

  displacement reactions

  electrolysis