C10 - Using Resources

• Using the Earth’s resources and sustainable development

  • We use them to provide warmth, shelter, food and transport
• Natural Resources

  • Supplemented by agriculture, provide food, timber, clothes and fuels
• Finite Resources

  • Finite resources are those that are being used up at a faster rate than they can be replaced, and will eventually run out
• Finite Resources are processed to get us...

  • Energy
  • Materials
• Renewable

  • Renewable resources are those that can be replaced at the same rate at which they are used up
• Potable Water

  • Water that is safe to drink
  • However, potable water is not 'pure', because it contains dissolved substances, although to be safe it must have low levels of salts and microbes
• The methods used to obtain potable water:

  1. An appropriate source of fresh water is selected
  2. The water is passed through filter beds to remove different sized insoluble solids
  3. The water is then sterilised, to kill microbes (sterilising agents include: ozone, chlorine, UV light)
• The methods used to obtain potable water IF ONLY salty water is available:

  • Can be done by distillation
  • Done by processes with membranes e.g. reverse osmosis

  -> These processes require large amounts of energy and BOTH processes are very EXPENSIVE
• Sewage and Agricultural Waste

  • Sewage and agricultural waste water require removal of organic matter and harmful microbes
• Sewage Treatment

  1. Water is passed through a mesh screen to remove large bits
  2. Chemicals are added to make solids and microbes stick together to form sediment. This sediment sinks to the bottom forming sludge and the remaining liquid is called effluent
  3. The sewage sludge is anaerobically digested by bacteria
  4. The effluent is treated with aerobic bacteria which breaks it down
• Why is obtaining Potable water from Sewage waste / Salt water / Ground water good?

  • It's cheaper and easier to obtain
• What is happening to the amount of metal ores on Earth?

  • The Earth's resource of metal ores is limited
  • E.g. Copper Ores
• 2 methods to extract copper from low-grade ores:

  • Phytomining
  • Bioleaching
  • These methods avoid traditional mining methods of digging, moving and disposing large amounts of rocks
• Phytomining

  -> Uses plants to absorb metal compounds

  • Plants are grown
  • These plants are burned (which produce ash)
  • The ash is dissolved in acid to produce a solution of copper compound
  • THEN either electrolysis of solution OR displacement of copper from the solution to obtain copper
• Bioleaching

  • Uses bacteria to produce leachate solutions that contain metal compounds
• How can we obtain copper from the compound?

  • Electrolysis
  • Displacement using scrap iron
• Life Cycle Assessment

  • These are carried out to assess the environmental impact of products in each of these stages:
  • Extracting and processing raw materials
  • Manufacturing and packaging
  • Use and operation during its lifetime
  • Disposal at the end of its useful life, including transport and distribution at each stage.
• Reuse of Glass Bottles

  • Glass bottles can be crushed and melted to make different glass products.
• Recycling of Scrap Steel

  • Some scrap steel can be added to iron from a blast furnace to reduce the amount of iron that needs to be extracted from iron ore.
• Recycling Metals

  • Metals can be recycled by melting and recasting or reforming into different products.
  • The amount of separation required for recycling depends on the material and the properties required of the final product
• Water obtained by distillation does NOT need to be sterilised and is safe to drink. Suggest why.

  • Distilled water is pure
• Phytomining has NOT been widely used to extract copper. Suggest two reasons why.

  • Less land is available
  • Phytomining takes a long time
• Desalination is only used when there is no other source of potable water. Give one reason why

  • It's expensive
• Explain why it's more difficult to produce drinking water from waste water than from water in lakes.

  • Waste water needs more processes
  • Waste water contains more organic matter, microbes, toxic chemicals (Each of this elements are 1 mark)
• Advantages + Disadvantages of Bioleaching

  • ADVANTAGES -> Doesn't require high temperatures
  • DISADVANTAGES -> Produces toxic substances which harms the environment
• Advantages + Disadvantages of Phytomining

  • ADVANTAGES -> Reduces the need for mining / Conserves high-grade ores
  • DISADVANTAGES -> Slow process as it takes time for the plants to grow